Optionally require a valid content type for all rest requests with content (#22691)

This change adds a strict mode for xcontent parsing on the rest layer. The strict mode will be off by default for 5.x and in a separate commit will be enabled by default for 6.0. The strict mode, which can be enabled by setting `http.content_type.required: true` in 5.x, will require that all incoming rest requests have a valid and supported content type header before the request is dispatched. In the non-strict mode, the Content-Type header will be inspected and if it is not present or not valid, we will continue with auto detection of content like we have done previously. The content type header is parsed to the matching XContentType value with the only exception being for plain text requests. This value is then passed on with the content bytes so that we can reduce the number of places where we need to auto-detect the content type. As part of this, many transport requests and builders were updated to provide methods that accepted the XContentType along with the bytes and the methods that would rely on auto-detection have been deprecated. In the non-strict mode, deprecation warnings are issued whenever a request with body doesn't provide the Content-Type header. See #19388
author: Jay Modi <jaymode@users.noreply.github.com> 2017-02-02 14:07:13 -0500
committer: GitHub <noreply@github.com> 2017-02-02 14:07:13 -0500
commit: 7520a107bee67099338813728147d2aee25ed240 (patch)
tree: 22828e74c5aa601c185c36c7463665fbfeaa4c51
parent: b41d5747f0bd67dad05c8168312ba456bcdaebda (diff)
252 files changed, 3696 insertions, 1022 deletions
diff --git a/client/benchmark/src/main/java/org/elasticsearch/client/benchmark/transport/TransportClientBenchmark.java b/client/benchmark/src/main/java/org/elasticsearch/client/benchmark/transport/TransportClientBenchmark.java
index 6d6e5ade82..c5a544eb78 100644
--- a/client/benchmark/src/main/java/org/elasticsearch/client/benchmark/transport/TransportClientBenchmark.java
+++ b/client/benchmark/src/main/java/org/elasticsearch/client/benchmark/transport/TransportClientBenchmark.java
@@ -28,6 +28,7 @@ import org.elasticsearch.client.benchmark.ops.search.SearchRequestExecutor;
 import org.elasticsearch.client.transport.TransportClient;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.TransportAddress;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.plugin.noop.NoopPlugin;
 import org.elasticsearch.plugin.noop.action.bulk.NoopBulkAction;
@@ -80,7 +81,7 @@ public final class TransportClientBenchmark extends AbstractBenchmark<TransportC
         public boolean bulkIndex(List<String> bulkData) {
             NoopBulkRequestBuilder builder = NoopBulkAction.INSTANCE.newRequestBuilder(client);
             for (String bulkItem : bulkData) {
-                builder.add(new IndexRequest(indexName, typeName).source(bulkItem.getBytes(StandardCharsets.UTF_8)));
+                builder.add(new IndexRequest(indexName, typeName).source(bulkItem.getBytes(StandardCharsets.UTF_8), XContentType.JSON));
             }
             BulkResponse bulkResponse;
             try {
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkRequestBuilder.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkRequestBuilder.java
index ceaf9f8cc9..1034e722e8 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkRequestBuilder.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkRequestBuilder.java
@@ -33,6 +33,7 @@ import org.elasticsearch.action.update.UpdateRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 
 public class NoopBulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkResponse, NoopBulkRequestBuilder>
         implements WriteRequestBuilder<NoopBulkRequestBuilder> {
@@ -95,17 +96,17 @@ public class NoopBulkRequestBuilder extends ActionRequestBuilder<BulkRequest, Bu
     /**
      * Adds a framed data in binary format
      */
-    public NoopBulkRequestBuilder add(byte[] data, int from, int length) throws Exception {
-        request.add(data, from, length, null, null);
+    public NoopBulkRequestBuilder add(byte[] data, int from, int length, XContentType xContentType) throws Exception {
+        request.add(data, from, length, null, null, xContentType);
         return this;
     }
 
     /**
      * Adds a framed data in binary format
      */
-    public NoopBulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType)
-        throws Exception {
-        request.add(data, from, length, defaultIndex, defaultType);
+    public NoopBulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType,
+                                      XContentType xContentType) throws Exception {
+        request.add(data, from, length, defaultIndex, defaultType, xContentType);
         return this;
     }
 
diff --git a/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/RestNoopBulkAction.java b/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/RestNoopBulkAction.java
index 7765b10534..5d4215b3de 100644
--- a/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/RestNoopBulkAction.java
+++ b/client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/RestNoopBulkAction.java
@@ -73,7 +73,8 @@ public class RestNoopBulkAction extends BaseRestHandler {
         }
         bulkRequest.timeout(request.paramAsTime("timeout", BulkShardRequest.DEFAULT_TIMEOUT));
         bulkRequest.setRefreshPolicy(request.param("refresh"));
-        bulkRequest.add(request.content(), defaultIndex, defaultType, defaultRouting, defaultFields, null, defaultPipeline, null, true);
+        bulkRequest.add(request.content(), defaultIndex, defaultType, defaultRouting, defaultFields, null, defaultPipeline, null, true,
+            request.getXContentType());
 
         // short circuit the call to the transport layer
         return channel -> {
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
index a06175a598..f0f8d50b4c 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequest.java
@@ -142,9 +142,11 @@ public class PutRepositoryRequest extends AcknowledgedRequest<PutRepositoryReque
     /**
      * Sets the repository settings.
      *
-     * @param source repository settings in json, yaml or properties format
+     * @param source repository settings in json or yaml format
      * @return this request
+     * @deprecated use {@link #settings(String, XContentType)} to avoid content type auto-detection
      */
+    @Deprecated
     public PutRepositoryRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
@@ -153,6 +155,18 @@ public class PutRepositoryRequest extends AcknowledgedRequest<PutRepositoryReque
     /**
      * Sets the repository settings.
      *
+     * @param source repository settings in json or yaml format
+     * @param xContentType the content type of the source
+     * @return this request
+     */
+    public PutRepositoryRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
+     * Sets the repository settings.
+     *
      * @param source repository settings
      * @return this request
      */
@@ -160,7 +174,7 @@ public class PutRepositoryRequest extends AcknowledgedRequest<PutRepositoryReque
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
index 39cfa6af7f..aed09daff2 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryRequestBuilder.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action.admin.cluster.repositories.put;
 import org.elasticsearch.action.support.master.AcknowledgedRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Map;
 
@@ -89,17 +90,31 @@ public class PutRepositoryRequestBuilder extends AcknowledgedRequestBuilder<PutR
     }
 
     /**
-     * Sets the repository settings in Json, Yaml or properties format
+     * Sets the repository settings in Json or Yaml format
      *
      * @param source repository settings
      * @return this builder
+     * @deprecated use {@link #setSettings(String, XContentType)} instead to avoid content type auto detection
      */
+    @Deprecated
     public PutRepositoryRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
+     * Sets the repository settings in Json or Yaml format
+     *
+     * @param source repository settings
+     * @param xContentType the contenty type of the source
+     * @return this builder
+     */
+    public PutRepositoryRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the repository settings
      *
      * @param source repository settings
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
index e5f5bdb7fb..bd0110e644 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequest.java
@@ -83,13 +83,23 @@ public class ClusterUpdateSettingsRequest extends AcknowledgedRequest<ClusterUpd
 
     /**
      * Sets the source containing the transient settings to be updated. They will not survive a full cluster restart
+     * @deprecated use {@link #transientSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public ClusterUpdateSettingsRequest transientSettings(String source) {
         this.transientSettings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * Sets the source containing the transient settings to be updated. They will not survive a full cluster restart
+     */
+    public ClusterUpdateSettingsRequest transientSettings(String source, XContentType xContentType) {
+        this.transientSettings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Sets the transient settings to be updated. They will not survive a full cluster restart
      */
     @SuppressWarnings("unchecked")
@@ -97,7 +107,7 @@ public class ClusterUpdateSettingsRequest extends AcknowledgedRequest<ClusterUpd
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            transientSettings(builder.string());
+            transientSettings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -122,13 +132,23 @@ public class ClusterUpdateSettingsRequest extends AcknowledgedRequest<ClusterUpd
 
     /**
      * Sets the source containing the persistent settings to be updated. They will get applied cross restarts
+     * @deprecated use {@link #persistentSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public ClusterUpdateSettingsRequest persistentSettings(String source) {
         this.persistentSettings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * Sets the source containing the persistent settings to be updated. They will get applied cross restarts
+     */
+    public ClusterUpdateSettingsRequest persistentSettings(String source, XContentType xContentType) {
+        this.persistentSettings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Sets the persistent settings to be updated. They will get applied cross restarts
      */
     @SuppressWarnings("unchecked")
@@ -136,7 +156,7 @@ public class ClusterUpdateSettingsRequest extends AcknowledgedRequest<ClusterUpd
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            persistentSettings(builder.string());
+            persistentSettings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
index f0492edfeb..906b1867b1 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsRequestBuilder.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action.admin.cluster.settings;
 import org.elasticsearch.action.support.master.AcknowledgedRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Map;
 
@@ -52,13 +53,23 @@ public class ClusterUpdateSettingsRequestBuilder extends AcknowledgedRequestBuil
 
     /**
      * Sets the source containing the transient settings to be updated. They will not survive a full cluster restart
+     * @deprecated use {@link #setTransientSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public ClusterUpdateSettingsRequestBuilder setTransientSettings(String settings) {
         request.transientSettings(settings);
         return this;
     }
 
     /**
+     * Sets the source containing the transient settings to be updated. They will not survive a full cluster restart
+     */
+    public ClusterUpdateSettingsRequestBuilder setTransientSettings(String settings, XContentType xContentType) {
+        request.transientSettings(settings, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the transient settings to be updated. They will not survive a full cluster restart
      */
     public ClusterUpdateSettingsRequestBuilder setTransientSettings(Map settings) {
@@ -84,13 +95,23 @@ public class ClusterUpdateSettingsRequestBuilder extends AcknowledgedRequestBuil
 
     /**
      * Sets the source containing the persistent settings to be updated. They will get applied cross restarts
+     * @deprecated use {@link #setPersistentSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public ClusterUpdateSettingsRequestBuilder setPersistentSettings(String settings) {
         request.persistentSettings(settings);
         return this;
     }
 
     /**
+     * Sets the source containing the persistent settings to be updated. They will get applied cross restarts
+     */
+    public ClusterUpdateSettingsRequestBuilder setPersistentSettings(String settings, XContentType xContentType) {
+        request.persistentSettings(settings, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the persistent settings to be updated. They will get applied cross restarts
      */
     public ClusterUpdateSettingsRequestBuilder setPersistentSettings(Map settings) {
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
index ae715050e8..3267b6d9c9 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java
@@ -288,19 +288,35 @@ public class CreateSnapshotRequest extends MasterNodeRequest<CreateSnapshotReque
     }
 
     /**
-     * Sets repository-specific snapshot settings in JSON, YAML or properties format
+     * Sets repository-specific snapshot settings in JSON or YAML format
      * <p>
      * See repository documentation for more information.
      *
      * @param source repository-specific snapshot settings
      * @return this request
+     * @deprecated use {@link #settings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public CreateSnapshotRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * Sets repository-specific snapshot settings in JSON or YAML format
+     * <p>
+     * See repository documentation for more information.
+     *
+     * @param source repository-specific snapshot settings
+     * @param xContentType the content type of the source
+     * @return this request
+     */
+    public CreateSnapshotRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Sets repository-specific snapshot settings.
      * <p>
      * See repository documentation for more information.
@@ -312,7 +328,7 @@ public class CreateSnapshotRequest extends MasterNodeRequest<CreateSnapshotReque
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
index ebdd206b5c..d3b5e12351 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequestBuilder.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Map;
 
@@ -147,13 +148,29 @@ public class CreateSnapshotRequestBuilder extends MasterNodeOperationRequestBuil
      *
      * @param source repository-specific snapshot settings
      * @return this builder
+     * @deprecated use {@link #setSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public CreateSnapshotRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
+     * Sets repository-specific snapshot settings in YAML or JSON format
+     * <p>
+     * See repository documentation for more information.
+     *
+     * @param source repository-specific snapshot settings
+     * @param xContentType the content type of the source
+     * @return this builder
+     */
+    public CreateSnapshotRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
      * Sets repository-specific snapshot settings.
      * <p>
      * See repository documentation for more information.
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
index a7bbd02ee5..9d8ed49aaa 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java
@@ -313,19 +313,35 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
     }
 
     /**
-     * Sets repository-specific restore settings in JSON, YAML or properties format
+     * Sets repository-specific restore settings in JSON or YAML format
      * <p>
      * See repository documentation for more information.
      *
      * @param source repository-specific snapshot settings
      * @return this request
+     * @deprecated use {@link #settings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public RestoreSnapshotRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * Sets repository-specific restore settings in JSON or YAML format
+     * <p>
+     * See repository documentation for more information.
+     *
+     * @param source repository-specific snapshot settings
+     * @param xContentType the content type of the source
+     * @return this request
+     */
+    public RestoreSnapshotRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Sets repository-specific restore settings
      * <p>
      * See repository documentation for more information.
@@ -337,7 +353,7 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -436,7 +452,9 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
 
     /**
      * Sets settings that should be added/changed in all restored indices
+     * @deprecated use {@link #indexSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public RestoreSnapshotRequest indexSettings(String source) {
         this.indexSettings = Settings.builder().loadFromSource(source).build();
         return this;
@@ -445,11 +463,19 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
     /**
      * Sets settings that should be added/changed in all restored indices
      */
+    public RestoreSnapshotRequest indexSettings(String source, XContentType xContentType) {
+        this.indexSettings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
+     * Sets settings that should be added/changed in all restored indices
+     */
     public RestoreSnapshotRequest indexSettings(Map<String, Object> source) {
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            indexSettings(builder.string());
+            indexSettings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
index 661a1a1d01..807e238724 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequestBuilder.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.List;
 import java.util.Map;
@@ -153,19 +154,35 @@ public class RestoreSnapshotRequestBuilder extends MasterNodeOperationRequestBui
     }
 
     /**
-     * Sets repository-specific restore settings in JSON, YAML or properties format
+     * Sets repository-specific restore settings in JSON or YAML format
      * <p>
      * See repository documentation for more information.
      *
      * @param source repository-specific snapshot settings
      * @return this builder
+     * @deprecated use {@link #setSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public RestoreSnapshotRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
+     * Sets repository-specific restore settings in JSON or YAML format
+     * <p>
+     * See repository documentation for more information.
+     *
+     * @param source repository-specific snapshot settings
+     * @param xContentType the content type of the source
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
      * Sets repository-specific restore settings
      * <p>
      * See repository documentation for more information.
@@ -251,7 +268,9 @@ public class RestoreSnapshotRequestBuilder extends MasterNodeOperationRequestBui
      *
      * @param source index settings
      * @return this builder
+     * @deprecated use {@link #setIndexSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public RestoreSnapshotRequestBuilder setIndexSettings(String source) {
         request.indexSettings(source);
         return this;
@@ -261,6 +280,18 @@ public class RestoreSnapshotRequestBuilder extends MasterNodeOperationRequestBui
      * Sets index settings that should be added or replaced during restore
      *
      * @param source index settings
+     * @param xContentType the content type of the source
+     * @return this builder
+     */
+    public RestoreSnapshotRequestBuilder setIndexSettings(String source, XContentType xContentType) {
+        request.indexSettings(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets index settings that should be added or replaced during restore
+     *
+     * @param source index settings
      * @return this builder
      */
     public RestoreSnapshotRequestBuilder setIndexSettings(Map<String, Object> source) {
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
index 0dcfe22514..28c70dc45b 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
@@ -19,14 +19,18 @@
 
 package org.elasticsearch.action.admin.cluster.storedscripts;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.support.master.AcknowledgedRequest;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
+import java.util.Objects;
 
 import static org.elasticsearch.action.ValidateActions.addValidationError;
 
@@ -35,17 +39,23 @@ public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptR
     private String id;
     private String lang;
     private BytesReference content;
+    private XContentType xContentType;
 
     public PutStoredScriptRequest() {
         super();
     }
 
+    @Deprecated
     public PutStoredScriptRequest(String id, String lang, BytesReference content) {
-        super();
+        this(id, lang, content, XContentFactory.xContentType(content));
+    }
 
+    public PutStoredScriptRequest(String id, String lang, BytesReference content, XContentType xContentType) {
+        super();
         this.id = id;
         this.lang = lang;
         this.content = content;
+        this.xContentType = Objects.requireNonNull(xContentType);
     }
 
     @Override
@@ -93,9 +103,25 @@ public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptR
         return content;
     }
 
+    public XContentType xContentType() {
+        return xContentType;
+    }
+
+    /**
+     * Set the script source using bytes.
+     * @deprecated this method is deprecated as it relies on content type detection. Use {@link #content(BytesReference, XContentType)}
+     */
+    @Deprecated
     public PutStoredScriptRequest content(BytesReference content) {
-        this.content = content;
+        return content(content, XContentFactory.xContentType(content));
+    }
 
+    /**
+     * Set the script source and the content type of the bytes.
+     */
+    public PutStoredScriptRequest content(BytesReference content, XContentType xContentType) {
+        this.content = content;
+        this.xContentType = Objects.requireNonNull(xContentType);
         return this;
     }
 
@@ -111,6 +137,11 @@ public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptR
 
         id = in.readOptionalString();
         content = in.readBytesReference();
+        if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType = XContentType.readFrom(in);
+        } else {
+            xContentType = XContentFactory.xContentType(content);
+        }
     }
 
     @Override
@@ -120,6 +151,9 @@ public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptR
         out.writeString(lang == null ? "" : lang);
         out.writeOptionalString(id);
         out.writeBytesReference(content);
+        if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType.writeTo(out);
+        }
     }
 
     @Override
@@ -127,8 +161,8 @@ public class PutStoredScriptRequest extends AcknowledgedRequest<PutStoredScriptR
         String source = "_na_";
 
         try {
-            source = XContentHelper.convertToJson(content, false);
-        } catch (Exception exception) {
+            source = XContentHelper.convertToJson(content, false, xContentType);
+        } catch (Exception e) {
             // ignore
         }
 
diff --git a/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
index b701745e47..f8223d6919 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestBuilder.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action.admin.cluster.storedscripts;
 import org.elasticsearch.action.support.master.AcknowledgedRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 
 public class PutStoredScriptRequestBuilder extends AcknowledgedRequestBuilder<PutStoredScriptRequest,
         PutStoredScriptResponse, PutStoredScriptRequestBuilder> {
@@ -32,19 +33,29 @@ public class PutStoredScriptRequestBuilder extends AcknowledgedRequestBuilder<Pu
 
     public PutStoredScriptRequestBuilder setId(String id) {
         request.id(id);
-
         return this;
     }
 
-    public PutStoredScriptRequestBuilder setLang(String lang) {
-        request.lang(lang);
-
+    /**
+     * Set the source of the script.
+     * @deprecated this method requires content type detection. Use {@link #setContent(BytesReference, XContentType)} instead
+     */
+    @Deprecated
+    public PutStoredScriptRequestBuilder setContent(BytesReference content) {
+        request.content(content);
         return this;
     }
 
-    public PutStoredScriptRequestBuilder setContent(BytesReference content) {
-        request.content(content);
+    /**
+     * Set the source of the script along with the content type of the source
+     */
+    public PutStoredScriptRequestBuilder setContent(BytesReference source, XContentType xContentType) {
+        request.content(source, xContentType);
+        return this;
+    }
 
+    public PutStoredScriptRequestBuilder setLang(String lang) {
+        request.lang(lang);
         return this;
     }
 }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/analyze/AnalyzeRequest.java b/core/src/main/java/org/elasticsearch/action/admin/indices/analyze/AnalyzeRequest.java
index 6d0824eeb3..08f220e019 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/analyze/AnalyzeRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/analyze/AnalyzeRequest.java
@@ -75,7 +75,7 @@ public class AnalyzeRequest extends SingleShardRequest<AnalyzeRequest> {
             try {
                 XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
                 builder.map(definition);
-                this.definition = Settings.builder().loadFromSource(builder.string()).build();
+                this.definition = Settings.builder().loadFromSource(builder.string(), builder.contentType()).build();
             } catch (IOException e) {
                 throw new IllegalArgumentException("Failed to parse [" + definition + "]", e);
             }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java b/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
index 203483d89b..798c08bd18 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java
@@ -21,6 +21,7 @@ package org.elasticsearch.action.admin.indices.create;
 
 import org.elasticsearch.ElasticsearchGenerationException;
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.IndicesRequest;
 import org.elasticsearch.action.admin.indices.alias.Alias;
@@ -43,10 +44,11 @@ import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
+import java.io.UncheckedIOException;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
 import static org.elasticsearch.action.ValidateActions.addValidationError;
@@ -169,19 +171,29 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
     }
 
     /**
-     * The settings to create the index with (either json/yaml/properties format)
+     * The settings to create the index with (either json or yaml format)
+     * @deprecated use {@link #source(String, XContentType)} instead to avoid content type detection
      */
+    @Deprecated
     public CreateIndexRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * The settings to create the index with (either json or yaml format)
+     */
+    public CreateIndexRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Allows to set the settings using a json builder.
      */
     public CreateIndexRequest settings(XContentBuilder builder) {
         try {
-            settings(builder.string());
+            settings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate json settings from builder", e);
         }
@@ -196,7 +208,7 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), XContentType.JSON);
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -208,13 +220,42 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
      *
      * @param type   The mapping type
      * @param source The mapping source
+     * @deprecated use {@link #mapping(String, String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public CreateIndexRequest mapping(String type, String source) {
+        return mapping(type, new BytesArray(source), XContentFactory.xContentType(source));
+    }
+
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType The content type of the source
+     */
+    public CreateIndexRequest mapping(String type, String source, XContentType xContentType) {
+        return mapping(type, new BytesArray(source), xContentType);
+    }
+
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType the content type of the mapping source
+     */
+    private CreateIndexRequest mapping(String type, BytesReference source, XContentType xContentType) {
         if (mappings.containsKey(type)) {
             throw new IllegalStateException("mappings for type \"" + type + "\" were already defined");
         }
-        mappings.put(type, source);
-        return this;
+        Objects.requireNonNull(xContentType);
+        try {
+            mappings.put(type, XContentHelper.convertToJson(source, false, false, xContentType));
+            return this;
+        } catch (IOException e) {
+            throw new UncheckedIOException("failed to convert to json", e);
+        }
     }
 
     /**
@@ -232,15 +273,7 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
      * @param source The mapping source
      */
     public CreateIndexRequest mapping(String type, XContentBuilder source) {
-        if (mappings.containsKey(type)) {
-            throw new IllegalStateException("mappings for type \"" + type + "\" were already defined");
-        }
-        try {
-            mappings.put(type, source.string());
-        } catch (IOException e) {
-            throw new IllegalArgumentException("Failed to build json for mapping request", e);
-        }
-        return this;
+        return mapping(type, source.bytes(), source.contentType());
     }
 
     /**
@@ -261,7 +294,7 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            return mapping(type, builder.string());
+            return mapping(type, builder);
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -331,9 +364,18 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
 
     /**
      * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #source(String, XContentType)}
      */
+    @Deprecated
     public CreateIndexRequest source(String source) {
-        return source(source.getBytes(StandardCharsets.UTF_8));
+        return source(new BytesArray(source));
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     */
+    public CreateIndexRequest source(String source, XContentType xContentType) {
+        return source(new BytesArray(source), xContentType);
     }
 
     /**
@@ -345,7 +387,9 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
 
     /**
      * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #source(byte[], XContentType)}
      */
+    @Deprecated
     public CreateIndexRequest source(byte[] source) {
         return source(source, 0, source.length);
     }
@@ -353,6 +397,15 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequest source(byte[] source, XContentType xContentType) {
+        return source(source, 0, source.length, xContentType);
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #source(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public CreateIndexRequest source(byte[] source, int offset, int length) {
         return source(new BytesArray(source, offset, length));
     }
@@ -360,13 +413,27 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequest source(byte[] source, int offset, int length, XContentType xContentType) {
+        return source(new BytesArray(source, offset, length), xContentType);
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #source(BytesReference, XContentType)}
+     */
+    @Deprecated
     public CreateIndexRequest source(BytesReference source) {
         XContentType xContentType = XContentFactory.xContentType(source);
-        if (xContentType != null) {
-            source(XContentHelper.convertToMap(source, false).v2());
-        } else {
-            settings(source.utf8ToString());
-        }
+        source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     */
+    public CreateIndexRequest source(BytesReference source, XContentType xContentType) {
+        Objects.requireNonNull(xContentType);
+        source(XContentHelper.convertToMap(source, false, xContentType).v2());
         return this;
     }
 
@@ -483,7 +550,13 @@ public class CreateIndexRequest extends AcknowledgedRequest<CreateIndexRequest>
         readTimeout(in);
         int size = in.readVInt();
         for (int i = 0; i < size; i++) {
-            mappings.put(in.readString(), in.readString());
+            final String type = in.readString();
+            String source = in.readString();
+            if (in.getVersion().before(Version.V_6_0_0_alpha1_UNRELEASED)) { // TODO change to 5.3.0 after backport
+                // we do not know the content type that comes from earlier versions so we autodetect and convert
+                source = XContentHelper.convertToJson(new BytesArray(source), false, false, XContentFactory.xContentType(source));
+            }
+            mappings.put(type, source);
         }
         int customSize = in.readVInt();
         for (int i = 0; i < customSize; i++) {
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilder.java
index eaae4d53b7..237c88244b 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilder.java
@@ -27,6 +27,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Map;
 
@@ -76,14 +77,24 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
     }
 
     /**
-     * The settings to create the index with (either json/yaml/properties format)
+     * The settings to create the index with (either json or yaml format)
+     * @deprecated use {@link #setSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public CreateIndexRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
+     * The settings to create the index with (either json or yaml format)
+     */
+    public CreateIndexRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
      * A simplified version of settings that takes key value pairs settings.
      */
     public CreateIndexRequestBuilder setSettings(Object... settings) {
@@ -104,13 +115,27 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
      *
      * @param type   The mapping type
      * @param source The mapping source
+     * @deprecated use {@link #addMapping(String, String, XContentType)} to avoid content type auto-detection
      */
+    @Deprecated
     public CreateIndexRequestBuilder addMapping(String type, String source) {
         request.mapping(type, source);
         return this;
     }
 
     /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType The content type of the source
+     */
+    public CreateIndexRequestBuilder addMapping(String type, String source, XContentType xContentType) {
+        request.mapping(type, source, xContentType);
+        return this;
+    }
+
+    /**
      * The cause for this index creation.
      */
     public CreateIndexRequestBuilder setCause(String cause) {
@@ -191,7 +216,9 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
 
     /**
      * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #setSource(String, XContentType)}
      */
+    @Deprecated
     public CreateIndexRequestBuilder setSource(String source) {
         request.source(source);
         return this;
@@ -200,6 +227,16 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequestBuilder setSource(String source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #setSource(BytesReference, XContentType)}
+     */
+    @Deprecated
     public CreateIndexRequestBuilder setSource(BytesReference source) {
         request.source(source);
         return this;
@@ -208,6 +245,16 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequestBuilder setSource(BytesReference source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #setSource(byte[], XContentType)}
+     */
+    @Deprecated
     public CreateIndexRequestBuilder setSource(byte[] source) {
         request.source(source);
         return this;
@@ -216,6 +263,16 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequestBuilder setSource(byte[] source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     * @deprecated use {@link #setSource(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public CreateIndexRequestBuilder setSource(byte[] source, int offset, int length) {
         request.source(source, offset, length);
         return this;
@@ -224,6 +281,14 @@ public class CreateIndexRequestBuilder extends AcknowledgedRequestBuilder<Create
     /**
      * Sets the settings and mappings as a single source.
      */
+    public CreateIndexRequestBuilder setSource(byte[] source, int offset, int length, XContentType xContentType) {
+        request.source(source, offset, length, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings and mappings as a single source.
+     */
     public CreateIndexRequestBuilder setSource(Map<String, ?> source) {
         request.source(source);
         return this;
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
index e0cedcf841..3f4ddaf08d 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
@@ -27,6 +27,7 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.Mapper;
 
 import java.io.IOException;
@@ -108,20 +109,25 @@ public class GetFieldMappingsResponse extends ActionResponse implements ToXConte
 
         /** Returns the mappings as a map. Note that the returned map has a single key which is always the field's {@link Mapper#name}. */
         public Map<String, Object> sourceAsMap() {
-            return XContentHelper.convertToMap(source, true).v2();
+            return XContentHelper.convertToMap(source, true, XContentType.JSON).v2();
         }
 
         public boolean isNull() {
             return NULL.fullName().equals(fullName) && NULL.source.length() == source.length();
         }
 
+        //pkg-private for testing
+        BytesReference getSource() {
+            return source;
+        }
+
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.field("full_name", fullName);
             if (params.paramAsBoolean("pretty", false)) {
                 builder.field("mapping", sourceAsMap());
             } else {
-                builder.rawField("mapping", source);
+                builder.rawField("mapping", source, XContentType.JSON);
             }
             return builder;
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
index 864c6703c4..ec84ce4e34 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/get/TransportGetFieldMappingsIndexAction.java
@@ -220,4 +220,4 @@ public class TransportGetFieldMappingsIndexAction extends TransportSingleShardAc
         }
     }
 
-}
-\ No newline at end of file
+}
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequest.java b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequest.java
index 152bc51654..400701f91c 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequest.java
@@ -22,19 +22,24 @@ package org.elasticsearch.action.admin.indices.mapping.put;
 import com.carrotsearch.hppc.ObjectHashSet;
 
 import org.elasticsearch.ElasticsearchGenerationException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.IndicesRequest;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.master.AcknowledgedRequest;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Objects;
@@ -245,7 +250,7 @@ public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> im
      */
     public PutMappingRequest source(XContentBuilder mappingBuilder) {
         try {
-            return source(mappingBuilder.string());
+            return source(mappingBuilder.string(), mappingBuilder.contentType());
         } catch (IOException e) {
             throw new IllegalArgumentException("Failed to build json for mapping request", e);
         }
@@ -259,7 +264,7 @@ public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> im
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(mappingSource);
-            return source(builder.string());
+            return source(builder.string(), XContentType.JSON);
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + mappingSource + "]", e);
         }
@@ -267,10 +272,31 @@ public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> im
 
     /**
      * The mapping source definition.
+     * @deprecated use {@link #source(String, XContentType)}
      */
+    @Deprecated
     public PutMappingRequest source(String mappingSource) {
-        this.source = mappingSource;
-        return this;
+        return source(mappingSource, XContentFactory.xContentType(mappingSource));
+    }
+
+    /**
+     * The mapping source definition.
+     */
+    public PutMappingRequest source(String mappingSource, XContentType xContentType) {
+        return source(new BytesArray(mappingSource), xContentType);
+    }
+
+    /**
+     * The mapping source definition.
+     */
+    public PutMappingRequest source(BytesReference mappingSource, XContentType xContentType) {
+        Objects.requireNonNull(xContentType);
+        try {
+            this.source = XContentHelper.convertToJson(mappingSource, false, false, xContentType);
+            return this;
+        } catch (IOException e) {
+            throw new UncheckedIOException("failed to convert source to json", e);
+        }
     }
 
     /** True if all fields that span multiple types should be updated, false otherwise */
@@ -291,6 +317,10 @@ public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> im
         indicesOptions = IndicesOptions.readIndicesOptions(in);
         type = in.readOptionalString();
         source = in.readString();
+        if (in.getVersion().before(Version.V_6_0_0_alpha1_UNRELEASED)) { // TODO change to V_5_3 once backported
+            // we do not know the format from earlier versions so convert if necessary
+            source = XContentHelper.convertToJson(new BytesArray(source), false, false, XContentFactory.xContentType(source));
+        }
         updateAllTypes = in.readBoolean();
         readTimeout(in);
         concreteIndex = in.readOptionalWriteable(Index::new);
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
index c21c40cf04..012a593ebc 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestBuilder.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.master.AcknowledgedRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 
 import java.util.Map;
@@ -82,13 +83,23 @@ public class PutMappingRequestBuilder extends AcknowledgedRequestBuilder<PutMapp
 
     /**
      * The mapping source definition.
+     * @deprecated use {@link #setSource(String, XContentType)}
      */
+    @Deprecated
     public PutMappingRequestBuilder setSource(String mappingSource) {
         request.source(mappingSource);
         return this;
     }
 
     /**
+     * The mapping source definition.
+     */
+    public PutMappingRequestBuilder setSource(String mappingSource, XContentType xContentType) {
+        request.source(mappingSource, xContentType);
+        return this;
+    }
+
+    /**
      * A specialized simplified mapping source method, takes the form of simple properties definition:
      * ("field1", "type=string,store=true").
      */
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequest.java b/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
index e912c6ec73..80f3fb1a07 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequest.java
@@ -121,14 +121,24 @@ public class UpdateSettingsRequest extends AcknowledgedRequest<UpdateSettingsReq
     }
 
     /**
-     * Sets the settings to be updated (either json/yaml/properties format)
+     * Sets the settings to be updated (either json or yaml format)
+     * @deprecated use {@link #settings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public UpdateSettingsRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
+     * Sets the settings to be updated (either json or yaml format)
+     */
+    public UpdateSettingsRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
      * Returns <code>true</code> iff the settings update should only add but not update settings. If the setting already exists
      * it should not be overwritten by this update. The default is <code>false</code>
      */
@@ -146,14 +156,14 @@ public class UpdateSettingsRequest extends AcknowledgedRequest<UpdateSettingsReq
     }
 
     /**
-     * Sets the settings to be updated (either json/yaml/properties format)
+     * Sets the settings to be updated (either json or yaml format)
      */
     @SuppressWarnings("unchecked")
     public UpdateSettingsRequest settings(Map source) {
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), builder.contentType());
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
index 36dfbf3b2d..a9cecbfc5a 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/settings/put/UpdateSettingsRequestBuilder.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.master.AcknowledgedRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Map;
 
@@ -70,15 +71,25 @@ public class UpdateSettingsRequestBuilder extends AcknowledgedRequestBuilder<Upd
     }
 
     /**
-     * Sets the settings to be updated (either json/yaml/properties format)
+     * Sets the settings to be updated (either json or yaml format)
+     * @deprecated use {@link #setSettings(String, XContentType)} to avoid content type detection
      */
+    @Deprecated
     public UpdateSettingsRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
-     * Sets the settings to be updated (either json/yaml/properties format)
+     * Sets the settings to be updated (either json or yaml format)
+     */
+    public UpdateSettingsRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the settings to be updated
      */
     public UpdateSettingsRequestBuilder setSettings(Map<String, Object> source) {
         request.settings(source);
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequest.java b/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
index a7d6241d31..b0c13540df 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequest.java
@@ -45,11 +45,13 @@ import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -179,21 +181,31 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
     }
 
     /**
-     * The settings to create the index template with (either json/yaml/properties format).
+     * The settings to create the index template with (either json/yaml format).
+     * @deprecated use {@link #settings(String, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequest settings(String source) {
         this.settings = Settings.builder().loadFromSource(source).build();
         return this;
     }
 
     /**
-     * The settings to crete the index template with (either json/yaml/properties format).
+     * The settings to create the index template with (either json/yaml format).
+     */
+    public PutIndexTemplateRequest settings(String source, XContentType xContentType) {
+        this.settings = Settings.builder().loadFromSource(source, xContentType).build();
+        return this;
+    }
+
+    /**
+     * The settings to create the index template with (either json or yaml format).
      */
     public PutIndexTemplateRequest settings(Map<String, Object> source) {
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            settings(builder.string());
+            settings(builder.string(), XContentType.JSON);
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -209,10 +221,23 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
      *
      * @param type   The mapping type
      * @param source The mapping source
+     * @deprecated use {@link #mapping(String, String, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequest mapping(String type, String source) {
-        mappings.put(type, source);
-        return this;
+        XContentType xContentType = XContentFactory.xContentType(source);
+        return mapping(type, source, xContentType);
+    }
+
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType The type of content contained within the source
+     */
+    public PutIndexTemplateRequest mapping(String type, String source, XContentType xContentType) {
+        return mapping(type, new BytesArray(source), xContentType);
     }
 
     /**
@@ -234,12 +259,24 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
      * @param source The mapping source
      */
     public PutIndexTemplateRequest mapping(String type, XContentBuilder source) {
+        return mapping(type, source.bytes(), source.contentType());
+    }
+
+    /**
+     * Adds mapping that will be added when the index gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType the source content type
+     */
+    public PutIndexTemplateRequest mapping(String type, BytesReference source, XContentType xContentType) {
+        Objects.requireNonNull(xContentType);
         try {
-            mappings.put(type, source.string());
+            mappings.put(type, XContentHelper.convertToJson(source, false, false, xContentType));
+            return this;
         } catch (IOException e) {
-            throw new IllegalArgumentException("Failed to build json for mapping request", e);
+            throw new UncheckedIOException("failed to convert source to json", e);
         }
-        return this;
     }
 
     /**
@@ -256,7 +293,7 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
         try {
             XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
             builder.map(source);
-            return mapping(type, builder.string());
+            return mapping(type, builder);
         } catch (IOException e) {
             throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
         }
@@ -280,7 +317,7 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
      */
     public PutIndexTemplateRequest source(XContentBuilder templateBuilder) {
         try {
-            return source(templateBuilder.bytes());
+            return source(templateBuilder.bytes(), templateBuilder.contentType());
         } catch (Exception e) {
             throw new IllegalArgumentException("Failed to build json for template request", e);
         }
@@ -350,7 +387,9 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
 
     /**
      * The template source definition.
+     * @deprecated use {@link #source(String, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequest source(String templateSource) {
         return source(XContentHelper.convertToMap(XContentFactory.xContent(templateSource), templateSource, true));
     }
@@ -358,6 +397,15 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(String templateSource, XContentType xContentType) {
+        return source(XContentHelper.convertToMap(xContentType.xContent(), templateSource, true));
+    }
+
+    /**
+     * The template source definition.
+     * @deprecated use {@link #source(byte[], XContentType)}
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(byte[] source) {
         return source(source, 0, source.length);
     }
@@ -365,6 +413,15 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(byte[] source, XContentType xContentType) {
+        return source(source, 0, source.length, xContentType);
+    }
+
+    /**
+     * The template source definition.
+     * @deprecated use {@link #source(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(byte[] source, int offset, int length) {
         return source(new BytesArray(source, offset, length));
     }
@@ -372,10 +429,26 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequest source(byte[] source, int offset, int length, XContentType xContentType) {
+        return source(new BytesArray(source, offset, length), xContentType);
+    }
+
+    /**
+     * The template source definition.
+     * @deprecated use {@link #source(BytesReference, XContentType)}
+     */
+    @Deprecated
     public PutIndexTemplateRequest source(BytesReference source) {
         return source(XContentHelper.convertToMap(source, true).v2());
     }
 
+    /**
+     * The template source definition.
+     */
+    public PutIndexTemplateRequest source(BytesReference source, XContentType xContentType) {
+        return source(XContentHelper.convertToMap(source, true, xContentType).v2());
+    }
+
     public PutIndexTemplateRequest custom(IndexMetaData.Custom custom) {
         customs.put(custom.type(), custom);
         return this;
@@ -471,7 +544,14 @@ public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateR
         settings = readSettingsFromStream(in);
         int size = in.readVInt();
         for (int i = 0; i < size; i++) {
-            mappings.put(in.readString(), in.readString());
+            final String type = in.readString();
+            String mappingSource = in.readString();
+            if (in.getVersion().before(Version.V_6_0_0_alpha1_UNRELEASED)) { // TODO change to V_5_3_0 once backported
+                // we do not know the incoming type so convert it if needed
+                mappingSource =
+                    XContentHelper.convertToJson(new BytesArray(mappingSource), false, false, XContentFactory.xContentType(mappingSource));
+            }
+            mappings.put(type, mappingSource);
         }
         int customSize = in.readVInt();
         for (int i = 0; i < customSize; i++) {
diff --git a/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
index c1db96ae7c..e7ca25e511 100644
--- a/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java
@@ -24,6 +24,7 @@ import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.util.Collections;
 import java.util.List;
@@ -100,15 +101,25 @@ public class PutIndexTemplateRequestBuilder
     }
 
     /**
-     * The settings to crete the index template with (either json/yaml/properties format)
+     * The settings to crete the index template with (either json or yaml format)
+     * @deprecated use {@link #setSettings(String, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequestBuilder setSettings(String source) {
         request.settings(source);
         return this;
     }
 
     /**
-     * The settings to crete the index template with (either json/yaml/properties format)
+     * The settings to crete the index template with (either json or yaml format)
+     */
+    public PutIndexTemplateRequestBuilder setSettings(String source, XContentType xContentType) {
+        request.settings(source, xContentType);
+        return this;
+    }
+
+    /**
+     * The settings to crete the index template with (either json or yaml format)
      */
     public PutIndexTemplateRequestBuilder setSettings(Map<String, Object> source) {
         request.settings(source);
@@ -120,13 +131,27 @@ public class PutIndexTemplateRequestBuilder
      *
      * @param type   The mapping type
      * @param source The mapping source
+     * @deprecated use {@link #addMapping(String, String, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequestBuilder addMapping(String type, String source) {
         request.mapping(type, source);
         return this;
     }
 
     /**
+     * Adds mapping that will be added when the index template gets created.
+     *
+     * @param type   The mapping type
+     * @param source The mapping source
+     * @param xContentType The type/format of the source
+     */
+    public PutIndexTemplateRequestBuilder addMapping(String type, String source, XContentType xContentType) {
+        request.mapping(type, source, xContentType);
+        return this;
+    }
+
+    /**
      * A specialized simplified mapping source method, takes the form of simple properties definition:
      * ("field1", "type=string,store=true").
      */
@@ -226,7 +251,9 @@ public class PutIndexTemplateRequestBuilder
 
     /**
      * The template source definition.
+     * @deprecated use {@link #setSource(BytesReference, XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequestBuilder setSource(String templateSource) {
         request.source(templateSource);
         return this;
@@ -235,6 +262,16 @@ public class PutIndexTemplateRequestBuilder
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequestBuilder setSource(BytesReference templateSource, XContentType xContentType) {
+        request.source(templateSource, xContentType);
+        return this;
+    }
+
+    /**
+     * The template source definition.
+     * @deprecated use {@link #setSource(BytesReference, XContentType)}
+     */
+    @Deprecated
     public PutIndexTemplateRequestBuilder setSource(BytesReference templateSource) {
         request.source(templateSource);
         return this;
@@ -242,7 +279,9 @@ public class PutIndexTemplateRequestBuilder
 
     /**
      * The template source definition.
+     * @deprecated use {@link #setSource(byte[], XContentType)}
      */
+    @Deprecated
     public PutIndexTemplateRequestBuilder setSource(byte[] templateSource) {
         request.source(templateSource);
         return this;
@@ -251,8 +290,26 @@ public class PutIndexTemplateRequestBuilder
     /**
      * The template source definition.
      */
+    public PutIndexTemplateRequestBuilder setSource(byte[] templateSource, XContentType xContentType) {
+        request.source(templateSource, xContentType);
+        return this;
+    }
+
+    /**
+     * The template source definition.
+     * @deprecated use {@link #setSource(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public PutIndexTemplateRequestBuilder setSource(byte[] templateSource, int offset, int length) {
         request.source(templateSource, offset, length);
         return this;
     }
+
+    /**
+     * The template source definition.
+     */
+    public PutIndexTemplateRequestBuilder setSource(byte[] templateSource, int offset, int length, XContentType xContentType) {
+        request.source(templateSource, offset, length, xContentType);
+        return this;
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/action/bulk/BulkRequest.java b/core/src/main/java/org/elasticsearch/action/bulk/BulkRequest.java
index 20d5e64f49..371659586f 100644
--- a/core/src/main/java/org/elasticsearch/action/bulk/BulkRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/bulk/BulkRequest.java
@@ -43,6 +43,7 @@ import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContent;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 
@@ -244,7 +245,9 @@ public class BulkRequest extends ActionRequest implements CompositeIndicesReques
 
     /**
      * Adds a framed data in binary format
+     * @deprecated use {@link #add(byte[], int, int, XContentType)}
      */
+    @Deprecated
     public BulkRequest add(byte[] data, int from, int length) throws IOException {
         return add(data, from, length, null, null);
     }
@@ -252,6 +255,15 @@ public class BulkRequest extends ActionRequest implements CompositeIndicesReques
     /**
      * Adds a framed data in binary format
      */
+    public BulkRequest add(byte[] data, int from, int length, XContentType xContentType) throws IOException {
+        return add(data, from, length, null, null, xContentType);
+    }
+
+    /**
+     * Adds a framed data in binary format
+     * @deprecated use {@link #add(byte[], int, int, String, String, XContentType)}
+     */
+    @Deprecated
     public BulkRequest add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType) throws IOException {
         return add(new BytesArray(data, from, length), defaultIndex, defaultType);
     }
@@ -259,6 +271,17 @@ public class BulkRequest extends ActionRequest implements CompositeIndicesReques
     /**
      * Adds a framed data in binary format
      */
+    public BulkRequest add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType,
+                           XContentType xContentType) throws IOException {
+        return add(new BytesArray(data, from, length), defaultIndex, defaultType, xContentType);
+    }
+
+    /**
+     * Adds a framed data in binary format
+     *
+     * @deprecated use {@link #add(BytesReference, String, String, XContentType)}
+     */
+    @Deprecated
     public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType) throws IOException {
         return add(data, defaultIndex, defaultType, null, null, null, null, null, true);
     }
@@ -266,12 +289,40 @@ public class BulkRequest extends ActionRequest implements CompositeIndicesReques
     /**
      * Adds a framed data in binary format
      */
+    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType,
+                           XContentType xContentType) throws IOException {
+        return add(data, defaultIndex, defaultType, null, null, null, null, null, true, xContentType);
+    }
+
+    /**
+     * Adds a framed data in binary format
+     *
+     * @deprecated use {@link #add(BytesReference, String, String, boolean, XContentType)}
+     */
+    @Deprecated
     public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType, boolean allowExplicitIndex) throws IOException {
         return add(data, defaultIndex, defaultType, null, null, null, null, null, allowExplicitIndex);
     }
 
+    /**
+     * Adds a framed data in binary format
+     */
+    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType, boolean allowExplicitIndex,
+                           XContentType xContentType) throws IOException {
+        return add(data, defaultIndex, defaultType, null, null, null, null, null, allowExplicitIndex, xContentType);
+    }
+
+    @Deprecated
     public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType, @Nullable String defaultRouting, @Nullable String[] defaultFields, @Nullable FetchSourceContext defaultFetchSourceContext, @Nullable String defaultPipeline, @Nullable Object payload, boolean allowExplicitIndex) throws IOException {
-        XContent xContent = XContentFactory.xContent(data);
+        XContentType xContentType = XContentFactory.xContentType(data);
+        return add(data, defaultIndex, defaultType, defaultRouting, defaultFields, defaultFetchSourceContext, defaultPipeline, payload,
+            allowExplicitIndex, xContentType);
+    }
+
+    public BulkRequest add(BytesReference data, @Nullable String defaultIndex, @Nullable String defaultType, @Nullable String
+        defaultRouting, @Nullable String[] defaultFields, @Nullable FetchSourceContext defaultFetchSourceContext, @Nullable String
+        defaultPipeline, @Nullable Object payload, boolean allowExplicitIndex, XContentType xContentType) throws IOException {
+        XContent xContent = xContentType.xContent();
         int line = 0;
         int from = 0;
         int length = data.length();
@@ -387,16 +438,16 @@ public class BulkRequest extends ActionRequest implements CompositeIndicesReques
                     if ("index".equals(action)) {
                         if (opType == null) {
                             internalAdd(new IndexRequest(index, type, id).routing(routing).parent(parent).version(version).versionType(versionType)
-                                    .setPipeline(pipeline).source(data.slice(from, nextMarker - from)), payload);
+                                    .setPipeline(pipeline).source(data.slice(from, nextMarker - from), xContentType), payload);
                         } else {
                             internalAdd(new IndexRequest(index, type, id).routing(routing).parent(parent).version(version).versionType(versionType)
                                     .create("create".equals(opType)).setPipeline(pipeline)
-                                    .source(data.slice(from, nextMarker - from)), payload);
+                                    .source(data.slice(from, nextMarker - from), xContentType), payload);
                         }
                     } else if ("create".equals(action)) {
                         internalAdd(new IndexRequest(index, type, id).routing(routing).parent(parent).version(version).versionType(versionType)
                                 .create(true).setPipeline(pipeline)
-                                .source(data.slice(from, nextMarker - from)), payload);
+                                .source(data.slice(from, nextMarker - from), xContentType), payload);
                     } else if ("update".equals(action)) {
                         UpdateRequest updateRequest = new UpdateRequest(index, type, id).routing(routing).parent(parent).retryOnConflict(retryOnConflict)
                                 .version(version).versionType(versionType)
diff --git a/core/src/main/java/org/elasticsearch/action/bulk/BulkRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/bulk/BulkRequestBuilder.java
index c48a8f507b..8f634fa28a 100644
--- a/core/src/main/java/org/elasticsearch/action/bulk/BulkRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/bulk/BulkRequestBuilder.java
@@ -32,6 +32,7 @@ import org.elasticsearch.action.update.UpdateRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 
 /**
  * A bulk request holds an ordered {@link IndexRequest}s and {@link DeleteRequest}s and allows to executes
@@ -97,7 +98,9 @@ public class BulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkRe
 
     /**
      * Adds a framed data in binary format
+     * @deprecated use {@link #add(byte[], int, int, XContentType)}
      */
+    @Deprecated
     public BulkRequestBuilder add(byte[] data, int from, int length) throws Exception {
         request.add(data, from, length, null, null);
         return this;
@@ -106,12 +109,31 @@ public class BulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkRe
     /**
      * Adds a framed data in binary format
      */
+    public BulkRequestBuilder add(byte[] data, int from, int length, XContentType xContentType) throws Exception {
+        request.add(data, from, length, null, null, xContentType);
+        return this;
+    }
+
+    /**
+     * Adds a framed data in binary format
+     * @deprecated use {@link #add(byte[], int, int, String, String, XContentType)}
+     */
+    @Deprecated
     public BulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType) throws Exception {
         request.add(data, from, length, defaultIndex, defaultType);
         return this;
     }
 
     /**
+     * Adds a framed data in binary format
+     */
+    public BulkRequestBuilder add(byte[] data, int from, int length, @Nullable String defaultIndex, @Nullable String defaultType,
+                                  XContentType xContentType) throws Exception {
+        request.add(data, from, length, defaultIndex, defaultType, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the number of shard copies that must be active before proceeding with the write.
      * See {@link ReplicationRequest#waitForActiveShards(ActiveShardCount)} for details.
      */
diff --git a/core/src/main/java/org/elasticsearch/action/bulk/TransportShardBulkAction.java b/core/src/main/java/org/elasticsearch/action/bulk/TransportShardBulkAction.java
index 12981664c2..f5faa18403 100644
--- a/core/src/main/java/org/elasticsearch/action/bulk/TransportShardBulkAction.java
+++ b/core/src/main/java/org/elasticsearch/action/bulk/TransportShardBulkAction.java
@@ -328,7 +328,7 @@ public class TransportShardBulkAction extends TransportWriteAction<BulkShardRequ
                         if ((updateRequest.fetchSource() != null && updateRequest.fetchSource().fetchSource()) ||
                             (updateRequest.fields() != null && updateRequest.fields().length > 0)) {
                             Tuple<XContentType, Map<String, Object>> sourceAndContent =
-                                XContentHelper.convertToMap(indexSourceAsBytes, true);
+                                XContentHelper.convertToMap(indexSourceAsBytes, true, updateIndexRequest.getContentType());
                             updateResponse.setGetResult(updateHelper.extractGetResult(updateRequest, request.index(),
                                 indexResponse.getVersion(), sourceAndContent.v2(), sourceAndContent.v1(), indexSourceAsBytes));
                         }
@@ -427,8 +427,9 @@ public class TransportShardBulkAction extends TransportWriteAction<BulkShardRequ
      */
     public static Engine.IndexResult executeIndexRequestOnReplica(IndexRequest request, IndexShard replica) throws IOException {
         final ShardId shardId = replica.shardId();
-        SourceToParse sourceToParse = SourceToParse.source(SourceToParse.Origin.REPLICA, shardId.getIndexName(), request.type(), request.id(), request.source())
-                .routing(request.routing()).parent(request.parent());
+        SourceToParse sourceToParse =
+            SourceToParse.source(SourceToParse.Origin.REPLICA, shardId.getIndexName(), request.type(), request.id(), request.source(),
+                request.getContentType()).routing(request.routing()).parent(request.parent());
 
         final Engine.Index operation;
         try {
@@ -445,8 +446,9 @@ public class TransportShardBulkAction extends TransportWriteAction<BulkShardRequ
 
     /** Utility method to prepare an index operation on primary shards */
     static Engine.Index prepareIndexOperationOnPrimary(IndexRequest request, IndexShard primary) {
-        SourceToParse sourceToParse = SourceToParse.source(SourceToParse.Origin.PRIMARY, request.index(), request.type(), request.id(), request.source())
-                .routing(request.routing()).parent(request.parent());
+        SourceToParse sourceToParse =
+            SourceToParse.source(SourceToParse.Origin.PRIMARY, request.index(), request.type(), request.id(), request.source(),
+                request.getContentType()).routing(request.routing()).parent(request.parent());
         return primary.prepareIndexOnPrimary(sourceToParse, request.version(), request.versionType(), request.getAutoGeneratedTimestamp(), request.isRetry());
     }
 
diff --git a/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ClientScrollableHitSource.java b/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ClientScrollableHitSource.java
index 8831b2f636..4f2aefc101 100644
--- a/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ClientScrollableHitSource.java
+++ b/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ClientScrollableHitSource.java
@@ -37,6 +37,8 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
 import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.ParentFieldMapper;
 import org.elasticsearch.index.mapper.RoutingFieldMapper;
 import org.elasticsearch.search.SearchHit;
@@ -233,6 +235,10 @@ public class ClientScrollableHitSource extends ScrollableHitSource {
         }
 
         @Override
+        public XContentType getXContentType() {
+            return XContentFactory.xContentType(source);
+        }
+        @Override
         public long getVersion() {
             return delegate.getVersion();
         }
diff --git a/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ScrollableHitSource.java b/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ScrollableHitSource.java
index 8b8a350ffd..73aa653698 100644
--- a/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ScrollableHitSource.java
+++ b/core/src/main/java/org/elasticsearch/action/bulk/byscroll/ScrollableHitSource.java
@@ -32,6 +32,7 @@ import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.threadpool.ThreadPool;
 
@@ -80,7 +81,7 @@ public abstract class ScrollableHitSource implements Closeable {
         });
     }
     protected abstract void doStartNextScroll(String scrollId, TimeValue extraKeepAlive, Consumer<? super Response> onResponse);
-    
+
     @Override
     public final void close() {
         String scrollId = this.scrollId.get();
@@ -190,6 +191,10 @@ public abstract class ScrollableHitSource implements Closeable {
          */
         @Nullable BytesReference getSource();
         /**
+         * The content type of the hit source. Returns null if the source didn't come back from the search.
+         */
+        @Nullable XContentType getXContentType();
+        /**
          * The document id of the parent of the hit if there is a parent or null if there isn't.
          */
         @Nullable String getParent();
@@ -209,6 +214,7 @@ public abstract class ScrollableHitSource implements Closeable {
         private final long version;
 
         private BytesReference source;
+        private XContentType xContentType;
         private String parent;
         private String routing;
 
@@ -244,8 +250,14 @@ public abstract class ScrollableHitSource implements Closeable {
             return source;
         }
 
-        public BasicHit setSource(BytesReference source) {
+        @Override
+        public XContentType getXContentType() {
+            return xContentType;
+        }
+
+        public BasicHit setSource(BytesReference source, XContentType xContentType) {
             this.source = source;
+            this.xContentType = xContentType;
             return this;
         }
 
diff --git a/core/src/main/java/org/elasticsearch/action/index/IndexRequest.java b/core/src/main/java/org/elasticsearch/action/index/IndexRequest.java
index d1a9927c67..7e3f14368d 100644
--- a/core/src/main/java/org/elasticsearch/action/index/IndexRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/index/IndexRequest.java
@@ -47,6 +47,7 @@ import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 
 import static org.elasticsearch.action.ValidateActions.addValidationError;
 
@@ -55,10 +56,10 @@ import static org.elasticsearch.action.ValidateActions.addValidationError;
  * created using {@link org.elasticsearch.client.Requests#indexRequest(String)}.
  *
  * The index requires the {@link #index()}, {@link #type(String)}, {@link #id(String)} and
- * {@link #source(byte[])} to be set.
+ * {@link #source(byte[], XContentType)} to be set.
  *
- * The source (content to index) can be set in its bytes form using ({@link #source(byte[])}),
- * its string form ({@link #source(String)}) or using a {@link org.elasticsearch.common.xcontent.XContentBuilder}
+ * The source (content to index) can be set in its bytes form using ({@link #source(byte[], XContentType)}),
+ * its string form ({@link #source(String, XContentType)}) or using a {@link org.elasticsearch.common.xcontent.XContentBuilder}
  * ({@link #source(org.elasticsearch.common.xcontent.XContentBuilder)}).
  *
  * If the {@link #id(String)} is not set, it will be automatically generated.
@@ -83,7 +84,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
     private long version = Versions.MATCH_ANY;
     private VersionType versionType = VersionType.INTERNAL;
 
-    private XContentType contentType = Requests.INDEX_CONTENT_TYPE;
+    private XContentType contentType;
 
     private String pipeline;
 
@@ -103,7 +104,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
 
     /**
      * Constructs a new index request against the specific index. The {@link #type(String)}
-     * {@link #source(byte[])} must be set.
+     * {@link #source(byte[], XContentType)} must be set.
      */
     public IndexRequest(String index) {
         this.index = index;
@@ -140,7 +141,9 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
         if (source == null) {
             validationException = addValidationError("source is missing", validationException);
         }
-
+        if (contentType == null) {
+            validationException = addValidationError("content type is missing", validationException);
+        }
         final long resolvedVersion = resolveVersionDefaults();
         if (opType() == OpType.CREATE) {
             if (versionType != VersionType.INTERNAL) {
@@ -179,21 +182,14 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
     }
 
     /**
-     * The content type that will be used when generating a document from user provided objects like Maps.
+     * The content type. This will be used when generating a document from user provided objects like Maps and when parsing the
+     * source at index time
      */
     public XContentType getContentType() {
         return contentType;
     }
 
     /**
-     * Sets the content type that will be used when generating a document from user provided objects (like Map).
-     */
-    public IndexRequest contentType(XContentType contentType) {
-        this.contentType = contentType;
-        return this;
-    }
-
-    /**
      * The type of the indexed document.
      */
     @Override
@@ -284,16 +280,16 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
     }
 
     public Map<String, Object> sourceAsMap() {
-        return XContentHelper.convertToMap(source, false).v2();
+        return XContentHelper.convertToMap(source, false, contentType).v2();
     }
 
     /**
-     * Index the Map as a {@link org.elasticsearch.client.Requests#INDEX_CONTENT_TYPE}.
+     * Index the Map in {@link Requests#INDEX_CONTENT_TYPE} format
      *
      * @param source The map to index
      */
     public IndexRequest source(Map source) throws ElasticsearchGenerationException {
-        return source(source, contentType);
+        return source(source, Requests.INDEX_CONTENT_TYPE);
     }
 
     /**
@@ -314,24 +310,32 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
     /**
      * Sets the document source to index.
      *
-     * Note, its preferable to either set it using {@link #source(org.elasticsearch.common.xcontent.XContentBuilder)}
-     * or using the {@link #source(byte[])}.
+     * @deprecated use {@link #source(String, XContentType)}
      */
+    @Deprecated
     public IndexRequest source(String source) {
-        this.source = new BytesArray(source.getBytes(StandardCharsets.UTF_8));
-        return this;
+        return source(new BytesArray(source), XContentFactory.xContentType(source));
+    }
+
+    /**
+     * Sets the document source to index.
+     *
+     * Note, its preferable to either set it using {@link #source(org.elasticsearch.common.xcontent.XContentBuilder)}
+     * or using the {@link #source(byte[], XContentType)}.
+     */
+    public IndexRequest source(String source, XContentType xContentType) {
+        return source(new BytesArray(source), xContentType);
     }
 
     /**
      * Sets the content source to index.
      */
     public IndexRequest source(XContentBuilder sourceBuilder) {
-        source = sourceBuilder.bytes();
-        return this;
+        return source(sourceBuilder.bytes(), sourceBuilder.contentType());
     }
 
     /**
-     * Sets the content source to index.
+     * Sets the content source to index using the default content type ({@link Requests#INDEX_CONTENT_TYPE})
      * <p>
      * <b>Note: the number of objects passed to this method must be an even
      * number. Also the first argument in each pair (the field name) must have a
@@ -339,6 +343,18 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
      * </p>
      */
     public IndexRequest source(Object... source) {
+        return source(Requests.INDEX_CONTENT_TYPE, source);
+    }
+
+    /**
+     * Sets the content source to index.
+     * <p>
+     * <b>Note: the number of objects passed to this method as varargs must be an even
+     * number. Also the first argument in each pair (the field name) must have a
+     * valid String representation.</b>
+     * </p>
+     */
+    public IndexRequest source(XContentType xContentType, Object... source) {
         if (source.length % 2 != 0) {
             throw new IllegalArgumentException("The number of object passed must be even but was [" + source.length + "]");
         }
@@ -346,7 +362,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
             throw new IllegalArgumentException("you are using the removed method for source with bytes and unsafe flag, the unsafe flag was removed, please just use source(BytesReference)");
         }
         try {
-            XContentBuilder builder = XContentFactory.contentBuilder(contentType);
+            XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
             builder.startObject();
             for (int i = 0; i < source.length; i++) {
                 builder.field(source[i++].toString(), source[i]);
@@ -360,30 +376,63 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
 
     /**
      * Sets the document to index in bytes form.
+     * @deprecated use {@link #source(BytesReference, XContentType)}
      */
+    @Deprecated
     public IndexRequest source(BytesReference source) {
-        this.source = source;
+        return source(source, XContentFactory.xContentType(source));
+
+    }
+
+    /**
+     * Sets the document to index in bytes form.
+     */
+    public IndexRequest source(BytesReference source, XContentType xContentType) {
+        this.source = Objects.requireNonNull(source);
+        this.contentType = Objects.requireNonNull(xContentType);
         return this;
     }
 
     /**
      * Sets the document to index in bytes form.
+     * @deprecated use {@link #source(byte[], XContentType)}
      */
+    @Deprecated
     public IndexRequest source(byte[] source) {
         return source(source, 0, source.length);
     }
 
     /**
+     * Sets the document to index in bytes form.
+     */
+    public IndexRequest source(byte[] source, XContentType xContentType) {
+        return source(source, 0, source.length, xContentType);
+    }
+
+    /**
      * Sets the document to index in bytes form (assumed to be safe to be used from different
      * threads).
      *
      * @param source The source to index
      * @param offset The offset in the byte array
      * @param length The length of the data
+     * @deprecated use {@link #source(byte[], int, int, XContentType)}
      */
+    @Deprecated
     public IndexRequest source(byte[] source, int offset, int length) {
-        this.source = new BytesArray(source, offset, length);
-        return this;
+        return source(new BytesArray(source, offset, length), XContentFactory.xContentType(source));
+    }
+
+    /**
+     * Sets the document to index in bytes form (assumed to be safe to be used from different
+     * threads).
+     *
+     * @param source The source to index
+     * @param offset The offset in the byte array
+     * @param length The length of the data
+     */
+    public IndexRequest source(byte[] source, int offset, int length, XContentType xContentType) {
+        return source(new BytesArray(source, offset, length), xContentType);
     }
 
     /**
@@ -515,6 +564,11 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
         pipeline = in.readOptionalString();
         isRetry = in.readBoolean();
         autoGeneratedTimestamp = in.readLong();
+        if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            contentType = in.readOptionalWriteable(XContentType::readFrom);
+        } else {
+            contentType = XContentFactory.xContentType(source);
+        }
     }
 
     @Override
@@ -543,6 +597,9 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
         out.writeOptionalString(pipeline);
         out.writeBoolean(isRetry);
         out.writeLong(autoGeneratedTimestamp);
+        if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            out.writeOptionalWriteable(contentType);
+        }
     }
 
     @Override
diff --git a/core/src/main/java/org/elasticsearch/action/index/IndexRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/index/IndexRequestBuilder.java
index f7df8bffce..7af43ec35e 100644
--- a/core/src/main/java/org/elasticsearch/action/index/IndexRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/index/IndexRequestBuilder.java
@@ -82,13 +82,23 @@ public class IndexRequestBuilder extends ReplicationRequestBuilder<IndexRequest,
 
     /**
      * Sets the source.
+     * @deprecated use {@link #setSource(BytesReference, XContentType)}
      */
+    @Deprecated
     public IndexRequestBuilder setSource(BytesReference source) {
         request.source(source);
         return this;
     }
 
     /**
+     * Sets the source.
+     */
+    public IndexRequestBuilder setSource(BytesReference source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
      * Index the Map as a JSON.
      *
      * @param source The map to index
@@ -112,14 +122,27 @@ public class IndexRequestBuilder extends ReplicationRequestBuilder<IndexRequest,
      * Sets the document source to index.
      * <p>
      * Note, its preferable to either set it using {@link #setSource(org.elasticsearch.common.xcontent.XContentBuilder)}
-     * or using the {@link #setSource(byte[])}.
+     * or using the {@link #setSource(byte[], XContentType)}.
+     * @deprecated use {@link #setSource(String, XContentType)}
      */
+    @Deprecated
     public IndexRequestBuilder setSource(String source) {
         request.source(source);
         return this;
     }
 
     /**
+     * Sets the document source to index.
+     * <p>
+     * Note, its preferable to either set it using {@link #setSource(org.elasticsearch.common.xcontent.XContentBuilder)}
+     * or using the {@link #setSource(byte[], XContentType)}.
+     */
+    public IndexRequestBuilder setSource(String source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the content source to index.
      */
     public IndexRequestBuilder setSource(XContentBuilder sourceBuilder) {
@@ -129,26 +152,52 @@ public class IndexRequestBuilder extends ReplicationRequestBuilder<IndexRequest,
 
     /**
      * Sets the document to index in bytes form.
+     * @deprecated use {@link #setSource(byte[], XContentType)}
      */
+    @Deprecated
     public IndexRequestBuilder setSource(byte[] source) {
         request.source(source);
         return this;
     }
 
     /**
+     * Sets the document to index in bytes form.
+     */
+    public IndexRequestBuilder setSource(byte[] source, XContentType xContentType) {
+        request.source(source, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the document to index in bytes form (assumed to be safe to be used from different
      * threads).
      *
      * @param source The source to index
      * @param offset The offset in the byte array
      * @param length The length of the data
+     * @deprecated use {@link #setSource(byte[], int, int, XContentType)}
      */
+    @Deprecated
     public IndexRequestBuilder setSource(byte[] source, int offset, int length) {
         request.source(source, offset, length);
         return this;
     }
 
     /**
+     * Sets the document to index in bytes form (assumed to be safe to be used from different
+     * threads).
+     *
+     * @param source The source to index
+     * @param offset The offset in the byte array
+     * @param length The length of the data
+     * @param xContentType The type/format of the source
+     */
+    public IndexRequestBuilder setSource(byte[] source, int offset, int length, XContentType xContentType) {
+        request.source(source, offset, length, xContentType);
+        return this;
+    }
+
+    /**
      * Constructs a simple document with a field name and value pairs.
      * <p>
      * <b>Note: the number of objects passed to this method must be an even
@@ -162,10 +211,15 @@ public class IndexRequestBuilder extends ReplicationRequestBuilder<IndexRequest,
     }
 
     /**
-     * The content type that will be used to generate a document from user provided objects (like Map).
+     * Constructs a simple document with a field name and value pairs.
+     * <p>
+     * <b>Note: the number of objects passed as varargs to this method must be an even
+     * number. Also the first argument in each pair (the field name) must have a
+     * valid String representation.</b>
+     * </p>
      */
-    public IndexRequestBuilder setContentType(XContentType contentType) {
-        request.contentType(contentType);
+    public IndexRequestBuilder setSource(XContentType xContentType, Object... source) {
+        request.source(xContentType, source);
         return this;
     }
 
diff --git a/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequest.java b/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequest.java
index 10416146ba..a28950b24c 100644
--- a/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequest.java
@@ -19,32 +19,40 @@
 
 package org.elasticsearch.action.ingest;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.support.master.AcknowledgedRequest;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.util.Objects;
 
-import static org.elasticsearch.action.ValidateActions.addValidationError;
-
 public class PutPipelineRequest extends AcknowledgedRequest<PutPipelineRequest> {
 
     private String id;
     private BytesReference source;
+    private XContentType xContentType;
 
+    /**
+     * Create a new pipeline request
+     * @deprecated use {@link #PutPipelineRequest(String, BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     public PutPipelineRequest(String id, BytesReference source) {
-        if (id == null) {
-            throw new IllegalArgumentException("id is missing");
-        }
-        if (source == null) {
-            throw new IllegalArgumentException("source is missing");
-        }
+        this(id, source, XContentFactory.xContentType(source));
+    }
 
-        this.id = id;
-        this.source = source;
+    /**
+     * Create a new pipeline request with the id and source along with the content type of the source
+     */
+    public PutPipelineRequest(String id, BytesReference source, XContentType xContentType) {
+        this.id = Objects.requireNonNull(id);
+        this.source = Objects.requireNonNull(source);
+        this.xContentType = Objects.requireNonNull(xContentType);
     }
 
     PutPipelineRequest() {
@@ -63,11 +71,20 @@ public class PutPipelineRequest extends AcknowledgedRequest<PutPipelineRequest>
         return source;
     }
 
+    public XContentType getXContentType() {
+        return xContentType;
+    }
+
     @Override
     public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
         id = in.readString();
         source = in.readBytesReference();
+        if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType = XContentType.readFrom(in);
+        } else {
+            xContentType = XContentFactory.xContentType(source);
+        }
     }
 
     @Override
@@ -75,5 +92,8 @@ public class PutPipelineRequest extends AcknowledgedRequest<PutPipelineRequest>
         super.writeTo(out);
         out.writeString(id);
         out.writeBytesReference(source);
+        if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType.writeTo(out);
+        }
     }
 }
diff --git a/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequestBuilder.java
index bd927115fb..c03b3b84f8 100644
--- a/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/ingest/PutPipelineRequestBuilder.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action.ingest;
 import org.elasticsearch.action.ActionRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 
 public class PutPipelineRequestBuilder extends ActionRequestBuilder<PutPipelineRequest, WritePipelineResponse, PutPipelineRequestBuilder> {
 
@@ -29,8 +30,13 @@ public class PutPipelineRequestBuilder extends ActionRequestBuilder<PutPipelineR
         super(client, action, new PutPipelineRequest());
     }
 
+    @Deprecated
     public PutPipelineRequestBuilder(ElasticsearchClient client, PutPipelineAction action, String id, BytesReference source) {
         super(client, action, new PutPipelineRequest(id, source));
     }
 
+    public PutPipelineRequestBuilder(ElasticsearchClient client, PutPipelineAction action, String id, BytesReference source,
+                                     XContentType xContentType) {
+        super(client, action, new PutPipelineRequest(id, source, xContentType));
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequest.java b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequest.java
index ef7b5e3d5b..362d2e7ab9 100644
--- a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequest.java
@@ -19,11 +19,14 @@
 
 package org.elasticsearch.action.ingest;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequest;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.ingest.ConfigurationUtils;
 import org.elasticsearch.ingest.IngestDocument;
 import org.elasticsearch.ingest.Pipeline;
@@ -34,6 +37,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 import static org.elasticsearch.ingest.IngestDocument.MetaData;
 
@@ -42,12 +46,23 @@ public class SimulatePipelineRequest extends ActionRequest {
     private String id;
     private boolean verbose;
     private BytesReference source;
+    private XContentType xContentType;
 
+    /**
+     * Create a new request
+     * @deprecated use {@link #SimulatePipelineRequest(BytesReference, XContentType)} that does not attempt content autodetection
+     */
+    @Deprecated
     public SimulatePipelineRequest(BytesReference source) {
-        if (source == null) {
-            throw new IllegalArgumentException("source is missing");
-        }
-        this.source = source;
+        this(source, XContentFactory.xContentType(source));
+    }
+
+    /**
+     * Creates a new request with the given source and its content type
+     */
+    public SimulatePipelineRequest(BytesReference source, XContentType xContentType) {
+        this.source = Objects.requireNonNull(source);
+        this.xContentType = Objects.requireNonNull(xContentType);
     }
 
     SimulatePipelineRequest() {
@@ -78,12 +93,21 @@ public class SimulatePipelineRequest extends ActionRequest {
         return source;
     }
 
+    public XContentType getXContentType() {
+        return xContentType;
+    }
+
     @Override
     public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
         id = in.readOptionalString();
         verbose = in.readBoolean();
         source = in.readBytesReference();
+        if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType = XContentType.readFrom(in);
+        } else {
+            xContentType = XContentFactory.xContentType(source);
+        }
     }
 
     @Override
@@ -92,6 +116,9 @@ public class SimulatePipelineRequest extends ActionRequest {
         out.writeOptionalString(id);
         out.writeBoolean(verbose);
         out.writeBytesReference(source);
+        if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType.writeTo(out);
+        }
     }
 
     public static final class Fields {
diff --git a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequestBuilder.java
index 4a13fa111e..bb5d0e4e40 100644
--- a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineRequestBuilder.java
@@ -22,22 +22,46 @@ package org.elasticsearch.action.ingest;
 import org.elasticsearch.action.ActionRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 
 public class SimulatePipelineRequestBuilder extends ActionRequestBuilder<SimulatePipelineRequest, SimulatePipelineResponse, SimulatePipelineRequestBuilder> {
 
+    /**
+     * Create a new builder for {@link SimulatePipelineRequest}s
+     */
     public SimulatePipelineRequestBuilder(ElasticsearchClient client, SimulatePipelineAction action) {
         super(client, action, new SimulatePipelineRequest());
     }
 
+    /**
+     * Create a new builder for {@link SimulatePipelineRequest}s
+     * @deprecated use {@link #SimulatePipelineRequestBuilder(ElasticsearchClient, SimulatePipelineAction, BytesReference, XContentType)} to
+     *             avoid content type auto-detection on the source bytes
+     */
+    @Deprecated
     public SimulatePipelineRequestBuilder(ElasticsearchClient client, SimulatePipelineAction action, BytesReference source) {
         super(client, action, new SimulatePipelineRequest(source));
     }
 
+    /**
+     * Create a new builder for {@link SimulatePipelineRequest}s
+     */
+    public SimulatePipelineRequestBuilder(ElasticsearchClient client, SimulatePipelineAction action, BytesReference source,
+                                          XContentType xContentType) {
+        super(client, action, new SimulatePipelineRequest(source, xContentType));
+    }
+
+    /**
+     * Set the id for the pipeline to simulate
+     */
     public SimulatePipelineRequestBuilder setId(String id) {
         request.setId(id);
         return this;
     }
 
+    /**
+     * Enable or disable verbose mode
+     */
     public SimulatePipelineRequestBuilder setVerbose(boolean verbose) {
         request.setVerbose(verbose);
         return this;
diff --git a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineTransportAction.java b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineTransportAction.java
index 61fd400a1d..3f67007df6 100644
--- a/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineTransportAction.java
+++ b/core/src/main/java/org/elasticsearch/action/ingest/SimulatePipelineTransportAction.java
@@ -47,7 +47,7 @@ public class SimulatePipelineTransportAction extends HandledTransportAction<Simu
 
     @Override
     protected void doExecute(SimulatePipelineRequest request, ActionListener<SimulatePipelineResponse> listener) {
-        final Map<String, Object> source = XContentHelper.convertToMap(request.getSource(), false).v2();
+        final Map<String, Object> source = XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2();
 
         final SimulatePipelineRequest.Parsed simulateRequest;
         try {
diff --git a/core/src/main/java/org/elasticsearch/action/termvectors/TermVectorsRequest.java b/core/src/main/java/org/elasticsearch/action/termvectors/TermVectorsRequest.java
index b83713e3a6..544b14523b 100644
--- a/core/src/main/java/org/elasticsearch/action/termvectors/TermVectorsRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/termvectors/TermVectorsRequest.java
@@ -20,6 +20,7 @@
 package org.elasticsearch.action.termvectors;
 
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.RealtimeRequest;
 import org.elasticsearch.action.ValidateActions;
@@ -33,7 +34,9 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 
 import java.io.IOException;
@@ -63,6 +66,8 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
 
     private BytesReference doc;
 
+    private XContentType xContentType;
+
     private String routing;
 
     private String parent;
@@ -156,8 +161,9 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
         super(other.index());
         this.id = other.id();
         this.type = other.type();
-        if (this.doc != null) {
+        if (other.doc != null) {
             this.doc = new BytesArray(other.doc().toBytesRef(), true);
+            this.xContentType = other.xContentType;
         }
         this.flagsEnum = other.getFlags().clone();
         this.preference = other.preference();
@@ -225,22 +231,36 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
         return doc;
     }
 
+    public XContentType xContentType() {
+        return xContentType;
+    }
+
     /**
      * Sets an artificial document from which term vectors are requested for.
      */
     public TermVectorsRequest doc(XContentBuilder documentBuilder) {
-        return this.doc(documentBuilder.bytes(), true);
+        return this.doc(documentBuilder.bytes(), true, documentBuilder.contentType());
     }
 
     /**
      * Sets an artificial document from which term vectors are requested for.
+     * @deprecated use {@link #doc(BytesReference, boolean, XContentType)} to avoid content auto detection
      */
+    @Deprecated
     public TermVectorsRequest doc(BytesReference doc, boolean generateRandomId) {
+        return this.doc(doc, generateRandomId, XContentFactory.xContentType(doc));
+    }
+
+    /**
+     * Sets an artificial document from which term vectors are requested for.
+     */
+    public TermVectorsRequest doc(BytesReference doc, boolean generateRandomId, XContentType xContentType) {
         // assign a random id to this artificial document, for routing
         if (generateRandomId) {
             this.id(String.valueOf(randomInt.getAndAdd(1)));
         }
         this.doc = doc;
+        this.xContentType = xContentType;
         return this;
     }
 
@@ -479,6 +499,11 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
 
         if (in.readBoolean()) {
             doc = in.readBytesReference();
+            if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+                xContentType = XContentType.readFrom(in);
+            } else {
+                xContentType = XContentFactory.xContentType(doc);
+            }
         }
         routing = in.readOptionalString();
         parent = in.readOptionalString();
@@ -519,6 +544,9 @@ public class TermVectorsRequest extends SingleShardRequest<TermVectorsRequest> i
         out.writeBoolean(doc != null);
         if (doc != null) {
             out.writeBytesReference(doc);
+            if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+                xContentType.writeTo(out);
+            }
         }
         out.writeOptionalString(routing);
         out.writeOptionalString(parent);
diff --git a/core/src/main/java/org/elasticsearch/action/update/TransportUpdateAction.java b/core/src/main/java/org/elasticsearch/action/update/TransportUpdateAction.java
index 45e4aa8afd..4e2a7b466b 100644
--- a/core/src/main/java/org/elasticsearch/action/update/TransportUpdateAction.java
+++ b/core/src/main/java/org/elasticsearch/action/update/TransportUpdateAction.java
@@ -186,7 +186,8 @@ public class TransportUpdateAction extends TransportInstanceSingleOperationActio
                         UpdateResponse update = new UpdateResponse(response.getShardInfo(), response.getShardId(), response.getType(), response.getId(), response.getSeqNo(), response.getVersion(), response.getResult());
                         if ((request.fetchSource() != null && request.fetchSource().fetchSource()) ||
                             (request.fields() != null && request.fields().length > 0)) {
-                            Tuple<XContentType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(upsertSourceBytes, true);
+                            Tuple<XContentType, Map<String, Object>> sourceAndContent =
+                                XContentHelper.convertToMap(upsertSourceBytes, true, upsertRequest.getContentType());
                             update.setGetResult(updateHelper.extractGetResult(request, request.concreteIndex(), response.getVersion(), sourceAndContent.v2(), sourceAndContent.v1(), upsertSourceBytes));
                         } else {
                             update.setGetResult(null);
diff --git a/core/src/main/java/org/elasticsearch/action/update/UpdateRequest.java b/core/src/main/java/org/elasticsearch/action/update/UpdateRequest.java
index 0d2801e44a..504a297627 100644
--- a/core/src/main/java/org/elasticsearch/action/update/UpdateRequest.java
+++ b/core/src/main/java/org/elasticsearch/action/update/UpdateRequest.java
@@ -29,8 +29,6 @@ import org.elasticsearch.action.support.single.instance.InstanceShardOperationRe
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.logging.DeprecationLogger;
-import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -52,8 +50,6 @@ import static org.elasticsearch.action.ValidateActions.addValidationError;
 
 public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
         implements DocWriteRequest<UpdateRequest>, WriteRequest<UpdateRequest> {
-    private static final DeprecationLogger DEPRECATION_LOGGER =
-        new DeprecationLogger(Loggers.getLogger(UpdateRequest.class));
 
     private String type;
     private String id;
@@ -559,7 +555,9 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
 
     /**
      * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #doc(String, XContentType)}
      */
+    @Deprecated
     public UpdateRequest doc(String source) {
         safeDoc().source(source);
         return this;
@@ -568,6 +566,16 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
+    public UpdateRequest doc(String source, XContentType xContentType) {
+        safeDoc().source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #doc(byte[], XContentType)}
+     */
+    @Deprecated
     public UpdateRequest doc(byte[] source) {
         safeDoc().source(source);
         return this;
@@ -576,12 +584,30 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
+    public UpdateRequest doc(byte[] source, XContentType xContentType) {
+        safeDoc().source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #doc(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public UpdateRequest doc(byte[] source, int offset, int length) {
         safeDoc().source(source, offset, length);
         return this;
     }
 
     /**
+     * Sets the doc to use for updates when a script is not specified.
+     */
+    public UpdateRequest doc(byte[] source, int offset, int length, XContentType xContentType) {
+        safeDoc().source(source, offset, length, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the doc to use for updates when a script is not specified, the doc provided
      * is a field and value pairs.
      */
@@ -591,10 +617,11 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     }
 
     /**
-     * Sets the doc to use for updates when a script is not specified.
+     * Sets the doc to use for updates when a script is not specified, the doc provided
+     * is a field and value pairs.
      */
-    public UpdateRequest doc(String field, Object value) {
-        safeDoc().source(field, value);
+    public UpdateRequest doc(XContentType xContentType, Object... source) {
+        safeDoc().source(xContentType, source);
         return this;
     }
 
@@ -644,7 +671,9 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #upsert(String, XContentType)}
      */
+    @Deprecated
     public UpdateRequest upsert(String source) {
         safeUpsertRequest().source(source);
         return this;
@@ -653,6 +682,16 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
+    public UpdateRequest upsert(String source, XContentType xContentType) {
+        safeUpsertRequest().source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #upsert(byte[], XContentType)}
+     */
+    @Deprecated
     public UpdateRequest upsert(byte[] source) {
         safeUpsertRequest().source(source);
         return this;
@@ -661,12 +700,30 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
+    public UpdateRequest upsert(byte[] source, XContentType xContentType) {
+        safeUpsertRequest().source(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #upsert(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public UpdateRequest upsert(byte[] source, int offset, int length) {
         safeUpsertRequest().source(source, offset, length);
         return this;
     }
 
     /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     */
+    public UpdateRequest upsert(byte[] source, int offset, int length, XContentType xContentType) {
+        safeUpsertRequest().source(source, offset, length, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the doc source of the update request to be used when the document does not exists. The doc
      * includes field and value pairs.
      */
@@ -675,6 +732,15 @@ public class UpdateRequest extends InstanceShardOperationRequest<UpdateRequest>
         return this;
     }
 
+    /**
+     * Sets the doc source of the update request to be used when the document does not exists. The doc
+     * includes field and value pairs.
+     */
+    public UpdateRequest upsert(XContentType xContentType, Object... source) {
+        safeUpsertRequest().source(xContentType, source);
+        return this;
+    }
+
     public IndexRequest upsertRequest() {
         return this.upsertRequest;
     }
diff --git a/core/src/main/java/org/elasticsearch/action/update/UpdateRequestBuilder.java b/core/src/main/java/org/elasticsearch/action/update/UpdateRequestBuilder.java
index 50d84a2412..1a4d4077b1 100644
--- a/core/src/main/java/org/elasticsearch/action/update/UpdateRequestBuilder.java
+++ b/core/src/main/java/org/elasticsearch/action/update/UpdateRequestBuilder.java
@@ -223,7 +223,9 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
 
     /**
      * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #setDoc(String, XContentType)}
      */
+    @Deprecated
     public UpdateRequestBuilder setDoc(String source) {
         request.doc(source);
         return this;
@@ -232,6 +234,16 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
+    public UpdateRequestBuilder setDoc(String source, XContentType xContentType) {
+        request.doc(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #setDoc(byte[], XContentType)}
+     */
+    @Deprecated
     public UpdateRequestBuilder setDoc(byte[] source) {
         request.doc(source);
         return this;
@@ -240,6 +252,16 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
+    public UpdateRequestBuilder setDoc(byte[] source, XContentType xContentType) {
+        request.doc(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc to use for updates when a script is not specified.
+     * @deprecated use {@link #setDoc(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public UpdateRequestBuilder setDoc(byte[] source, int offset, int length) {
         request.doc(source, offset, length);
         return this;
@@ -248,8 +270,8 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     /**
      * Sets the doc to use for updates when a script is not specified.
      */
-    public UpdateRequestBuilder setDoc(String field, Object value) {
-        request.doc(field, value);
+    public UpdateRequestBuilder setDoc(byte[] source, int offset, int length, XContentType xContentType) {
+        request.doc(source, offset, length, xContentType);
         return this;
     }
 
@@ -263,6 +285,15 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     }
 
     /**
+     * Sets the doc to use for updates when a script is not specified, the doc provided
+     * is a field and value pairs.
+     */
+    public UpdateRequestBuilder setDoc(XContentType xContentType, Object... source) {
+        request.doc(xContentType, source);
+        return this;
+    }
+
+    /**
      * Sets the index request to be used if the document does not exists. Otherwise, a {@link org.elasticsearch.index.engine.DocumentMissingException}
      * is thrown.
      */
@@ -297,7 +328,9 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
 
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #setUpsert(String, XContentType)}
      */
+    @Deprecated
     public UpdateRequestBuilder setUpsert(String source) {
         request.upsert(source);
         return this;
@@ -306,6 +339,16 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
+    public UpdateRequestBuilder setUpsert(String source, XContentType xContentType) {
+        request.upsert(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #setDoc(byte[], XContentType)}
+     */
+    @Deprecated
     public UpdateRequestBuilder setUpsert(byte[] source) {
         request.upsert(source);
         return this;
@@ -314,12 +357,30 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     /**
      * Sets the doc source of the update request to be used when the document does not exists.
      */
+    public UpdateRequestBuilder setUpsert(byte[] source, XContentType xContentType) {
+        request.upsert(source, xContentType);
+        return this;
+    }
+
+    /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     * @deprecated use {@link #setUpsert(byte[], int, int, XContentType)}
+     */
+    @Deprecated
     public UpdateRequestBuilder setUpsert(byte[] source, int offset, int length) {
         request.upsert(source, offset, length);
         return this;
     }
 
     /**
+     * Sets the doc source of the update request to be used when the document does not exists.
+     */
+    public UpdateRequestBuilder setUpsert(byte[] source, int offset, int length, XContentType xContentType) {
+        request.upsert(source, offset, length, xContentType);
+        return this;
+    }
+
+    /**
      * Sets the doc source of the update request to be used when the document does not exists. The doc
      * includes field and value pairs.
      */
@@ -329,6 +390,15 @@ public class UpdateRequestBuilder extends InstanceShardOperationRequestBuilder<U
     }
 
     /**
+     * Sets the doc source of the update request to be used when the document does not exists. The doc
+     * includes field and value pairs.
+     */
+    public UpdateRequestBuilder setUpsert(XContentType xContentType, Object... source) {
+        request.upsert(xContentType, source);
+        return this;
+    }
+
+    /**
      * Sets whether the specified doc parameter should be used as upsert document.
      */
     public UpdateRequestBuilder setDocAsUpsert(boolean shouldUpsertDoc) {
diff --git a/core/src/main/java/org/elasticsearch/client/ClusterAdminClient.java b/core/src/main/java/org/elasticsearch/client/ClusterAdminClient.java
index 14abc77513..3f705a215e 100644
--- a/core/src/main/java/org/elasticsearch/client/ClusterAdminClient.java
+++ b/core/src/main/java/org/elasticsearch/client/ClusterAdminClient.java
@@ -112,6 +112,7 @@ import org.elasticsearch.action.ingest.SimulatePipelineResponse;
 import org.elasticsearch.action.ingest.WritePipelineResponse;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.tasks.TaskId;
 
 /**
@@ -545,10 +546,17 @@ public interface ClusterAdminClient extends ElasticsearchClient {
 
     /**
      * Stores an ingest pipeline
+     * @deprecated use {@link #preparePutPipeline(String, BytesReference, XContentType)}
      */
+    @Deprecated
     PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source);
 
     /**
+     * Stores an ingest pipeline
+     */
+    PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, XContentType xContentType);
+
+    /**
      * Deletes a stored ingest pipeline
      */
     void deletePipeline(DeletePipelineRequest request, ActionListener<WritePipelineResponse> listener);
@@ -596,9 +604,15 @@ public interface ClusterAdminClient extends ElasticsearchClient {
     /**
      * Simulates an ingest pipeline
      */
+    @Deprecated
     SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source);
 
     /**
+     * Simulates an ingest pipeline
+     */
+    SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, XContentType xContentType);
+
+    /**
      * Explain the allocation of a shard
      */
     void allocationExplain(ClusterAllocationExplainRequest request, ActionListener<ClusterAllocationExplainResponse> listener);
diff --git a/core/src/main/java/org/elasticsearch/client/support/AbstractClient.java b/core/src/main/java/org/elasticsearch/client/support/AbstractClient.java
index b93c00ca9f..5a789af3ee 100644
--- a/core/src/main/java/org/elasticsearch/client/support/AbstractClient.java
+++ b/core/src/main/java/org/elasticsearch/client/support/AbstractClient.java
@@ -343,6 +343,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.tasks.TaskId;
 import org.elasticsearch.threadpool.ThreadPool;
 
@@ -1082,6 +1083,11 @@ public abstract class AbstractClient extends AbstractComponent implements Client
         }
 
         @Override
+        public PutPipelineRequestBuilder preparePutPipeline(String id, BytesReference source, XContentType xContentType) {
+            return new PutPipelineRequestBuilder(this, PutPipelineAction.INSTANCE, id, source, xContentType);
+        }
+
+        @Override
         public void deletePipeline(DeletePipelineRequest request, ActionListener<WritePipelineResponse> listener) {
             execute(DeletePipelineAction.INSTANCE, request, listener);
         }
@@ -1132,6 +1138,11 @@ public abstract class AbstractClient extends AbstractComponent implements Client
         }
 
         @Override
+        public SimulatePipelineRequestBuilder prepareSimulatePipeline(BytesReference source, XContentType xContentType) {
+            return new SimulatePipelineRequestBuilder(this, SimulatePipelineAction.INSTANCE, source, xContentType);
+        }
+
+        @Override
         public void allocationExplain(ClusterAllocationExplainRequest request, ActionListener<ClusterAllocationExplainResponse> listener) {
             execute(ClusterAllocationExplainAction.INSTANCE, request, listener);
         }
diff --git a/core/src/main/java/org/elasticsearch/cluster/metadata/IndexTemplateMetaData.java b/core/src/main/java/org/elasticsearch/cluster/metadata/IndexTemplateMetaData.java
index 4ba244e107..5bba34904d 100644
--- a/core/src/main/java/org/elasticsearch/cluster/metadata/IndexTemplateMetaData.java
+++ b/core/src/main/java/org/elasticsearch/cluster/metadata/IndexTemplateMetaData.java
@@ -26,6 +26,7 @@ import org.elasticsearch.cluster.AbstractDiffable;
 import org.elasticsearch.cluster.Diff;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.compress.CompressedXContent;
diff --git a/core/src/main/java/org/elasticsearch/cluster/metadata/MetaDataCreateIndexService.java b/core/src/main/java/org/elasticsearch/cluster/metadata/MetaDataCreateIndexService.java
index 0efb640c5a..0bde4a23b0 100644
--- a/core/src/main/java/org/elasticsearch/cluster/metadata/MetaDataCreateIndexService.java
+++ b/core/src/main/java/org/elasticsearch/cluster/metadata/MetaDataCreateIndexService.java
@@ -265,11 +265,13 @@ public class MetaDataCreateIndexService extends AbstractComponent {
                             for (IndexTemplateMetaData template : templates) {
                                 templateNames.add(template.getName());
                                 for (ObjectObjectCursor<String, CompressedXContent> cursor : template.mappings()) {
+                                    String mappingString = cursor.value.string();
                                     if (mappings.containsKey(cursor.key)) {
                                         XContentHelper.mergeDefaults(mappings.get(cursor.key),
-                                                MapperService.parseMapping(xContentRegistry, cursor.value.string()));
+                                                MapperService.parseMapping(xContentRegistry, mappingString));
                                     } else {
-                                        mappings.put(cursor.key, MapperService.parseMapping(xContentRegistry, cursor.value.string()));
+                                        mappings.put(cursor.key,
+                                            MapperService.parseMapping(xContentRegistry, mappingString));
                                     }
                                 }
                                 // handle custom
diff --git a/core/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java b/core/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java
index 279be58e01..69adc5878f 100644
--- a/core/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java
+++ b/core/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java
@@ -237,6 +237,7 @@ public final class ClusterSettings extends AbstractScopedSettings {
                     HttpTransportSettings.SETTING_CORS_ALLOW_METHODS,
                     HttpTransportSettings.SETTING_CORS_ALLOW_HEADERS,
                     HttpTransportSettings.SETTING_HTTP_DETAILED_ERRORS_ENABLED,
+                    HttpTransportSettings.SETTING_HTTP_CONTENT_TYPE_REQUIRED,
                     HttpTransportSettings.SETTING_HTTP_MAX_CONTENT_LENGTH,
                     HttpTransportSettings.SETTING_HTTP_MAX_CHUNK_SIZE,
                     HttpTransportSettings.SETTING_HTTP_MAX_HEADER_SIZE,
diff --git a/core/src/main/java/org/elasticsearch/common/settings/Settings.java b/core/src/main/java/org/elasticsearch/common/settings/Settings.java
index 883f1e7c82..579be7ce31 100644
--- a/core/src/main/java/org/elasticsearch/common/settings/Settings.java
+++ b/core/src/main/java/org/elasticsearch/common/settings/Settings.java
@@ -37,6 +37,7 @@ import org.elasticsearch.common.unit.SizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -960,7 +961,9 @@ public final class Settings implements ToXContent {
         /**
          * Loads settings from the actual string content that represents them using the
          * {@link SettingsLoaderFactory#loaderFromSource(String)}.
+         * @deprecated use {@link #loadFromSource(String, XContentType)} to avoid content type detection
          */
+        @Deprecated
         public Builder loadFromSource(String source) {
             SettingsLoader settingsLoader = SettingsLoaderFactory.loaderFromSource(source);
             try {
@@ -973,8 +976,23 @@ public final class Settings implements ToXContent {
         }
 
         /**
+         * Loads settings from the actual string content that represents them using the
+         * {@link SettingsLoaderFactory#loaderFromXContentType(XContentType)} method to obtain a loader
+         */
+        public Builder loadFromSource(String source, XContentType xContentType) {
+            SettingsLoader settingsLoader = SettingsLoaderFactory.loaderFromXContentType(xContentType);
+            try {
+                Map<String, String> loadedSettings = settingsLoader.load(source);
+                put(loadedSettings);
+            } catch (Exception e) {
+                throw new SettingsException("Failed to load settings from [" + source + "]", e);
+            }
+            return this;
+        }
+
+        /**
          * Loads settings from a url that represents them using the
-         * {@link SettingsLoaderFactory#loaderFromSource(String)}.
+         * {@link SettingsLoaderFactory#loaderFromResource(String)}.
          */
         public Builder loadFromPath(Path path) throws IOException {
             // NOTE: loadFromStream will close the input stream
@@ -983,7 +1001,7 @@ public final class Settings implements ToXContent {
 
         /**
          * Loads settings from a stream that represents them using the
-         * {@link SettingsLoaderFactory#loaderFromSource(String)}.
+         * {@link SettingsLoaderFactory#loaderFromResource(String)}.
          */
         public Builder loadFromStream(String resourceName, InputStream is) throws IOException {
             SettingsLoader settingsLoader = SettingsLoaderFactory.loaderFromResource(resourceName);
diff --git a/core/src/main/java/org/elasticsearch/common/settings/loader/SettingsLoaderFactory.java b/core/src/main/java/org/elasticsearch/common/settings/loader/SettingsLoaderFactory.java
index 5f2da22c5f..5d8cb4918b 100644
--- a/core/src/main/java/org/elasticsearch/common/settings/loader/SettingsLoaderFactory.java
+++ b/core/src/main/java/org/elasticsearch/common/settings/loader/SettingsLoaderFactory.java
@@ -19,6 +19,8 @@
 
 package org.elasticsearch.common.settings.loader;
 
+import org.elasticsearch.common.xcontent.XContentType;
+
 /**
  * A class holding factory methods for settings loaders that attempts
  * to infer the type of the underlying settings content.
@@ -33,9 +35,7 @@ public final class SettingsLoaderFactory {
      * name. This factory method assumes that if the resource name ends
      * with ".json" then the content should be parsed as JSON, else if
      * the resource name ends with ".yml" or ".yaml" then the content
-     * should be parsed as YAML, else if the resource name ends with
-     * ".properties" then the content should be parsed as properties,
-     * otherwise default to attempting to parse as JSON. Note that the
+     * should be parsed as YAML, otherwise throws an exception. Note that the
      * parsers returned by this method will not accept null-valued
      * keys.
      *
@@ -59,13 +59,15 @@ public final class SettingsLoaderFactory {
      * contains an opening and closing brace ('{' and '}') then the
      * content should be parsed as JSON, else if the underlying content
      * fails this condition but contains a ':' then the content should
-     * be parsed as YAML, and otherwise should be parsed as properties.
+     * be parsed as YAML, and otherwise throws an exception.
      * Note that the JSON and YAML parsers returned by this method will
      * accept null-valued keys.
      *
      * @param source The underlying settings content.
      * @return A settings loader.
+     * @deprecated use {@link #loaderFromXContentType(XContentType)} instead
      */
+    @Deprecated
     public static SettingsLoader loaderFromSource(String source) {
         if (source.indexOf('{') != -1 && source.indexOf('}') != -1) {
             return new JsonSettingsLoader(true);
@@ -76,4 +78,20 @@ public final class SettingsLoaderFactory {
         }
     }
 
+    /**
+     * Returns a {@link SettingsLoader} based on the {@link XContentType}. Note only {@link XContentType#JSON} and
+     * {@link XContentType#YAML} are supported
+     *
+     * @param xContentType The content type
+     * @return A settings loader.
+     */
+    public static SettingsLoader loaderFromXContentType(XContentType xContentType) {
+        if (xContentType == XContentType.JSON) {
+            return new JsonSettingsLoader(true);
+        } else if (xContentType == XContentType.YAML) {
+            return new YamlSettingsLoader(true);
+        } else {
+            throw new IllegalArgumentException("unsupported content type [" + xContentType + "]");
+        }
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/XContentBuilder.java b/core/src/main/java/org/elasticsearch/common/xcontent/XContentBuilder.java
index df34ec726f..189e9d3c8d 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/XContentBuilder.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/XContentBuilder.java
@@ -964,21 +964,60 @@ public final class XContentBuilder implements BytesStream, Releasable, Flushable
     // Raw fields
     //////////////////////////////////
 
+    /**
+     * Writes a raw field with the value taken from the bytes in the stream
+     * @deprecated use {@link #rawField(String, InputStream, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     public XContentBuilder rawField(String name, InputStream value) throws IOException {
         generator.writeRawField(name, value);
         return this;
     }
 
+    /**
+     * Writes a raw field with the value taken from the bytes in the stream
+     */
+    public XContentBuilder rawField(String name, InputStream value, XContentType contentType) throws IOException {
+        generator.writeRawField(name, value, contentType);
+        return this;
+    }
+
+    /**
+     * Writes a raw field with the given bytes as the value
+     * @deprecated use {@link #rawField(String name, BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     public XContentBuilder rawField(String name, BytesReference value) throws IOException {
         generator.writeRawField(name, value);
         return this;
     }
 
+    /**
+     * Writes a raw field with the given bytes as the value
+     */
+    public XContentBuilder rawField(String name, BytesReference value, XContentType contentType) throws IOException {
+        generator.writeRawField(name, value, contentType);
+        return this;
+    }
+
+    /**
+     * Writes a value with the source coming directly from the bytes
+     * @deprecated use {@link #rawValue(BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     public XContentBuilder rawValue(BytesReference value) throws IOException {
         generator.writeRawValue(value);
         return this;
     }
 
+    /**
+     * Writes a value with the source coming directly from the bytes
+     */
+    public XContentBuilder rawValue(BytesReference value, XContentType contentType) throws IOException {
+        generator.writeRawValue(value, contentType);
+        return this;
+    }
+
     public XContentBuilder copyCurrentStructure(XContentParser parser) throws IOException {
         generator.copyCurrentStructure(parser);
         return this;
diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/XContentGenerator.java b/core/src/main/java/org/elasticsearch/common/xcontent/XContentGenerator.java
index 478f3a8a08..60a188ca6c 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/XContentGenerator.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/XContentGenerator.java
@@ -86,12 +86,42 @@ public interface XContentGenerator extends Closeable, Flushable {
 
     void writeBinary(byte[] value, int offset, int length) throws IOException;
 
+    /**
+     * Writes a raw field with the value taken from the bytes in the stream
+     * @deprecated use {@link #writeRawField(String, InputStream, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     void writeRawField(String name, InputStream value) throws IOException;
 
+    /**
+     * Writes a raw field with the value taken from the bytes in the stream
+     */
+    void writeRawField(String name, InputStream value, XContentType xContentType) throws IOException;
+
+    /**
+     * Writes a raw field with the given bytes as the value
+     * @deprecated use {@link #writeRawField(String, BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     void writeRawField(String name, BytesReference value) throws IOException;
 
+    /**
+     * Writes a raw field with the given bytes as the value
+     */
+    void writeRawField(String name, BytesReference value, XContentType xContentType) throws IOException;
+
+    /**
+     * Writes a value with the source coming directly from the bytes
+     * @deprecated use {@link #writeRawValue(BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     void writeRawValue(BytesReference value) throws IOException;
 
+    /**
+     * Writes a value with the source coming directly from the bytes
+     */
+    void writeRawValue(BytesReference value, XContentType xContentType) throws IOException;
+
     void copyCurrentStructure(XContentParser parser) throws IOException;
 
     /**
diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/XContentHelper.java b/core/src/main/java/org/elasticsearch/common/xcontent/XContentHelper.java
index 6cf8d12c21..dd7508280d 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/XContentHelper.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/XContentHelper.java
@@ -41,6 +41,11 @@ import static org.elasticsearch.common.xcontent.ToXContent.EMPTY_PARAMS;
 @SuppressWarnings("unchecked")
 public class XContentHelper {
 
+    /**
+     * Creates a parser based on the bytes provided
+     * @deprecated use {@link #createParser(NamedXContentRegistry, BytesReference, XContentType)} to avoid content type auto-detection
+     */
+    @Deprecated
     public static XContentParser createParser(NamedXContentRegistry xContentRegistry, BytesReference bytes) throws IOException {
         Compressor compressor = CompressorFactory.compressor(bytes);
         if (compressor != null) {
@@ -48,17 +53,49 @@ public class XContentHelper {
             if (compressedInput.markSupported() == false) {
                 compressedInput = new BufferedInputStream(compressedInput);
             }
-            XContentType contentType = XContentFactory.xContentType(compressedInput);
+            final XContentType contentType = XContentFactory.xContentType(compressedInput);
             return XContentFactory.xContent(contentType).createParser(xContentRegistry, compressedInput);
         } else {
             return XContentFactory.xContent(bytes).createParser(xContentRegistry, bytes.streamInput());
         }
     }
 
+    /**
+     * Creates a parser for the bytes using the supplied content-type
+     */
+    public static XContentParser createParser(NamedXContentRegistry xContentRegistry, BytesReference bytes,
+                                              XContentType xContentType) throws IOException {
+        Objects.requireNonNull(xContentType);
+        Compressor compressor = CompressorFactory.compressor(bytes);
+        if (compressor != null) {
+            InputStream compressedInput = compressor.streamInput(bytes.streamInput());
+            if (compressedInput.markSupported() == false) {
+                compressedInput = new BufferedInputStream(compressedInput);
+            }
+            return XContentFactory.xContent(xContentType).createParser(xContentRegistry, compressedInput);
+        } else {
+            return xContentType.xContent().createParser(xContentRegistry, bytes.streamInput());
+        }
+    }
+
+    /**
+     * Converts the given bytes into a map that is optionally ordered.
+     * @deprecated this method relies on auto-detection of content type. Use {@link #convertToMap(BytesReference, boolean, XContentType)}
+     *             instead with the proper {@link XContentType}
+     */
+    @Deprecated
     public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReference bytes, boolean ordered)
             throws ElasticsearchParseException {
+        return convertToMap(bytes, ordered, null);
+    }
+
+    /**
+     * Converts the given bytes into a map that is optionally ordered. The provided {@link XContentType} must be non-null.
+     */
+    public static Tuple<XContentType, Map<String, Object>> convertToMap(BytesReference bytes, boolean ordered, XContentType xContentType)
+        throws ElasticsearchParseException {
         try {
-            XContentType contentType;
+            final XContentType contentType;
             InputStream input;
             Compressor compressor = CompressorFactory.compressor(bytes);
             if (compressor != null) {
@@ -66,13 +103,12 @@ public class XContentHelper {
                 if (compressedStreamInput.markSupported() == false) {
                     compressedStreamInput = new BufferedInputStream(compressedStreamInput);
                 }
-                contentType = XContentFactory.xContentType(compressedStreamInput);
                 input = compressedStreamInput;
             } else {
-                contentType = XContentFactory.xContentType(bytes);
                 input = bytes.streamInput();
             }
-            return new Tuple<>(contentType, convertToMap(XContentFactory.xContent(contentType), input, ordered));
+            contentType = xContentType != null ? xContentType : XContentFactory.xContentType(input);
+            return new Tuple<>(Objects.requireNonNull(contentType), convertToMap(XContentFactory.xContent(contentType), input, ordered));
         } catch (IOException e) {
             throw new ElasticsearchParseException("Failed to parse content to map", e);
         }
@@ -105,15 +141,27 @@ public class XContentHelper {
         }
     }
 
+    @Deprecated
     public static String convertToJson(BytesReference bytes, boolean reformatJson) throws IOException {
         return convertToJson(bytes, reformatJson, false);
     }
 
+    @Deprecated
     public static String convertToJson(BytesReference bytes, boolean reformatJson, boolean prettyPrint) throws IOException {
-        XContentType xContentType = XContentFactory.xContentType(bytes);
+        return convertToJson(bytes, reformatJson, prettyPrint, XContentFactory.xContentType(bytes));
+    }
+
+    public static String convertToJson(BytesReference bytes, boolean reformatJson, XContentType xContentType) throws IOException {
+        return convertToJson(bytes, reformatJson, false, xContentType);
+    }
+
+    public static String convertToJson(BytesReference bytes, boolean reformatJson, boolean prettyPrint, XContentType xContentType)
+        throws IOException {
+        Objects.requireNonNull(xContentType);
         if (xContentType == XContentType.JSON && !reformatJson) {
             return bytes.utf8ToString();
         }
+
         // It is safe to use EMPTY here because this never uses namedObject
         try (XContentParser parser = XContentFactory.xContent(xContentType).createParser(NamedXContentRegistry.EMPTY,
                 bytes.streamInput())) {
@@ -365,7 +413,10 @@ public class XContentHelper {
     /**
      * Writes a "raw" (bytes) field, handling cases where the bytes are compressed, and tries to optimize writing using
      * {@link XContentBuilder#rawField(String, org.elasticsearch.common.bytes.BytesReference)}.
+     * @deprecated use {@link #writeRawField(String, BytesReference, XContentType, XContentBuilder, Params)} to avoid content type
+     * auto-detection
      */
+    @Deprecated
     public static void writeRawField(String field, BytesReference source, XContentBuilder builder, ToXContent.Params params) throws IOException {
         Compressor compressor = CompressorFactory.compressor(source);
         if (compressor != null) {
@@ -377,6 +428,22 @@ public class XContentHelper {
     }
 
     /**
+     * Writes a "raw" (bytes) field, handling cases where the bytes are compressed, and tries to optimize writing using
+     * {@link XContentBuilder#rawField(String, org.elasticsearch.common.bytes.BytesReference, XContentType)}.
+     */
+    public static void writeRawField(String field, BytesReference source, XContentType xContentType, XContentBuilder builder,
+                                     ToXContent.Params params) throws IOException {
+        Objects.requireNonNull(xContentType);
+        Compressor compressor = CompressorFactory.compressor(source);
+        if (compressor != null) {
+            InputStream compressedStreamInput = compressor.streamInput(source.streamInput());
+            builder.rawField(field, compressedStreamInput, xContentType);
+        } else {
+            builder.rawField(field, source, xContentType);
+        }
+    }
+
+    /**
      * Returns the bytes that represent the XContent output of the provided {@link ToXContent} object, using the provided
      * {@link XContentType}. Wraps the output into a new anonymous object.
      */
diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java b/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
index ddd736e0d0..8e3c298270 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/XContentType.java
@@ -29,6 +29,7 @@ import org.elasticsearch.common.xcontent.yaml.YamlXContent;
 
 import java.io.IOException;
 import java.util.Locale;
+import java.util.Objects;
 
 /**
  * The content type of {@link org.elasticsearch.common.xcontent.XContent}.
@@ -40,7 +41,7 @@ public enum XContentType implements Writeable {
      */
     JSON(0) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/json";
         }
 
@@ -64,7 +65,7 @@ public enum XContentType implements Writeable {
      */
     SMILE(1) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/smile";
         }
 
@@ -83,7 +84,7 @@ public enum XContentType implements Writeable {
      */
     YAML(2) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/yaml";
         }
 
@@ -102,7 +103,7 @@ public enum XContentType implements Writeable {
      */
     CBOR(3) {
         @Override
-        protected String mediaTypeWithoutParameters() {
+        public String mediaTypeWithoutParameters() {
             return "application/cbor";
         }
 
@@ -117,12 +118,18 @@ public enum XContentType implements Writeable {
         }
     };
 
+    /**
+     * Accepts either a format string, which is equivalent to {@link XContentType#shortName()} or a media type that optionally has
+     * parameters and attempts to match the value to an {@link XContentType}. The comparisons are done in lower case format and this method
+     * also supports a wildcard accept for {@code application/*}. This method can be used to parse the {@code Accept} HTTP header or a
+     * format query string parameter. This method will return {@code null} if no match is found
+     */
     public static XContentType fromMediaTypeOrFormat(String mediaType) {
         if (mediaType == null) {
             return null;
         }
         for (XContentType type : values()) {
-            if (isSameMediaTypeAs(mediaType, type)) {
+            if (isSameMediaTypeOrFormatAs(mediaType, type)) {
                 return type;
             }
         }
@@ -133,7 +140,22 @@ public enum XContentType implements Writeable {
         return null;
     }
 
-    private static boolean isSameMediaTypeAs(String stringType, XContentType type) {
+    /**
+     * Attempts to match the given media type with the known {@link XContentType} values. This match is done in a case-insensitive manner.
+     * The provided media type should not include any parameters. This method is suitable for parsing part of the {@code Content-Type}
+     * HTTP header. This method will return {@code null} if no match is found
+     */
+    public static XContentType fromMediaType(String mediaType) {
+        final String lowercaseMediaType = Objects.requireNonNull(mediaType, "mediaType cannot be null").toLowerCase(Locale.ROOT);
+        for (XContentType type : values()) {
+            if (type.mediaTypeWithoutParameters().equals(lowercaseMediaType)) {
+                return type;
+            }
+        }
+        return null;
+    }
+
+    private static boolean isSameMediaTypeOrFormatAs(String stringType, XContentType type) {
         return type.mediaTypeWithoutParameters().equalsIgnoreCase(stringType) ||
                 stringType.toLowerCase(Locale.ROOT).startsWith(type.mediaTypeWithoutParameters().toLowerCase(Locale.ROOT) + ";") ||
                 type.shortName().equalsIgnoreCase(stringType);
@@ -157,7 +179,7 @@ public enum XContentType implements Writeable {
 
     public abstract XContent xContent();
 
-    protected abstract String mediaTypeWithoutParameters();
+    public abstract String mediaTypeWithoutParameters();
 
     public static XContentType readFrom(StreamInput in) throws IOException {
         int index = in.readVInt();
diff --git a/core/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java b/core/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
index 07ae16b96c..1e09f8334f 100644
--- a/core/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
+++ b/core/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
@@ -307,6 +307,11 @@ public class JsonXContentGenerator implements XContentGenerator {
         if (contentType == null) {
             throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
         }
+        writeRawField(name, content, contentType);
+    }
+
+    @Override
+    public void writeRawField(String name, InputStream content, XContentType contentType) throws IOException {
         if (mayWriteRawData(contentType) == false) {
             // EMPTY is safe here because we never call namedObject when writing raw data
             try (XContentParser parser = XContentFactory.xContent(contentType).createParser(NamedXContentRegistry.EMPTY, content)) {
@@ -328,6 +333,11 @@ public class JsonXContentGenerator implements XContentGenerator {
         if (contentType == null) {
             throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
         }
+        writeRawField(name, content, contentType);
+    }
+
+    @Override
+    public final void writeRawField(String name, BytesReference content, XContentType contentType) throws IOException {
         if (mayWriteRawData(contentType) == false) {
             writeFieldName(name);
             copyRawValue(content, contentType.xContent());
@@ -345,6 +355,11 @@ public class JsonXContentGenerator implements XContentGenerator {
         if (contentType == null) {
             throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
         }
+        writeRawValue(content, contentType);
+    }
+
+    @Override
+    public final void writeRawValue(BytesReference content, XContentType contentType) throws IOException {
         if (mayWriteRawData(contentType) == false) {
             copyRawValue(content, contentType.xContent());
         } else {
diff --git a/core/src/main/java/org/elasticsearch/http/HttpTransportSettings.java b/core/src/main/java/org/elasticsearch/http/HttpTransportSettings.java
index 60bc3449d0..b5e254aa4c 100644
--- a/core/src/main/java/org/elasticsearch/http/HttpTransportSettings.java
+++ b/core/src/main/java/org/elasticsearch/http/HttpTransportSettings.java
@@ -68,6 +68,8 @@ public final class HttpTransportSettings {
         Setting.intSetting("http.publish_port", -1, -1, Property.NodeScope);
     public static final Setting<Boolean> SETTING_HTTP_DETAILED_ERRORS_ENABLED =
         Setting.boolSetting("http.detailed_errors.enabled", true, Property.NodeScope);
+    public static final Setting<Boolean> SETTING_HTTP_CONTENT_TYPE_REQUIRED =
+        Setting.boolSetting("http.content_type.required", false, Property.NodeScope);
     public static final Setting<ByteSizeValue> SETTING_HTTP_MAX_CONTENT_LENGTH =
         Setting.byteSizeSetting("http.max_content_length", new ByteSizeValue(100, ByteSizeUnit.MB), Property.NodeScope);
     public static final Setting<ByteSizeValue> SETTING_HTTP_MAX_CHUNK_SIZE =
diff --git a/core/src/main/java/org/elasticsearch/index/IndexingSlowLog.java b/core/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
index 8672bbc835..b1d8ac1886 100644
--- a/core/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
+++ b/core/src/main/java/org/elasticsearch/index/IndexingSlowLog.java
@@ -190,7 +190,7 @@ public final class IndexingSlowLog implements IndexingOperationListener {
                 return sb.toString();
             }
             try {
-                String source = XContentHelper.convertToJson(doc.source(), reformat);
+                String source = XContentHelper.convertToJson(doc.source(), reformat, doc.getXContentType());
                 sb.append(", source[").append(Strings.cleanTruncate(source, maxSourceCharsToLog)).append("]");
             } catch (IOException e) {
                 sb.append(", source[_failed_to_convert_]");
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java
index fdc45530b9..a8c74101bf 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java
@@ -30,6 +30,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.text.Text;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.IndexAnalyzers;
@@ -256,8 +257,9 @@ public class DocumentMapper implements ToXContent {
         return this.objectMappers;
     }
 
+    // TODO this method looks like it is only used in tests...
     public ParsedDocument parse(String index, String type, String id, BytesReference source) throws MapperParsingException {
-        return parse(SourceToParse.source(index, type, id, source));
+        return parse(SourceToParse.source(index, type, id, source, XContentType.JSON));
     }
 
     public ParsedDocument parse(SourceToParse source) throws MapperParsingException {
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapperParser.java b/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapperParser.java
index 031f139075..be25775c13 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapperParser.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/DocumentMapperParser.java
@@ -24,9 +24,9 @@ import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
-import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.IndexAnalyzers;
 import org.elasticsearch.index.query.QueryShardContext;
@@ -80,7 +80,7 @@ public class DocumentMapperParser {
     public DocumentMapper parse(@Nullable String type, CompressedXContent source, String defaultSource) throws MapperParsingException {
         Map<String, Object> mapping = null;
         if (source != null) {
-            Map<String, Object> root = XContentHelper.convertToMap(source.compressedReference(), true).v2();
+            Map<String, Object> root = XContentHelper.convertToMap(source.compressedReference(), true, XContentType.JSON).v2();
             Tuple<String, Map<String, Object>> t = extractMapping(type, root);
             type = t.v1();
             mapping = t.v2();
@@ -162,7 +162,7 @@ public class DocumentMapperParser {
 
     private Tuple<String, Map<String, Object>> extractMapping(String type, String source) throws MapperParsingException {
         Map<String, Object> root;
-        try (XContentParser parser = XContentFactory.xContent(source).createParser(xContentRegistry, source)) {
+        try (XContentParser parser = XContentType.JSON.xContent().createParser(xContentRegistry, source)) {
             root = parser.mapOrdered();
         } catch (Exception e) {
             throw new MapperParsingException("failed to parse mapping definition", e);
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java b/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
index 014ff45200..97891b28aa 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java
@@ -154,6 +154,7 @@ final class DocumentParser {
             source.routing(),
             context.docs(),
             context.sourceToParse().source(),
+            context.sourceToParse().getXContentType(),
             update
         ).parent(source.parent());
     }
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/MapperService.java b/core/src/main/java/org/elasticsearch/index/mapper/MapperService.java
index ee4b5fea15..41b29f3c67 100755
--- a/core/src/main/java/org/elasticsearch/index/mapper/MapperService.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/MapperService.java
@@ -30,6 +30,7 @@ import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MappingMetaData;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.Setting;
@@ -37,6 +38,7 @@ import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.AbstractIndexComponent;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.IndexAnalyzers;
@@ -189,8 +191,11 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
         return this.documentParser;
     }
 
+    /**
+     * Parses the mappings (formatted as JSON) into a map
+     */
     public static Map<String, Object> parseMapping(NamedXContentRegistry xContentRegistry, String mappingSource) throws Exception {
-        try (XContentParser parser = XContentFactory.xContent(mappingSource).createParser(xContentRegistry, mappingSource)) {
+        try (XContentParser parser = XContentType.JSON.xContent().createParser(xContentRegistry, mappingSource)) {
             return parser.map();
         }
     }
@@ -318,7 +323,8 @@ public class MapperService extends AbstractIndexComponent implements Closeable {
                     && mappers.containsKey(type) == false;
 
             try {
-                DocumentMapper documentMapper = documentParser.parse(type, entry.getValue(), applyDefault ? defaultMappingSourceOrLastStored : null);
+                DocumentMapper documentMapper =
+                    documentParser.parse(type, entry.getValue(), applyDefault ? defaultMappingSourceOrLastStored : null);
                 documentMappers.add(documentMapper);
             } catch (Exception e) {
                 throw new MapperParsingException("Failed to parse mapping [{}]: {}", e, entry.getKey(), e.getMessage());
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/ParsedDocument.java b/core/src/main/java/org/elasticsearch/index/mapper/ParsedDocument.java
index db8bdf9df7..f7d5804be0 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/ParsedDocument.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/ParsedDocument.java
@@ -22,8 +22,8 @@ package org.elasticsearch.index.mapper;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.ParseContext.Document;
-import org.elasticsearch.index.mapper.SeqNoFieldMapper;
 
 import java.util.List;
 
@@ -43,6 +43,7 @@ public class ParsedDocument {
     private final List<Document> documents;
 
     private BytesReference source;
+    private XContentType xContentType;
 
     private Mapping dynamicMappingsUpdate;
 
@@ -55,6 +56,7 @@ public class ParsedDocument {
                           String routing,
                           List<Document> documents,
                           BytesReference source,
+                          XContentType xContentType,
                           Mapping dynamicMappingsUpdate) {
         this.version = version;
         this.seqID = seqID;
@@ -65,6 +67,7 @@ public class ParsedDocument {
         this.documents = documents;
         this.source = source;
         this.dynamicMappingsUpdate = dynamicMappingsUpdate;
+        this.xContentType = xContentType;
     }
 
     public BytesRef uid() {
@@ -105,8 +108,13 @@ public class ParsedDocument {
         return this.source;
     }
 
-    public void setSource(BytesReference source) {
+    public XContentType getXContentType() {
+        return this.xContentType;
+    }
+
+    public void setSource(BytesReference source, XContentType xContentType) {
         this.source = source;
+        this.xContentType = xContentType;
     }
 
     public ParsedDocument parent(String parent) {
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/SourceFieldMapper.java b/core/src/main/java/org/elasticsearch/index/mapper/SourceFieldMapper.java
index e06ec80a47..2eb2fdeaa0 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/SourceFieldMapper.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/SourceFieldMapper.java
@@ -241,7 +241,8 @@ public class SourceFieldMapper extends MetadataFieldMapper {
 
         if (filter != null) {
             // we don't update the context source if we filter, we want to keep it as is...
-            Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(source, true);
+            Tuple<XContentType, Map<String, Object>> mapTuple =
+                XContentHelper.convertToMap(source, true, context.sourceToParse().getXContentType());
             Map<String, Object> filteredSource = filter.apply(mapTuple.v2());
             BytesStreamOutput bStream = new BytesStreamOutput();
             XContentType contentType = mapTuple.v1();
diff --git a/core/src/main/java/org/elasticsearch/index/mapper/SourceToParse.java b/core/src/main/java/org/elasticsearch/index/mapper/SourceToParse.java
index 0cafc50bbe..a8a983ecde 100644
--- a/core/src/main/java/org/elasticsearch/index/mapper/SourceToParse.java
+++ b/core/src/main/java/org/elasticsearch/index/mapper/SourceToParse.java
@@ -23,15 +23,18 @@ import java.util.Objects;
 
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 
 public class SourceToParse {
 
-    public static SourceToParse source(String index, String type, String id, BytesReference source) {
-        return source(Origin.PRIMARY, index, type, id, source);
+    public static SourceToParse source(String index, String type, String id, BytesReference source, XContentType contentType) {
+        return source(Origin.PRIMARY, index, type, id, source, contentType);
     }
 
-    public static SourceToParse source(Origin origin, String index, String type, String id, BytesReference source) {
-        return new SourceToParse(origin, index, type, id, source);
+    public static SourceToParse source(Origin origin, String index, String type, String id, BytesReference source,
+                                       XContentType contentType) {
+        return new SourceToParse(origin, index, type, id, source, contentType);
     }
 
     private final Origin origin;
@@ -48,14 +51,17 @@ public class SourceToParse {
 
     private String parentId;
 
-    private SourceToParse(Origin origin, String index, String type, String id, BytesReference source) {
+    private XContentType xContentType;
+
+    private SourceToParse(Origin origin, String index, String type, String id, BytesReference source, XContentType xContentType) {
         this.origin = Objects.requireNonNull(origin);
         this.index = Objects.requireNonNull(index);
         this.type = Objects.requireNonNull(type);
         this.id = Objects.requireNonNull(id);
         // we always convert back to byte array, since we store it and Field only supports bytes..
         // so, we might as well do it here, and improve the performance of working with direct byte arrays
-        this.source = new BytesArray(source.toBytesRef());
+        this.source = new BytesArray(Objects.requireNonNull(source).toBytesRef());
+        this.xContentType = Objects.requireNonNull(xContentType);
     }
 
     public Origin origin() {
@@ -91,6 +97,10 @@ public class SourceToParse {
         return this.routing;
     }
 
+    public XContentType getXContentType() {
+        return this.xContentType;
+    }
+
     public SourceToParse routing(String routing) {
         this.routing = routing;
         return this;
diff --git a/core/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java b/core/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java
index bfb579e0c3..ee0eff2a45 100644
--- a/core/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java
+++ b/core/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java
@@ -28,6 +28,7 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.ExceptionsHelper;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.termvectors.MultiTermVectorsItemResponse;
 import org.elasticsearch.action.termvectors.MultiTermVectorsRequest;
 import org.elasticsearch.action.termvectors.MultiTermVectorsResponse;
@@ -161,6 +162,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
         private String type;
         private String id;
         private BytesReference doc;
+        private XContentType xContentType;
         private String[] fields;
         private Map<String, String> perFieldAnalyzer;
         private String routing;
@@ -178,6 +180,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             this.type = copy.type;
             this.id = copy.id;
             this.doc = copy.doc;
+            this.xContentType = copy.xContentType;
             this.fields = copy.fields;
             this.perFieldAnalyzer = copy.perFieldAnalyzer;
             this.version = copy.version;
@@ -214,6 +217,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             this.index = index;
             this.type = type;
             this.doc = doc.bytes();
+            this.xContentType = doc.contentType();
         }
 
         /**
@@ -224,6 +228,11 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             type = in.readOptionalString();
             if (in.readBoolean()) {
                 doc = (BytesReference) in.readGenericValue();
+                if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+                    xContentType = XContentType.readFrom(in);
+                } else {
+                    xContentType = XContentFactory.xContentType(doc);
+                }
             } else {
                 id = in.readString();
             }
@@ -241,6 +250,9 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             out.writeBoolean(doc != null);
             if (doc != null) {
                 out.writeGenericValue(doc);
+                if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+                    xContentType.writeTo(out);
+                }
             } else {
                 out.writeString(id);
             }
@@ -325,6 +337,10 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             return this;
         }
 
+        XContentType xContentType() {
+            return xContentType;
+        }
+
         /**
          * Convert this to a {@link TermVectorsRequest} for fetching the terms of the document.
          */
@@ -342,7 +358,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
                     .termStatistics(false);
             // for artificial docs to make sure that the id has changed in the item too
             if (doc != null) {
-                termVectorsRequest.doc(doc, true);
+                termVectorsRequest.doc(doc, true, xContentType);
                 this.id = termVectorsRequest.id();
             }
             return termVectorsRequest;
@@ -366,6 +382,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
                         item.id = parser.text();
                     } else if (Field.DOC.match(currentFieldName)) {
                         item.doc = jsonBuilder().copyCurrentStructure(parser).bytes();
+                        item.xContentType = XContentType.JSON;
                     } else if (Field.FIELDS.match(currentFieldName)) {
                         if (token == XContentParser.Token.START_ARRAY) {
                             List<String> fields = new ArrayList<>();
@@ -416,12 +433,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
                 builder.field(Field.ID.getPreferredName(), this.id);
             }
             if (this.doc != null) {
-                XContentType contentType = XContentFactory.xContentType(this.doc);
-                if (contentType == builder.contentType()) {
-                    builder.rawField(Field.DOC.getPreferredName(), this.doc);
-                } else {
-                    builder.rawField(Field.DOC.getPreferredName(), doc);
-                }
+                builder.rawField(Field.DOC.getPreferredName(), this.doc, xContentType);
             }
             if (this.fields != null) {
                 builder.array(Field.FIELDS.getPreferredName(), this.fields);
diff --git a/core/src/main/java/org/elasticsearch/index/shard/TranslogRecoveryPerformer.java b/core/src/main/java/org/elasticsearch/index/shard/TranslogRecoveryPerformer.java
index 6f4ae66a12..ad00e39097 100644
--- a/core/src/main/java/org/elasticsearch/index/shard/TranslogRecoveryPerformer.java
+++ b/core/src/main/java/org/elasticsearch/index/shard/TranslogRecoveryPerformer.java
@@ -22,6 +22,7 @@ import org.apache.logging.log4j.Logger;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.engine.IgnoreOnRecoveryEngineException;
@@ -157,7 +158,8 @@ public class TranslogRecoveryPerformer {
                     Translog.Index index = (Translog.Index) operation;
                     // we set canHaveDuplicates to true all the time such that we de-optimze the translog case and ensure that all
                     // autoGeneratedID docs that are coming from the primary are updated correctly.
-                    Engine.Index engineIndex = IndexShard.prepareIndex(docMapper(index.type()), source(shardId.getIndexName(), index.type(), index.id(), index.source())
+                    Engine.Index engineIndex = IndexShard.prepareIndex(docMapper(index.type()),
+                        source(shardId.getIndexName(), index.type(), index.id(), index.source(), XContentFactory.xContentType(index.source()))
                             .routing(index.routing()).parent(index.parent()), index.seqNo(), index.primaryTerm(),
                             index.version(), index.versionType().versionTypeForReplicationAndRecovery(), origin, index.getAutoGeneratedIdTimestamp(), true);
                     maybeAddMappingUpdate(engineIndex.type(), engineIndex.parsedDoc().dynamicMappingsUpdate(), engineIndex.id(), allowMappingUpdates);
diff --git a/core/src/main/java/org/elasticsearch/index/termvectors/TermVectorsService.java b/core/src/main/java/org/elasticsearch/index/termvectors/TermVectorsService.java
index 520cb13390..7981c89124 100644
--- a/core/src/main/java/org/elasticsearch/index/termvectors/TermVectorsService.java
+++ b/core/src/main/java/org/elasticsearch/index/termvectors/TermVectorsService.java
@@ -36,6 +36,7 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.get.GetField;
@@ -270,7 +271,8 @@ public class TermVectorsService  {
 
     private static Fields generateTermVectorsFromDoc(IndexShard indexShard, TermVectorsRequest request) throws IOException {
         // parse the document, at the moment we do update the mapping, just like percolate
-        ParsedDocument parsedDocument = parseDocument(indexShard, indexShard.shardId().getIndexName(), request.type(), request.doc());
+        ParsedDocument parsedDocument =
+            parseDocument(indexShard, indexShard.shardId().getIndexName(), request.type(), request.doc(), request.xContentType());
 
         // select the right fields and generate term vectors
         ParseContext.Document doc = parsedDocument.rootDoc();
@@ -293,13 +295,15 @@ public class TermVectorsService  {
             String[] values = doc.getValues(field.name());
             getFields.add(new GetField(field.name(), Arrays.asList((Object[]) values)));
         }
-        return generateTermVectors(indexShard, XContentHelper.convertToMap(parsedDocument.source(), true).v2(), getFields, request.offsets(), request.perFieldAnalyzer(), seenFields);
+        return generateTermVectors(indexShard, XContentHelper.convertToMap(parsedDocument.source(), true, request.xContentType()).v2(),
+            getFields, request.offsets(), request.perFieldAnalyzer(), seenFields);
     }
 
-    private static ParsedDocument parseDocument(IndexShard indexShard, String index, String type, BytesReference doc) {
+    private static ParsedDocument parseDocument(IndexShard indexShard, String index, String type, BytesReference doc,
+                                                XContentType xContentType) {
         MapperService mapperService = indexShard.mapperService();
         DocumentMapperForType docMapper = mapperService.documentMapperWithAutoCreate(type);
-        ParsedDocument parsedDocument = docMapper.getDocumentMapper().parse(source(index, type, "_id_for_tv_api", doc));
+        ParsedDocument parsedDocument = docMapper.getDocumentMapper().parse(source(index, type, "_id_for_tv_api", doc, xContentType));
         if (docMapper.getMapping() != null) {
             parsedDocument.addDynamicMappingsUpdate(docMapper.getMapping());
         }
diff --git a/core/src/main/java/org/elasticsearch/ingest/PipelineConfiguration.java b/core/src/main/java/org/elasticsearch/ingest/PipelineConfiguration.java
index 5cb9f6111f..3e874a0fd1 100644
--- a/core/src/main/java/org/elasticsearch/ingest/PipelineConfiguration.java
+++ b/core/src/main/java/org/elasticsearch/ingest/PipelineConfiguration.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.ingest;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.cluster.AbstractDiffable;
 import org.elasticsearch.cluster.Diff;
 import org.elasticsearch.common.ParseField;
@@ -29,10 +30,13 @@ import org.elasticsearch.common.xcontent.ContextParser;
 import org.elasticsearch.common.xcontent.ObjectParser;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Encapsulates a pipeline's id and configuration as a blob
@@ -45,8 +49,9 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
         PARSER.declareField((parser, builder, aVoid) -> {
             XContentBuilder contentBuilder = XContentBuilder.builder(parser.contentType().xContent());
             XContentHelper.copyCurrentStructure(contentBuilder.generator(), parser);
-            builder.setConfig(contentBuilder.bytes());
+            builder.setConfig(contentBuilder.bytes(), contentBuilder.contentType());
         }, new ParseField("config"), ObjectParser.ValueType.OBJECT);
+
     }
 
     public static ContextParser<Void, PipelineConfiguration> getParser() {
@@ -56,17 +61,19 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
 
         private String id;
         private BytesReference config;
+        private XContentType xContentType;
 
         void setId(String id) {
             this.id = id;
         }
 
-        void setConfig(BytesReference config) {
+        void setConfig(BytesReference config, XContentType xContentType) {
             this.config = config;
+            this.xContentType = xContentType;
         }
 
         PipelineConfiguration build() {
-            return new PipelineConfiguration(id, config);
+            return new PipelineConfiguration(id, config, xContentType);
         }
     }
 
@@ -75,10 +82,12 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
     // and the way the map of maps config is read requires a deep copy (it removes instead of gets entries to check for unused options)
     // also the get pipeline api just directly returns this to the caller
     private final BytesReference config;
+    private final XContentType xContentType;
 
-    public PipelineConfiguration(String id, BytesReference config) {
-        this.id = id;
-        this.config = config;
+    public PipelineConfiguration(String id, BytesReference config, XContentType xContentType) {
+        this.id = Objects.requireNonNull(id);
+        this.config = Objects.requireNonNull(config);
+        this.xContentType = Objects.requireNonNull(xContentType);
     }
 
     public String getId() {
@@ -86,7 +95,17 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
     }
 
     public Map<String, Object> getConfigAsMap() {
-        return XContentHelper.convertToMap(config, true).v2();
+        return XContentHelper.convertToMap(config, true, xContentType).v2();
+    }
+
+    // pkg-private for tests
+    XContentType getXContentType() {
+        return xContentType;
+    }
+
+    // pkg-private for tests
+    BytesReference getConfig() {
+        return config;
     }
 
     @Override
@@ -99,7 +118,13 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
     }
 
     public static PipelineConfiguration readFrom(StreamInput in) throws IOException {
-        return new PipelineConfiguration(in.readString(), in.readBytesReference());
+        if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            return new PipelineConfiguration(in.readString(), in.readBytesReference(), XContentType.readFrom(in));
+        } else {
+            final String id = in.readString();
+            final BytesReference config = in.readBytesReference();
+            return new PipelineConfiguration(id, config, XContentFactory.xContentType(config));
+        }
     }
 
     public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IOException {
@@ -110,6 +135,9 @@ public final class PipelineConfiguration extends AbstractDiffable<PipelineConfig
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(id);
         out.writeBytesReference(config);
+        if (out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            xContentType.writeTo(out);
+        }
     }
 
     @Override
diff --git a/core/src/main/java/org/elasticsearch/ingest/PipelineStore.java b/core/src/main/java/org/elasticsearch/ingest/PipelineStore.java
index 1171865a00..d476d7c2bd 100644
--- a/core/src/main/java/org/elasticsearch/ingest/PipelineStore.java
+++ b/core/src/main/java/org/elasticsearch/ingest/PipelineStore.java
@@ -162,7 +162,7 @@ public class PipelineStore extends AbstractComponent implements ClusterStateAppl
             throw new IllegalStateException("Ingest info is empty");
         }
 
-        Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false).v2();
+        Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2();
         Pipeline pipeline = factory.create(request.getId(), pipelineConfig, processorFactories);
         List<IllegalArgumentException> exceptions = new ArrayList<>();
         for (Processor processor : pipeline.flattenAllProcessors()) {
@@ -185,7 +185,7 @@ public class PipelineStore extends AbstractComponent implements ClusterStateAppl
             pipelines = new HashMap<>();
         }
 
-        pipelines.put(request.getId(), new PipelineConfiguration(request.getId(), request.getSource()));
+        pipelines.put(request.getId(), new PipelineConfiguration(request.getId(), request.getSource(), request.getXContentType()));
         ClusterState.Builder newState = ClusterState.builder(currentState);
         newState.metaData(MetaData.builder(currentState.getMetaData())
             .putCustom(IngestMetadata.TYPE, new IngestMetadata(pipelines))
diff --git a/core/src/main/java/org/elasticsearch/rest/AbstractRestChannel.java b/core/src/main/java/org/elasticsearch/rest/AbstractRestChannel.java
index 4b3505e97e..bdc78c82dd 100644
--- a/core/src/main/java/org/elasticsearch/rest/AbstractRestChannel.java
+++ b/core/src/main/java/org/elasticsearch/rest/AbstractRestChannel.java
@@ -20,7 +20,6 @@ package org.elasticsearch.rest;
 
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -58,28 +57,37 @@ public abstract class AbstractRestChannel implements RestChannel {
 
     @Override
     public XContentBuilder newBuilder() throws IOException {
-        return newBuilder(request.hasContent() ? request.content() : null, true);
+        return newBuilder(request.getXContentType(), true);
     }
 
     @Override
     public XContentBuilder newErrorBuilder() throws IOException {
         // Disable filtering when building error responses
-        return newBuilder(request.hasContent() ? request.content() : null, false);
+        return newBuilder(request.getXContentType(), false);
     }
 
+    /**
+     * Creates a new {@link XContentBuilder} for a response to be sent using this channel. The builder's type is determined by the following
+     * logic. If the request has a format parameter that will be used to attempt to map to an {@link XContentType}. If there is no format
+     * parameter, the HTTP Accept header is checked to see if it can be matched to a {@link XContentType}. If this first attempt to map
+     * fails, the request content type will be used if the value is not {@code null}; if the value is {@code null} the output format falls
+     * back to JSON.
+     */
     @Override
-    public XContentBuilder newBuilder(@Nullable BytesReference autoDetectSource, boolean useFiltering) throws IOException {
-        XContentType contentType = XContentType.fromMediaTypeOrFormat(format);
-        if (contentType == null) {
-            // try and guess it from the auto detect source
-            if (autoDetectSource != null) {
-                contentType = XContentFactory.xContentType(autoDetectSource);
+    public XContentBuilder newBuilder(@Nullable XContentType requestContentType, boolean useFiltering) throws IOException {
+        // try to determine the response content type from the media type or the format query string parameter, with the format parameter
+        // taking precedence over the Accept header
+        XContentType responseContentType = XContentType.fromMediaTypeOrFormat(format);
+        if (responseContentType == null) {
+            if (requestContentType != null) {
+                // if there was a parsed content-type for the incoming request use that since no format was specified using the query
+                // string parameter or the HTTP Accept header
+                responseContentType = requestContentType;
+            } else {
+                // default to JSON output when all else fails
+                responseContentType = XContentType.JSON;
             }
         }
-        if (contentType == null) {
-            // default to JSON
-            contentType = XContentType.JSON;
-        }
 
         Set<String> includes = Collections.emptySet();
         Set<String> excludes = Collections.emptySet();
@@ -89,7 +97,7 @@ public abstract class AbstractRestChannel implements RestChannel {
             excludes = filters.stream().filter(EXCLUDE_FILTER).map(f -> f.substring(1)).collect(toSet());
         }
 
-        XContentBuilder builder = new XContentBuilder(XContentFactory.xContent(contentType), bytesOutput(), includes, excludes);
+        XContentBuilder builder = new XContentBuilder(XContentFactory.xContent(responseContentType), bytesOutput(), includes, excludes);
         if (pretty) {
             builder.prettyPrint().lfAtEnd();
         }
@@ -125,5 +133,4 @@ public abstract class AbstractRestChannel implements RestChannel {
     public boolean detailedErrorsEnabled() {
         return detailedErrorsEnabled;
     }
-
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/BytesRestResponse.java b/core/src/main/java/org/elasticsearch/rest/BytesRestResponse.java
index 2d45bc1765..a7b709625c 100644
--- a/core/src/main/java/org/elasticsearch/rest/BytesRestResponse.java
+++ b/core/src/main/java/org/elasticsearch/rest/BytesRestResponse.java
@@ -30,6 +30,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.logging.ESLoggerFactory;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
@@ -146,6 +147,13 @@ public class BytesRestResponse extends RestResponse {
         return builder;
     }
 
+    static BytesRestResponse createSimpleErrorResponse(RestStatus status, String errorMessage) throws IOException {
+        return new BytesRestResponse(status, JsonXContent.contentBuilder().startObject()
+            .field("error", errorMessage)
+            .field("status", status.getStatus())
+            .endObject());
+    }
+
     public static ElasticsearchStatusException errorFromXContent(XContentParser parser) throws IOException {
         XContentParser.Token token = parser.nextToken();
         ensureExpectedToken(XContentParser.Token.START_OBJECT, token, parser::getTokenLocation);
diff --git a/core/src/main/java/org/elasticsearch/rest/RestChannel.java b/core/src/main/java/org/elasticsearch/rest/RestChannel.java
index 2a56313fd8..8c8346f0ef 100644
--- a/core/src/main/java/org/elasticsearch/rest/RestChannel.java
+++ b/core/src/main/java/org/elasticsearch/rest/RestChannel.java
@@ -20,9 +20,9 @@
 package org.elasticsearch.rest;
 
 import org.elasticsearch.common.Nullable;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 
@@ -35,7 +35,7 @@ public interface RestChannel {
 
     XContentBuilder newErrorBuilder() throws IOException;
 
-    XContentBuilder newBuilder(@Nullable BytesReference autoDetectSource, boolean useFiltering) throws IOException;
+    XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException;
 
     BytesStreamOutput bytesOutput();
 
@@ -47,5 +47,4 @@ public interface RestChannel {
     boolean detailedErrorsEnabled();
 
     void sendResponse(RestResponse response);
-
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/RestController.java b/core/src/main/java/org/elasticsearch/rest/RestController.java
index 5ac82b7e45..fd3587df2a 100644
--- a/core/src/main/java/org/elasticsearch/rest/RestController.java
+++ b/core/src/main/java/org/elasticsearch/rest/RestController.java
@@ -22,18 +22,19 @@ package org.elasticsearch.rest;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
 import java.util.function.UnaryOperator;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.logging.log4j.util.Supplier;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.breaker.CircuitBreaker;
 import org.elasticsearch.common.bytes.BytesArray;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.io.Streams;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
@@ -42,12 +43,15 @@ import org.elasticsearch.common.path.PathTrie;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.http.HttpServerTransport;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.http.HttpTransportSettings;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import static org.elasticsearch.rest.RestStatus.BAD_REQUEST;
 import static org.elasticsearch.rest.RestStatus.FORBIDDEN;
 import static org.elasticsearch.rest.RestStatus.INTERNAL_SERVER_ERROR;
+import static org.elasticsearch.rest.RestStatus.NOT_ACCEPTABLE;
 import static org.elasticsearch.rest.RestStatus.OK;
 
 public class RestController extends AbstractComponent {
@@ -67,6 +71,10 @@ public class RestController extends AbstractComponent {
     /** Rest headers that are copied to internal requests made during a rest request. */
     private final Set<String> headersToCopy;
 
+    private final boolean isContentTypeRequired;
+
+    private final DeprecationLogger deprecationLogger;
+
     public RestController(Settings settings, Set<String> headersToCopy, UnaryOperator<RestHandler> handlerWrapper,
                           NodeClient client, CircuitBreakerService circuitBreakerService) {
         super(settings);
@@ -77,10 +85,10 @@ public class RestController extends AbstractComponent {
         this.handlerWrapper = handlerWrapper;
         this.client = client;
         this.circuitBreakerService = circuitBreakerService;
+        this.isContentTypeRequired = HttpTransportSettings.SETTING_HTTP_CONTENT_TYPE_REQUIRED.get(settings);
+        this.deprecationLogger = new DeprecationLogger(logger);
     }
 
-
-
     /**
      * Registers a REST handler to be executed when the provided {@code method} and {@code path} match the request.
      *
@@ -165,15 +173,22 @@ public class RestController extends AbstractComponent {
         }
         RestChannel responseChannel = channel;
         try {
-            int contentLength = request.content().length();
-            if (canTripCircuitBreaker(request)) {
-                inFlightRequestsBreaker(circuitBreakerService).addEstimateBytesAndMaybeBreak(contentLength, "<http_request>");
+            final int contentLength = request.hasContent() ? request.content().length() : 0;
+            assert contentLength >= 0 : "content length was negative, how is that possible?";
+            final RestHandler handler = getHandler(request);
+
+            if (contentLength > 0 && hasContentTypeOrCanAutoDetect(request, handler) == false) {
+                sendContentTypeErrorMessage(request, responseChannel);
             } else {
-                inFlightRequestsBreaker(circuitBreakerService).addWithoutBreaking(contentLength);
+                if (canTripCircuitBreaker(request)) {
+                    inFlightRequestsBreaker(circuitBreakerService).addEstimateBytesAndMaybeBreak(contentLength, "<http_request>");
+                } else {
+                    inFlightRequestsBreaker(circuitBreakerService).addWithoutBreaking(contentLength);
+                }
+                // iff we could reserve bytes for the request we need to send the response also over this channel
+                responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength);
+                dispatchRequest(request, responseChannel, client, threadContext, handler);
             }
-            // iff we could reserve bytes for the request we need to send the response also over this channel
-            responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength);
-            dispatchRequest(request, responseChannel, client, threadContext);
         } catch (Exception e) {
             try {
                 responseChannel.sendResponse(new BytesRestResponse(channel, e));
@@ -185,33 +200,75 @@ public class RestController extends AbstractComponent {
         }
     }
 
-    void dispatchRequest(final RestRequest request, final RestChannel channel, final NodeClient client, ThreadContext threadContext) throws Exception {
-        if (!checkRequestParameters(request, channel)) {
-            return;
-        }
-        try (ThreadContext.StoredContext ignored = threadContext.stashContext()) {
-            for (String key : headersToCopy) {
-                String httpHeader = request.header(key);
-                if (httpHeader != null) {
-                    threadContext.putHeader(key, httpHeader);
+    void dispatchRequest(final RestRequest request, final RestChannel channel, final NodeClient client, ThreadContext threadContext,
+                         final RestHandler handler) throws Exception {
+        if (checkRequestParameters(request, channel) == false) {
+            channel.sendResponse(BytesRestResponse.createSimpleErrorResponse(BAD_REQUEST, "error traces in responses are disabled."));
+        } else {
+            try (ThreadContext.StoredContext ignored = threadContext.stashContext()) {
+                for (String key : headersToCopy) {
+                    String httpHeader = request.header(key);
+                    if (httpHeader != null) {
+                        threadContext.putHeader(key, httpHeader);
+                    }
                 }
-            }
 
-            final RestHandler handler = getHandler(request);
+                if (handler == null) {
+                    if (request.method() == RestRequest.Method.OPTIONS) {
+                        // when we have OPTIONS request, simply send OK by default (with the Access Control Origin header which gets automatically added)
 
-            if (handler == null) {
-                if (request.method() == RestRequest.Method.OPTIONS) {
-                    // when we have OPTIONS request, simply send OK by default (with the Access Control Origin header which gets automatically added)
-                    channel.sendResponse(new BytesRestResponse(OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
+                        channel.sendResponse(new BytesRestResponse(OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
+                    } else {
+                        final String msg = "No handler found for uri [" + request.uri() + "] and method [" + request.method() + "]";
+                        channel.sendResponse(new BytesRestResponse(BAD_REQUEST, msg));
+                    }
                 } else {
-                    final String msg = "No handler found for uri [" + request.uri() + "] and method [" + request.method() + "]";
-                    channel.sendResponse(new BytesRestResponse(BAD_REQUEST, msg));
+                    final RestHandler wrappedHandler = Objects.requireNonNull(handlerWrapper.apply(handler));
+                    wrappedHandler.handleRequest(request, channel, client);
                 }
+            }
+        }
+    }
+
+    /**
+     * If a request contains content, this method will return {@code true} if the {@code Content-Type} header is present, matches an
+     * {@link XContentType} or the request is plain text, and content type is required. If content type is not required then this method
+     * returns true unless a content type could not be inferred from the body and the rest handler does not support plain text
+     */
+    private boolean hasContentTypeOrCanAutoDetect(final RestRequest restRequest, final RestHandler restHandler) {
+        if (restRequest.getXContentType() == null) {
+            if (restHandler != null && restHandler.supportsPlainText()) {
+                // content type of null with a handler that supports plain text gets through for now. Once we remove plain text this can
+                // be removed!
+                deprecationLogger.deprecated("Plain text request bodies are deprecated. Use request parameters or body " +
+                    "in a supported format.");
+            } else if (isContentTypeRequired) {
+                return false;
             } else {
-                final RestHandler wrappedHandler = Objects.requireNonNull(handlerWrapper.apply(handler));
-                wrappedHandler.handleRequest(request, channel, client);
+                deprecationLogger.deprecated("Content type detection for rest requests is deprecated. Specify the content type using " +
+                    "the [Content-Type] header.");
+                XContentType xContentType = XContentFactory.xContentType(restRequest.content());
+                if (xContentType == null) {
+                    return false;
+                } else {
+                    restRequest.setXContentType(xContentType);
+                }
             }
         }
+        return true;
+    }
+
+    private void sendContentTypeErrorMessage(RestRequest restRequest, RestChannel channel) throws IOException {
+        final List<String> contentTypeHeader = restRequest.getAllHeaderValues("Content-Type");
+        final String errorMessage;
+        if (contentTypeHeader == null) {
+            errorMessage = "Content-Type header is missing";
+        } else {
+            errorMessage = "Content-Type header [" +
+                Strings.collectionToCommaDelimitedString(restRequest.getAllHeaderValues("Content-Type")) + "] is not supported";
+        }
+
+        channel.sendResponse(BytesRestResponse.createSimpleErrorResponse(NOT_ACCEPTABLE, errorMessage));
     }
 
     /**
@@ -222,15 +279,6 @@ public class RestController extends AbstractComponent {
         // error_trace cannot be used when we disable detailed errors
         // we consume the error_trace parameter first to ensure that it is always consumed
         if (request.paramAsBoolean("error_trace", false) && channel.detailedErrorsEnabled() == false) {
-            try {
-                XContentBuilder builder = channel.newErrorBuilder();
-                builder.startObject().field("error", "error traces in responses are disabled.").endObject().string();
-                RestResponse response = new BytesRestResponse(BAD_REQUEST, builder);
-                response.addHeader("Content-Type", "application/json");
-                channel.sendResponse(response);
-            } catch (IOException e) {
-                logger.warn("Failed to send response", e);
-            }
             return false;
         }
 
@@ -312,8 +360,8 @@ public class RestController extends AbstractComponent {
         }
 
         @Override
-        public XContentBuilder newBuilder(@Nullable BytesReference autoDetectSource, boolean useFiltering) throws IOException {
-            return delegate.newBuilder(autoDetectSource, useFiltering);
+        public XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException {
+            return delegate.newBuilder(xContentType, useFiltering);
         }
 
         @Override
diff --git a/core/src/main/java/org/elasticsearch/rest/RestHandler.java b/core/src/main/java/org/elasticsearch/rest/RestHandler.java
index 393e425baf..740b98ae73 100644
--- a/core/src/main/java/org/elasticsearch/rest/RestHandler.java
+++ b/core/src/main/java/org/elasticsearch/rest/RestHandler.java
@@ -28,7 +28,6 @@ public interface RestHandler {
 
     /**
      * Handles a rest request.
-     *
      * @param request The request to handle
      * @param channel The channel to write the request response to
      * @param client A client to use to make internal requests on behalf of the original request
@@ -38,4 +37,13 @@ public interface RestHandler {
     default boolean canTripCircuitBreaker() {
         return true;
     }
+
+    /**
+     * Indicates if a RestHandler supports plain text bodies
+     * @deprecated use request parameters or bodies that can be parsed with XContent!
+     */
+    @Deprecated
+    default boolean supportsPlainText() {
+        return false;
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/RestRequest.java b/core/src/main/java/org/elasticsearch/rest/RestRequest.java
index b4b0614f8a..7d41faf12e 100644
--- a/core/src/main/java/org/elasticsearch/rest/RestRequest.java
+++ b/core/src/main/java/org/elasticsearch/rest/RestRequest.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.rest;
 
+import org.apache.lucene.util.SetOnce;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.Booleans;
 import org.elasticsearch.common.CheckedConsumer;
@@ -26,20 +27,26 @@ import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.Tuple;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.net.SocketAddress;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
 import static org.elasticsearch.common.unit.ByteSizeValue.parseBytesSizeValue;
@@ -47,12 +54,25 @@ import static org.elasticsearch.common.unit.TimeValue.parseTimeValue;
 
 public abstract class RestRequest implements ToXContent.Params {
 
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(Loggers.getLogger(RestRequest.class));
+    // tchar pattern as defined by RFC7230 section 3.2.6
+    private static final Pattern TCHAR_PATTERN = Pattern.compile("[a-zA-z0-9!#$%&'*+\\-.\\^_`|~]+");
+
     private final NamedXContentRegistry xContentRegistry;
     private final Map<String, String> params;
+    private final Map<String, List<String>> headers;
     private final String rawPath;
     private final Set<String> consumedParams = new HashSet<>();
+    private final SetOnce<XContentType> xContentType = new SetOnce<>();
 
-    public RestRequest(NamedXContentRegistry xContentRegistry, String uri) {
+    /**
+     * Creates a new RestRequest
+     * @param xContentRegistry the xContentRegistry to use when parsing XContent
+     * @param uri the URI of the request that potentially contains request parameters
+     * @param headers a map of the headers. This map should implement a Case-Insensitive hashing for keys as HTTP header names are case
+     *                insensitive
+     */
+    public RestRequest(NamedXContentRegistry xContentRegistry, String uri, Map<String, List<String>> headers) {
         this.xContentRegistry = xContentRegistry;
         final Map<String, String> params = new HashMap<>();
         int pathEndPos = uri.indexOf('?');
@@ -63,12 +83,32 @@ public abstract class RestRequest implements ToXContent.Params {
             RestUtils.decodeQueryString(uri, pathEndPos + 1, params);
         }
         this.params = params;
+        this.headers = Collections.unmodifiableMap(headers);
+        final List<String> contentType = getAllHeaderValues("Content-Type");
+        final XContentType xContentType = parseContentType(contentType);
+        if (xContentType != null) {
+            this.xContentType.set(xContentType);
+        }
     }
 
-    public RestRequest(NamedXContentRegistry xContentRegistry, Map<String, String> params, String path) {
+    /**
+     * Creates a new RestRequest
+     * @param xContentRegistry the xContentRegistry to use when parsing XContent
+     * @param params the parameters of the request
+     * @param path the path of the request. This should not contain request parameters
+     * @param headers a map of the headers. This map should implement a Case-Insensitive hashing for keys as HTTP header names are case
+     *                insensitive
+     */
+    public RestRequest(NamedXContentRegistry xContentRegistry, Map<String, String> params, String path, Map<String, List<String>> headers) {
         this.xContentRegistry = xContentRegistry;
         this.params = params;
         this.rawPath = path;
+        this.headers = Collections.unmodifiableMap(headers);
+        final List<String> contentType = getAllHeaderValues("Content-Type");
+        final XContentType xContentType = parseContentType(contentType);
+        if (xContentType != null) {
+            this.xContentType.set(xContentType);
+        }
     }
 
     public enum Method {
@@ -100,9 +140,53 @@ public abstract class RestRequest implements ToXContent.Params {
 
     public abstract BytesReference content();
 
-    public abstract String header(String name);
+    /**
+     * Get the value of the header or {@code null} if not found. This method only retrieves the first header value if multiple values are
+     * sent. Use of {@link #getAllHeaderValues(String)} should be preferred
+     */
+    public final String header(String name) {
+        List<String> values = headers.get(name);
+        if (values != null && values.isEmpty() == false) {
+            return values.get(0);
+        }
+        return null;
+    }
+
+    /**
+     * Get all values for the header or {@code null} if the header was not found
+     */
+    public final List<String> getAllHeaderValues(String name) {
+        List<String> values = headers.get(name);
+        if (values != null) {
+            return Collections.unmodifiableList(values);
+        }
+        return null;
+    }
+
+    /**
+     * Get all of the headers and values associated with the headers. Modifications of this map are not supported.
+     */
+    public final Map<String, List<String>> getHeaders() {
+        return headers;
+    }
 
-    public abstract Iterable<Map.Entry<String, String>> headers();
+    /**
+     * The {@link XContentType} that was parsed from the {@code Content-Type} header. This value will be {@code null} in the case of
+     * a request without a valid {@code Content-Type} header, a request without content ({@link #hasContent()}, or a plain text request
+     */
+    @Nullable
+    public final XContentType getXContentType() {
+        return xContentType.get();
+    }
+
+    /**
+     * Sets the {@link XContentType}
+     * @deprecated this is only used to allow BWC with content-type detection
+     */
+    @Deprecated
+    final void setXContentType(XContentType xContentType) {
+        this.xContentType.set(xContentType);
+    }
 
     @Nullable
     public SocketAddress getRemoteAddress() {
@@ -254,8 +338,10 @@ public abstract class RestRequest implements ToXContent.Params {
         BytesReference content = content();
         if (content.length() == 0) {
             throw new ElasticsearchParseException("Body required");
+        } else if (xContentType.get() == null) {
+            throw new IllegalStateException("unknown content type");
         }
-        return XContentFactory.xContent(content).createParser(xContentRegistry, content);
+        return xContentType.get().xContent().createParser(xContentRegistry, content);
     }
 
     /**
@@ -283,11 +369,12 @@ public abstract class RestRequest implements ToXContent.Params {
      * if you need to handle the absence request content gracefully.
      */
     public final XContentParser contentOrSourceParamParser() throws IOException {
-        BytesReference content = contentOrSourceParam();
+        Tuple<XContentType, BytesReference> tuple = contentOrSourceParam();
+        BytesReference content = tuple.v2();
         if (content.length() == 0) {
             throw new ElasticsearchParseException("Body required");
         }
-        return XContentFactory.xContent(content).createParser(xContentRegistry, content);
+        return tuple.v1().xContent().createParser(xContentRegistry, content);
     }
 
     /**
@@ -296,9 +383,11 @@ public abstract class RestRequest implements ToXContent.Params {
      * back to the user when there isn't request content.
      */
     public final void withContentOrSourceParamParserOrNull(CheckedConsumer<XContentParser, IOException> withParser) throws IOException {
-        BytesReference content = contentOrSourceParam();
+        Tuple<XContentType, BytesReference> tuple = contentOrSourceParam();
+        BytesReference content = tuple.v2();
+        XContentType xContentType = tuple.v1();
         if (content.length() > 0) {
-            try (XContentParser parser = XContentFactory.xContent(content).createParser(xContentRegistry, content)) {
+            try (XContentParser parser = xContentType.xContent().createParser(xContentRegistry, content)) {
                 withParser.accept(parser);
             }
         } else {
@@ -310,7 +399,66 @@ public abstract class RestRequest implements ToXContent.Params {
      * Get the content of the request or the contents of the {@code source} param. Prefer {@link #contentOrSourceParamParser()} or
      * {@link #withContentOrSourceParamParserOrNull(CheckedConsumer)} if you need a parser.
      */
-    public final BytesReference contentOrSourceParam() {
+    public final Tuple<XContentType, BytesReference> contentOrSourceParam() {
+        if (hasContent()) {
+            if (xContentType.get() == null) {
+                throw new IllegalStateException("unknown content type");
+            }
+            return new Tuple<>(xContentType.get(), content());
+        }
+
+        String source = param("source");
+        String typeParam = param("source_content_type");
+        if (source != null) {
+            BytesArray bytes = new BytesArray(source);
+            final XContentType xContentType;
+            if (typeParam != null) {
+                xContentType = parseContentType(Collections.singletonList(typeParam));
+            } else {
+                DEPRECATION_LOGGER.deprecated("Deprecated use of the [source] parameter without the [source_content_type] parameter. Use " +
+                    "the [source_content_type] parameter to specify the content type of the source such as [application/json]");
+                xContentType = XContentFactory.xContentType(bytes);
+            }
+
+            if (xContentType == null) {
+                throw new IllegalStateException("could not determine source content type");
+            }
+            return new Tuple<>(xContentType, bytes);
+        }
+        return new Tuple<>(XContentType.JSON, BytesArray.EMPTY);
+    }
+
+    /**
+     * Call a consumer with the parser for the contents of this request if it has contents, otherwise with a parser for the {@code source}
+     * parameter if there is one, otherwise with {@code null}. Use {@link #contentOrSourceParamParser()} if you should throw an exception
+     * back to the user when there isn't request content. This version allows for plain text content
+     */
+    @Deprecated
+    public final void withContentOrSourceParamParserOrNullLenient(CheckedConsumer<XContentParser, IOException> withParser)
+        throws IOException {
+        if (hasContent() && xContentType.get() == null) {
+            withParser.accept(null);
+        }
+
+        Tuple<XContentType, BytesReference> tuple = contentOrSourceParam();
+        BytesReference content = tuple.v2();
+        XContentType xContentType = tuple.v1();
+        if (content.length() > 0) {
+            try (XContentParser parser = xContentType.xContent().createParser(xContentRegistry, content)) {
+                withParser.accept(parser);
+            }
+        } else {
+            withParser.accept(null);
+        }
+    }
+
+    /**
+     * Get the content of the request or the contents of the {@code source} param without the xcontent type. This is useful the request can
+     * accept non xcontent values.
+     * @deprecated we should only take xcontent
+     */
+    @Deprecated
+    public final BytesReference getContentOrSourceParamOnly() {
         if (hasContent()) {
             return content();
         }
@@ -320,4 +468,29 @@ public abstract class RestRequest implements ToXContent.Params {
         }
         return BytesArray.EMPTY;
     }
+
+    /**
+     * Parses the given content type string for the media type. This method currently ignores parameters.
+     */
+    // TODO stop ignoring parameters such as charset...
+    private static XContentType parseContentType(List<String> header) {
+        if (header == null || header.isEmpty()) {
+            return null;
+        } else if (header.size() > 1) {
+            throw new IllegalArgumentException("only one Content-Type header should be provided");
+        }
+
+        String rawContentType = header.get(0);
+        final String[] elements = rawContentType.split("[ \t]*;");
+        if (elements.length > 0) {
+            final String[] splitMediaType = elements[0].split("/");
+            if (splitMediaType.length == 2 && TCHAR_PATTERN.matcher(splitMediaType[0]).matches()
+                && TCHAR_PATTERN.matcher(splitMediaType[1].trim()).matches()) {
+                return XContentType.fromMediaType(elements[0]);
+            } else {
+                throw new IllegalArgumentException("invalid Content-Type header [" + rawContentType + "]");
+            }
+        }
+        throw new IllegalArgumentException("empty Content-Type header");
+    }
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestPutStoredScriptAction.java b/core/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
index cee46eba04..358c3656ce 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestPutStoredScriptAction.java
@@ -65,7 +65,7 @@ public class RestPutStoredScriptAction extends BaseRestHandler {
                 "specifying lang [" + lang + "] as part of the url path is deprecated, use request content instead");
         }
 
-        PutStoredScriptRequest putRequest = new PutStoredScriptRequest(id, lang, content);
+        PutStoredScriptRequest putRequest = new PutStoredScriptRequest(id, lang, content, request.getXContentType());
         return channel -> client.admin().cluster().putStoredScript(putRequest, new AcknowledgedRestListener<>(channel));
     }
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestCreateIndexAction.java b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestCreateIndexAction.java
index ea0cf7bf0c..8c314efee6 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestCreateIndexAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestCreateIndexAction.java
@@ -42,7 +42,7 @@ public class RestCreateIndexAction extends BaseRestHandler {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         CreateIndexRequest createIndexRequest = new CreateIndexRequest(request.param("index"));
         if (request.hasContent()) {
-            createIndexRequest.source(request.content());
+            createIndexRequest.source(request.content(), request.getXContentType());
         }
         createIndexRequest.updateAllTypes(request.paramAsBoolean("update_all_types", false));
         createIndexRequest.timeout(request.paramAsTime("timeout", createIndexRequest.timeout()));
diff --git a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutIndexTemplateAction.java b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
index c48ed3716d..b376f3dab3 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutIndexTemplateAction.java
@@ -57,7 +57,7 @@ public class RestPutIndexTemplateAction extends BaseRestHandler {
         putRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putRequest.masterNodeTimeout()));
         putRequest.create(request.paramAsBoolean("create", false));
         putRequest.cause(request.param("cause", ""));
-        putRequest.source(request.content());
+        putRequest.source(request.content(), request.getXContentType());
         return channel -> client.admin().indices().putTemplate(putRequest, new AcknowledgedRestListener<>(channel));
     }
 
diff --git a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutMappingAction.java b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutMappingAction.java
index 60c434c6b0..06fe679264 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutMappingAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestPutMappingAction.java
@@ -20,7 +20,6 @@
 package org.elasticsearch.rest.action.admin.indices;
 
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
-import org.elasticsearch.action.admin.indices.mapping.put.PutMappingResponse;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.common.Strings;
@@ -65,11 +64,11 @@ public class RestPutMappingAction extends BaseRestHandler {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         PutMappingRequest putMappingRequest = putMappingRequest(Strings.splitStringByCommaToArray(request.param("index")));
         putMappingRequest.type(request.param("type"));
-        putMappingRequest.source(request.content().utf8ToString());
+        putMappingRequest.source(request.content(), request.getXContentType());
         putMappingRequest.updateAllTypes(request.paramAsBoolean("update_all_types", false));
         putMappingRequest.timeout(request.paramAsTime("timeout", putMappingRequest.timeout()));
         putMappingRequest.masterNodeTimeout(request.paramAsTime("master_timeout", putMappingRequest.masterNodeTimeout()));
         putMappingRequest.indicesOptions(IndicesOptions.fromRequest(request, putMappingRequest.indicesOptions()));
-        return channel -> client.admin().indices().putMapping(putMappingRequest, new AcknowledgedRestListener<PutMappingResponse>(channel));
+        return channel -> client.admin().indices().putMapping(putMappingRequest, new AcknowledgedRestListener<>(channel));
     }
 }
diff --git a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestUpdateSettingsAction.java b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestUpdateSettingsAction.java
index 9e38fb5e07..47037460e2 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestUpdateSettingsAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestUpdateSettingsAction.java
@@ -66,7 +66,9 @@ public class RestUpdateSettingsAction extends BaseRestHandler {
         Settings.Builder updateSettings = Settings.builder();
         String bodySettingsStr = request.content().utf8ToString();
         if (Strings.hasText(bodySettingsStr)) {
-            Settings buildSettings = Settings.builder().loadFromSource(bodySettingsStr).build();
+            Settings buildSettings = Settings.builder()
+                .loadFromSource(bodySettingsStr, request.getXContentType())
+                .build();
             for (Map.Entry<String, String> entry : buildSettings.getAsMap().entrySet()) {
                 String key = entry.getKey();
                 String value = entry.getValue();
diff --git a/core/src/main/java/org/elasticsearch/rest/action/document/RestBulkAction.java b/core/src/main/java/org/elasticsearch/rest/action/document/RestBulkAction.java
index af0faac553..8fdf2792a4 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/document/RestBulkAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/document/RestBulkAction.java
@@ -93,7 +93,7 @@ public class RestBulkAction extends BaseRestHandler {
         bulkRequest.timeout(request.paramAsTime("timeout", BulkShardRequest.DEFAULT_TIMEOUT));
         bulkRequest.setRefreshPolicy(request.param("refresh"));
         bulkRequest.add(request.content(), defaultIndex, defaultType, defaultRouting, defaultFields,
-            defaultFetchSourceContext, defaultPipeline, null, allowExplicitIndex);
+            defaultFetchSourceContext, defaultPipeline, null, allowExplicitIndex, request.getXContentType());
 
         return channel -> client.bulk(bulkRequest, new RestBuilderListener<BulkResponse>(channel) {
             @Override
diff --git a/core/src/main/java/org/elasticsearch/rest/action/document/RestGetSourceAction.java b/core/src/main/java/org/elasticsearch/rest/action/document/RestGetSourceAction.java
index 728e1ff599..83d424ed74 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/document/RestGetSourceAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/document/RestGetSourceAction.java
@@ -66,7 +66,7 @@ public class RestGetSourceAction extends BaseRestHandler {
                 client.get(getRequest, new RestResponseListener<GetResponse>(channel) {
                     @Override
                     public RestResponse buildResponse(GetResponse response) throws Exception {
-                        XContentBuilder builder = channel.newBuilder(response.getSourceInternal(), false);
+                        XContentBuilder builder = channel.newBuilder(request.getXContentType(), false);
                         if (response.isSourceEmpty()) { // check if doc source (or doc itself) is missing
                             return new BytesRestResponse(NOT_FOUND, builder);
                         } else {
diff --git a/core/src/main/java/org/elasticsearch/rest/action/document/RestIndexAction.java b/core/src/main/java/org/elasticsearch/rest/action/document/RestIndexAction.java
index 042b0d57b5..ddaf226875 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/document/RestIndexAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/document/RestIndexAction.java
@@ -65,7 +65,7 @@ public class RestIndexAction extends BaseRestHandler {
         indexRequest.routing(request.param("routing"));
         indexRequest.parent(request.param("parent")); // order is important, set it after routing, so it will set the routing
         indexRequest.setPipeline(request.param("pipeline"));
-        indexRequest.source(request.content());
+        indexRequest.source(request.content(), request.getXContentType());
         indexRequest.timeout(request.paramAsTime("timeout", IndexRequest.DEFAULT_TIMEOUT));
         indexRequest.setRefreshPolicy(request.param("refresh"));
         indexRequest.version(RestActions.parseVersion(request));
diff --git a/core/src/main/java/org/elasticsearch/rest/action/ingest/RestPutPipelineAction.java b/core/src/main/java/org/elasticsearch/rest/action/ingest/RestPutPipelineAction.java
index b7a8e6366b..2496c9b4a2 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/ingest/RestPutPipelineAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/ingest/RestPutPipelineAction.java
@@ -21,7 +21,10 @@ package org.elasticsearch.rest.action.ingest;
 
 import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.client.node.NodeClient;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
@@ -38,7 +41,8 @@ public class RestPutPipelineAction extends BaseRestHandler {
 
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
-        PutPipelineRequest request = new PutPipelineRequest(restRequest.param("id"), restRequest.contentOrSourceParam());
+        Tuple<XContentType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
+        PutPipelineRequest request = new PutPipelineRequest(restRequest.param("id"), sourceTuple.v2(), sourceTuple.v1());
         request.masterNodeTimeout(restRequest.paramAsTime("master_timeout", request.masterNodeTimeout()));
         request.timeout(restRequest.paramAsTime("timeout", request.timeout()));
         return channel -> client.admin().cluster().putPipeline(request, new AcknowledgedRestListener<>(channel));
diff --git a/core/src/main/java/org/elasticsearch/rest/action/ingest/RestSimulatePipelineAction.java b/core/src/main/java/org/elasticsearch/rest/action/ingest/RestSimulatePipelineAction.java
index 5885dc9df6..9dbe1808a8 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/ingest/RestSimulatePipelineAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/ingest/RestSimulatePipelineAction.java
@@ -21,7 +21,10 @@ package org.elasticsearch.rest.action.ingest;
 
 import org.elasticsearch.action.ingest.SimulatePipelineRequest;
 import org.elasticsearch.client.node.NodeClient;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
@@ -40,7 +43,8 @@ public class RestSimulatePipelineAction extends BaseRestHandler {
 
     @Override
     public RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
-        SimulatePipelineRequest request = new SimulatePipelineRequest(restRequest.contentOrSourceParam());
+        Tuple<XContentType, BytesReference> sourceTuple = restRequest.contentOrSourceParam();
+        SimulatePipelineRequest request = new SimulatePipelineRequest(sourceTuple.v2(), sourceTuple.v1());
         request.setId(restRequest.param("id"));
         request.setVerbose(restRequest.paramAsBoolean("verbose", false));
         return channel -> client.admin().cluster().simulatePipeline(request, new RestToXContentListener<>(channel));
diff --git a/core/src/main/java/org/elasticsearch/rest/action/search/RestClearScrollAction.java b/core/src/main/java/org/elasticsearch/rest/action/search/RestClearScrollAction.java
index e7ee7c7397..47252f5a10 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/search/RestClearScrollAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/search/RestClearScrollAction.java
@@ -20,12 +20,10 @@
 package org.elasticsearch.rest.action.search;
 
 import org.elasticsearch.action.search.ClearScrollRequest;
-import org.elasticsearch.action.search.ClearScrollResponse;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
@@ -50,26 +48,34 @@ public class RestClearScrollAction extends BaseRestHandler {
         String scrollIds = request.param("scroll_id");
         ClearScrollRequest clearRequest = new ClearScrollRequest();
         clearRequest.setScrollIds(Arrays.asList(splitScrollIds(scrollIds)));
-        BytesReference body = request.contentOrSourceParam();
-        if (body.length() > 0) {
-            if (XContentFactory.xContentType(body) == null) {
-                scrollIds = body.utf8ToString();
-                clearRequest.setScrollIds(Arrays.asList(splitScrollIds(scrollIds)));
+        request.withContentOrSourceParamParserOrNullLenient((xContentParser -> {
+            if (xContentParser == null) {
+                if (request.hasContent()) {
+                    // TODO: why do we accept this plain text value? maybe we can just use the scroll params?
+                    BytesReference body = request.content();
+                    String bodyScrollIds = body.utf8ToString();
+                    clearRequest.setScrollIds(Arrays.asList(splitScrollIds(bodyScrollIds)));
+                }
             } else {
                 // NOTE: if rest request with xcontent body has request parameters, these parameters does not override xcontent value
                 clearRequest.setScrollIds(null);
-                try (XContentParser parser = request.contentOrSourceParamParser()) {
-                    buildFromContent(parser, clearRequest);
+                try {
+                    buildFromContent(xContentParser, clearRequest);
                 } catch (IOException e) {
                     throw new IllegalArgumentException("Failed to parse request body", e);
                 }
             }
-        }
+        }));
 
-        return channel -> client.clearScroll(clearRequest, new RestStatusToXContentListener<ClearScrollResponse>(channel));
+        return channel -> client.clearScroll(clearRequest, new RestStatusToXContentListener<>(channel));
+    }
+
+    @Override
+    public boolean supportsPlainText() {
+        return true;
     }
 
-    public static String[] splitScrollIds(String scrollIds) {
+    private static String[] splitScrollIds(String scrollIds) {
         if (scrollIds == null) {
             return Strings.EMPTY_ARRAY;
         }
diff --git a/core/src/main/java/org/elasticsearch/rest/action/search/RestMultiSearchAction.java b/core/src/main/java/org/elasticsearch/rest/action/search/RestMultiSearchAction.java
index 567823a6e2..a803958618 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/search/RestMultiSearchAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/search/RestMultiSearchAction.java
@@ -26,10 +26,11 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContent;
-import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryParseContext;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
@@ -93,7 +94,7 @@ public class RestMultiSearchAction extends BaseRestHandler {
     }
 
     /**
-     * Parses a multi-line {@link RestRequest} body, instanciating a {@link SearchRequest} for each line and applying the given consumer.
+     * Parses a multi-line {@link RestRequest} body, instantiating a {@link SearchRequest} for each line and applying the given consumer.
      */
     public static void parseMultiLineRequest(RestRequest request, IndicesOptions indicesOptions, boolean allowExplicitIndex,
             BiConsumer<SearchRequest, XContentParser> consumer) throws IOException {
@@ -103,9 +104,10 @@ public class RestMultiSearchAction extends BaseRestHandler {
         String searchType = request.param("search_type");
         String routing = request.param("routing");
 
-        final BytesReference data = request.contentOrSourceParam();
+        final Tuple<XContentType, BytesReference> sourceTuple = request.contentOrSourceParam();
+        final XContent xContent = sourceTuple.v1().xContent();
+        final BytesReference data = sourceTuple.v2();
 
-        XContent xContent = XContentFactory.xContent(data);
         int from = 0;
         int length = data.length();
         byte marker = xContent.streamSeparator();
@@ -176,7 +178,7 @@ public class RestMultiSearchAction extends BaseRestHandler {
                 break;
             }
             BytesReference bytes = data.slice(from, nextMarker - from);
-            try (XContentParser parser = XContentFactory.xContent(bytes).createParser(request.getXContentRegistry(), bytes)) {
+            try (XContentParser parser = xContent.createParser(request.getXContentRegistry(), bytes)) {
                 consumer.accept(searchRequest, parser);
             }
             // move pointers
diff --git a/core/src/main/java/org/elasticsearch/rest/action/search/RestSearchScrollAction.java b/core/src/main/java/org/elasticsearch/rest/action/search/RestSearchScrollAction.java
index 87a6f464cc..2a60fc6317 100644
--- a/core/src/main/java/org/elasticsearch/rest/action/search/RestSearchScrollAction.java
+++ b/core/src/main/java/org/elasticsearch/rest/action/search/RestSearchScrollAction.java
@@ -24,7 +24,6 @@ import org.elasticsearch.client.node.NodeClient;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
@@ -58,25 +57,33 @@ public class RestSearchScrollAction extends BaseRestHandler {
             searchScrollRequest.scroll(new Scroll(parseTimeValue(scroll, null, "scroll")));
         }
 
-        BytesReference body = request.contentOrSourceParam();
-        if (body.length() > 0) {
-            if (XContentFactory.xContentType(body) == null) {
-                if (scrollId == null) {
-                    scrollId = body.utf8ToString();
-                    searchScrollRequest.scrollId(scrollId);
+        request.withContentOrSourceParamParserOrNull(xContentParser -> {
+            if (xContentParser == null) {
+                if (request.hasContent()) {
+                    // TODO: why do we accept this plain text value? maybe we can just use the scroll params?
+                    BytesReference body = request.getContentOrSourceParamOnly();
+                    if (scrollId == null) {
+                        String bodyScrollId = body.utf8ToString();
+                        searchScrollRequest.scrollId(bodyScrollId);
+                    }
                 }
             } else {
                 // NOTE: if rest request with xcontent body has request parameters, these parameters override xcontent values
-                try (XContentParser parser = request.contentOrSourceParamParser()) {
-                    buildFromContent(parser, searchScrollRequest);
+                try {
+                    buildFromContent(xContentParser, searchScrollRequest);
                 } catch (IOException e) {
                     throw new IllegalArgumentException("Failed to parse request body", e);
                 }
             }
-        }
+        });
         return channel -> client.searchScroll(searchScrollRequest, new RestStatusToXContentListener<>(channel));
     }
 
+    @Override
+    public boolean supportsPlainText() {
+        return true;
+    }
+
     public static void buildFromContent(XContentParser parser, SearchScrollRequest searchScrollRequest) throws IOException {
         if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
             throw new IllegalArgumentException("Malformed content, must start with an object");
diff --git a/core/src/main/java/org/elasticsearch/script/ScriptMetaData.java b/core/src/main/java/org/elasticsearch/script/ScriptMetaData.java
index e9fb6e126f..87afc21a8c 100644
--- a/core/src/main/java/org/elasticsearch/script/ScriptMetaData.java
+++ b/core/src/main/java/org/elasticsearch/script/ScriptMetaData.java
@@ -276,7 +276,6 @@ public final class ScriptMetaData implements MetaData.Custom, Writeable, ToXCont
                     } else {
                         source = new StoredScriptSource(id.substring(0, split), parser.text(), Collections.emptyMap());
                     }
-
                     scripts.put(id, source);
 
                     id = null;
diff --git a/core/src/main/java/org/elasticsearch/script/ScriptService.java b/core/src/main/java/org/elasticsearch/script/ScriptService.java
index f9bcc77ab4..692e081a7b 100644
--- a/core/src/main/java/org/elasticsearch/script/ScriptService.java
+++ b/core/src/main/java/org/elasticsearch/script/ScriptService.java
@@ -389,7 +389,7 @@ public class ScriptService extends AbstractComponent implements Closeable, Clust
                 request.content().length() + "] for script [" + request.id() + "]");
         }
 
-        StoredScriptSource source = StoredScriptSource.parse(request.lang(), request.content());
+        StoredScriptSource source = StoredScriptSource.parse(request.lang(), request.content(), request.xContentType());
 
         if (isLangSupported(source.getLang()) == false) {
             throw new IllegalArgumentException("unable to put stored script with unsupported lang [" + source.getLang() + "]");
diff --git a/core/src/main/java/org/elasticsearch/script/StoredScriptSource.java b/core/src/main/java/org/elasticsearch/script/StoredScriptSource.java
index 69fc1ed34c..e6c5b09362 100644
--- a/core/src/main/java/org/elasticsearch/script/StoredScriptSource.java
+++ b/core/src/main/java/org/elasticsearch/script/StoredScriptSource.java
@@ -40,6 +40,7 @@ import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentParser.Token;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
@@ -231,8 +232,8 @@ public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> imp
      * @param content The content from the request to be parsed as described above.
      * @return        The parsed {@link StoredScriptSource}.
      */
-    public static StoredScriptSource parse(String lang, BytesReference content) {
-        try (XContentParser parser = XContentHelper.createParser(NamedXContentRegistry.EMPTY, content)) {
+    public static StoredScriptSource parse(String lang, BytesReference content, XContentType xContentType) {
+        try (XContentParser parser = xContentType.xContent().createParser(NamedXContentRegistry.EMPTY, content)) {
             Token token = parser.nextToken();
 
             if (token != Token.START_OBJECT) {
diff --git a/core/src/test/java/org/elasticsearch/action/IndicesRequestIT.java b/core/src/test/java/org/elasticsearch/action/IndicesRequestIT.java
index 791501373e..cca9d73b78 100644
--- a/core/src/test/java/org/elasticsearch/action/IndicesRequestIT.java
+++ b/core/src/test/java/org/elasticsearch/action/IndicesRequestIT.java
@@ -75,6 +75,7 @@ import org.elasticsearch.action.termvectors.TermVectorsRequest;
 import org.elasticsearch.action.update.UpdateAction;
 import org.elasticsearch.action.update.UpdateRequest;
 import org.elasticsearch.action.update.UpdateResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.settings.Settings;
@@ -203,7 +204,8 @@ public class IndicesRequestIT extends ESIntegTestCase {
         String[] indexShardActions = new String[]{BulkAction.NAME + "[s][p]", BulkAction.NAME + "[s][r]"};
         interceptTransportActions(indexShardActions);
 
-        IndexRequest indexRequest = new IndexRequest(randomIndexOrAlias(), "type", "id").source("field", "value");
+        IndexRequest indexRequest = new IndexRequest(randomIndexOrAlias(), "type", "id")
+            .source(Requests.INDEX_CONTENT_TYPE, "field", "value");
         internalCluster().coordOnlyNodeClient().index(indexRequest).actionGet();
 
         clearInterceptedActions();
@@ -228,7 +230,7 @@ public class IndicesRequestIT extends ESIntegTestCase {
 
         String indexOrAlias = randomIndexOrAlias();
         client().prepareIndex(indexOrAlias, "type", "id").setSource("field", "value").get();
-        UpdateRequest updateRequest = new UpdateRequest(indexOrAlias, "type", "id").doc("field1", "value1");
+        UpdateRequest updateRequest = new UpdateRequest(indexOrAlias, "type", "id").doc(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
         UpdateResponse updateResponse = internalCluster().coordOnlyNodeClient().update(updateRequest).actionGet();
         assertEquals(DocWriteResponse.Result.UPDATED, updateResponse.getResult());
 
@@ -242,7 +244,8 @@ public class IndicesRequestIT extends ESIntegTestCase {
         interceptTransportActions(updateShardActions);
 
         String indexOrAlias = randomIndexOrAlias();
-        UpdateRequest updateRequest = new UpdateRequest(indexOrAlias, "type", "id").upsert("field", "value").doc("field1", "value1");
+        UpdateRequest updateRequest = new UpdateRequest(indexOrAlias, "type", "id").upsert(Requests.INDEX_CONTENT_TYPE, "field", "value")
+            .doc(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
         UpdateResponse updateResponse = internalCluster().coordOnlyNodeClient().update(updateRequest).actionGet();
         assertEquals(DocWriteResponse.Result.CREATED, updateResponse.getResult());
 
@@ -275,7 +278,7 @@ public class IndicesRequestIT extends ESIntegTestCase {
         int numIndexRequests = iterations(1, 10);
         for (int i = 0; i < numIndexRequests; i++) {
             String indexOrAlias = randomIndexOrAlias();
-            bulkRequest.add(new IndexRequest(indexOrAlias, "type", "id").source("field", "value"));
+            bulkRequest.add(new IndexRequest(indexOrAlias, "type", "id").source(Requests.INDEX_CONTENT_TYPE, "field", "value"));
             indices.add(indexOrAlias);
         }
         int numDeleteRequests = iterations(1, 10);
@@ -287,7 +290,7 @@ public class IndicesRequestIT extends ESIntegTestCase {
         int numUpdateRequests = iterations(1, 10);
         for (int i = 0; i < numUpdateRequests; i++) {
             String indexOrAlias = randomIndexOrAlias();
-            bulkRequest.add(new UpdateRequest(indexOrAlias, "type", "id").doc("field1", "value1"));
+            bulkRequest.add(new UpdateRequest(indexOrAlias, "type", "id").doc(Requests.INDEX_CONTENT_TYPE, "field1", "value1"));
             indices.add(indexOrAlias);
         }
 
diff --git a/core/src/test/java/org/elasticsearch/action/ListenerActionIT.java b/core/src/test/java/org/elasticsearch/action/ListenerActionIT.java
index 60e4b4d262..d0e8d997a1 100644
--- a/core/src/test/java/org/elasticsearch/action/ListenerActionIT.java
+++ b/core/src/test/java/org/elasticsearch/action/ListenerActionIT.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.index.IndexResponse;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.client.transport.TransportClient;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -38,7 +39,7 @@ public class ListenerActionIT extends ESIntegTestCase {
         IndexRequest request = new IndexRequest("test", "type", "1");
         if (randomBoolean()) {
             // set the source, without it, we will have a verification failure
-            request.source("field1", "value1");
+            request.source(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
         }
 
         client.index(request, new ActionListener<IndexResponse>() {
diff --git a/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TasksIT.java b/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TasksIT.java
index 7f490ebab9..580d8149fd 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TasksIT.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TasksIT.java
@@ -50,6 +50,7 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.search.builder.SearchSourceBuilder;
@@ -300,7 +301,8 @@ public class TasksIT extends ESIntegTestCase {
         registerTaskManageListeners(BulkAction.NAME + "[s][r]");  // shard task on replica
         createIndex("test");
         ensureGreen("test"); // Make sure all shards are allocated to catch replication tasks
-        client().prepareBulk().add(client().prepareIndex("test", "doc", "test_id").setSource("{\"foo\": \"bar\"}")).get();
+        client().prepareBulk().add(client().prepareIndex("test", "doc", "test_id")
+            .setSource("{\"foo\": \"bar\"}", XContentType.JSON)).get();
 
         // the bulk operation should produce one main task
         List<TaskInfo> topTask = findEvents(BulkAction.NAME, Tuple::v1);
@@ -352,7 +354,7 @@ public class TasksIT extends ESIntegTestCase {
         registerTaskManageListeners(SearchAction.NAME + "[*]");  // shard task
         createIndex("test");
         ensureGreen("test"); // Make sure all shards are allocated to catch replication tasks
-        client().prepareIndex("test", "doc", "test_id").setSource("{\"foo\": \"bar\"}")
+        client().prepareIndex("test", "doc", "test_id").setSource("{\"foo\": \"bar\"}", XContentType.JSON)
             .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE).get();
 
         assertSearchResponse(client().prepareSearch("test").setTypes("doc").setQuery(QueryBuilders.matchAllQuery()).get());
diff --git a/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java b/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
index fbe0302e5d..1e9256d20e 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/cluster/node/tasks/TransportTasksActionTests.java
@@ -801,6 +801,6 @@ public class TransportTasksActionTests extends TaskManagerTestCase {
         builder.endObject();
         builder.flush();
         logger.info(builder.string());
-        return XContentHelper.convertToMap(builder.bytes(), false).v2();
+        return XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java b/core/src/test/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
index 546b1435c3..4b531267d3 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java
@@ -209,7 +209,7 @@ public class ClusterRerouteRequestTests extends ESTestCase {
         FakeRestRequest.Builder requestBuilder = new FakeRestRequest.Builder(xContentRegistry());
         requestBuilder.withParams(params);
         if (hasBody) {
-            requestBuilder.withContent(builder.bytes());
+            requestBuilder.withContent(builder.bytes(), builder.contentType());
         }
         return requestBuilder.build();
     }
diff --git a/core/src/test/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java b/core/src/test/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java
new file mode 100644
index 0000000000..5f3e107942
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptRequestTests.java
@@ -0,0 +1,72 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.action.admin.cluster.storedscripts;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.util.Base64;
+
+public class PutStoredScriptRequestTests extends ESTestCase {
+
+    public void testSerialization() throws IOException {
+        PutStoredScriptRequest storedScriptRequest = new PutStoredScriptRequest("foo", "bar", new BytesArray("{}"), XContentType.JSON);
+
+        assertEquals(XContentType.JSON, storedScriptRequest.xContentType());
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            storedScriptRequest.writeTo(output);
+
+            try (StreamInput in = output.bytes().streamInput()) {
+                PutStoredScriptRequest serialized = new PutStoredScriptRequest();
+                serialized.readFrom(in);
+                assertEquals(XContentType.JSON, serialized.xContentType());
+                assertEquals(storedScriptRequest.lang(), serialized.lang());
+                assertEquals(storedScriptRequest.id(), serialized.id());
+            }
+        }
+    }
+
+    public void testSerializationBwc() throws IOException {
+        final byte[] rawStreamBytes = Base64.getDecoder().decode("ADwDCG11c3RhY2hlAQZzY3JpcHQCe30A");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(rawStreamBytes)) {
+            in.setVersion(version);
+            PutStoredScriptRequest serialized = new PutStoredScriptRequest();
+            serialized.readFrom(in);
+            assertEquals(XContentType.JSON, serialized.xContentType());
+            assertEquals("mustache", serialized.lang());
+            assertEquals("script", serialized.id());
+            assertEquals(new BytesArray("{}"), serialized.content());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                serialized.writeTo(out);
+                out.flush();
+                assertArrayEquals(rawStreamBytes, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+}
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
index ad17689bb7..1ae60f42eb 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestBuilderTests.java
@@ -22,6 +22,7 @@ package org.elasticsearch.action.admin.indices.create;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.client.NoOpClient;
 import org.junit.After;
@@ -57,7 +58,7 @@ public class CreateIndexRequestBuilderTests extends ESTestCase {
      */
     public void testSetSource() throws IOException {
         CreateIndexRequestBuilder builder = new CreateIndexRequestBuilder(this.testClient, CreateIndexAction.INSTANCE);
-        builder.setSource("{\""+KEY+"\" : \""+VALUE+"\"}");
+        builder.setSource("{\""+KEY+"\" : \""+VALUE+"\"}", XContentType.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         XContentBuilder xContent = XContentFactory.jsonBuilder().startObject().field(KEY, VALUE).endObject();
@@ -68,7 +69,7 @@ public class CreateIndexRequestBuilderTests extends ESTestCase {
         ByteArrayOutputStream docOut = new ByteArrayOutputStream();
         XContentBuilder doc = XContentFactory.jsonBuilder(docOut).startObject().field(KEY, VALUE).endObject();
         doc.close();
-        builder.setSource(docOut.toByteArray());
+        builder.setSource(docOut.toByteArray(), XContentType.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         Map<String, String> settingsMap = new HashMap<>();
@@ -85,7 +86,7 @@ public class CreateIndexRequestBuilderTests extends ESTestCase {
         builder.setSettings(KEY, VALUE);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
-        builder.setSettings("{\""+KEY+"\" : \""+VALUE+"\"}");
+        builder.setSettings("{\""+KEY+"\" : \""+VALUE+"\"}", XContentType.JSON);
         assertEquals(VALUE, builder.request().settings().get(KEY));
 
         builder.setSettings(Settings.builder().put(KEY, VALUE));
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java
new file mode 100644
index 0000000000..590eba3666
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequestTests.java
@@ -0,0 +1,72 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.action.admin.indices.create;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.common.xcontent.json.JsonXContent;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.util.Base64;
+
+public class CreateIndexRequestTests extends ESTestCase {
+
+    public void testSerialization() throws IOException {
+        CreateIndexRequest request = new CreateIndexRequest("foo");
+        String mapping = JsonXContent.contentBuilder().startObject().startObject("type").endObject().endObject().string();
+        request.mapping("my_type", mapping, XContentType.JSON);
+
+        try (BytesStreamOutput output = new BytesStreamOutput()) {
+            request.writeTo(output);
+
+            try (StreamInput in = output.bytes().streamInput()) {
+                CreateIndexRequest serialized = new CreateIndexRequest();
+                serialized.readFrom(in);
+                assertEquals(request.index(), serialized.index());
+                assertEquals(mapping, serialized.mappings().get("my_type"));
+            }
+        }
+    }
+
+    public void testSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("ADwDAANmb28APAMBB215X3R5cGULeyJ0eXBlIjp7fX0AAAD////+AA==");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            CreateIndexRequest serialized = new CreateIndexRequest();
+            serialized.readFrom(in);
+            assertEquals("foo", serialized.index());
+            BytesReference bytesReference = JsonXContent.contentBuilder().startObject().startObject("type").endObject().endObject().bytes();
+            assertEquals(bytesReference.utf8ToString(), serialized.mappings().get("my_type"));
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                serialized.writeTo(out);
+                out.flush();
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+}
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/create/ShrinkIndexIT.java b/core/src/test/java/org/elasticsearch/action/admin/indices/create/ShrinkIndexIT.java
index e19f930a22..9ab6551d6f 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/indices/create/ShrinkIndexIT.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/create/ShrinkIndexIT.java
@@ -32,6 +32,7 @@ import org.elasticsearch.cluster.routing.UnassignedInfo;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.TermsQueryBuilder;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -59,7 +60,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
         internalCluster().ensureAtLeastNumDataNodes(2);
         prepareCreate("source").setSettings(Settings.builder().put(indexSettings()).put("number_of_shards", shardSplits[0])).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", "t1", Integer.toString(i)).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("source", "t1", Integer.toString(i))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
             .getDataNodes();
@@ -85,7 +87,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
         assertHitCount(client().prepareSearch("first_shrink").setSize(100).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 20);
 
         for (int i = 0; i < 20; i++) { // now update
-            client().prepareIndex("first_shrink", "t1", Integer.toString(i)).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("first_shrink", "t1", Integer.toString(i))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         flushAndRefresh();
         assertHitCount(client().prepareSearch("first_shrink").setSize(100).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 20);
@@ -113,7 +116,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
         assertHitCount(client().prepareSearch("second_shrink").setSize(100).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 20);
 
         for (int i = 0; i < 20; i++) { // now update
-            client().prepareIndex("second_shrink", "t1", Integer.toString(i)).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("second_shrink", "t1", Integer.toString(i))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         flushAndRefresh();
         assertHitCount(client().prepareSearch("second_shrink").setSize(100).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 20);
@@ -129,7 +133,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
             .put("index.version.created", version)
         ).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", randomFrom("t1", "t2", "t3")).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("source", randomFrom("t1", "t2", "t3"))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
             .getDataNodes();
@@ -164,7 +169,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
         }
 
         for (int i = 20; i < 40; i++) {
-            client().prepareIndex("target", randomFrom("t1", "t2", "t3")).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("target", randomFrom("t1", "t2", "t3"))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         flushAndRefresh();
         assertHitCount(client().prepareSearch("target").setSize(100).setQuery(new TermsQueryBuilder("foo", "bar")).get(), 40);
@@ -181,7 +187,8 @@ public class ShrinkIndexIT extends ESIntegTestCase {
             .put("number_of_shards", randomIntBetween(2, 7))
             .put("number_of_replicas", 0)).get();
         for (int i = 0; i < 20; i++) {
-            client().prepareIndex("source", randomFrom("t1", "t2", "t3")).setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}").get();
+            client().prepareIndex("source", randomFrom("t1", "t2", "t3"))
+                .setSource("{\"foo\" : \"bar\", \"i\" : " + i + "}", XContentType.JSON).get();
         }
         ImmutableOpenMap<String, DiscoveryNode> dataNodes = client().admin().cluster().prepareState().get().getState().nodes()
             .getDataNodes();
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java
new file mode 100644
index 0000000000..4dc396323c
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponseTests.java
@@ -0,0 +1,52 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.action.admin.indices.mapping.get;
+
+import org.elasticsearch.action.admin.indices.mapping.get.GetFieldMappingsResponse.FieldMappingMetaData;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+public class GetFieldMappingsResponseTests extends ESTestCase {
+
+    public void testSerialization() throws IOException {
+        Map<String, Map<String, Map<String, FieldMappingMetaData>>> mappings = new HashMap<>();
+        FieldMappingMetaData fieldMappingMetaData = new FieldMappingMetaData("my field", new BytesArray("{}"));
+        mappings.put("index", Collections.singletonMap("type", Collections.singletonMap("field", fieldMappingMetaData)));
+        GetFieldMappingsResponse response = new GetFieldMappingsResponse(mappings);
+
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            response.writeTo(out);
+            GetFieldMappingsResponse serialized = new GetFieldMappingsResponse();
+            try (StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes)) {
+                serialized.readFrom(in);
+                FieldMappingMetaData metaData = serialized.fieldMappings("index", "type", "field");
+                assertNotNull(metaData);
+                assertEquals(new BytesArray("{}"), metaData.getSource());
+            }
+        }
+    }
+}
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
index 9c93e5c73d..fd7f830e59 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequestTests.java
@@ -19,10 +19,20 @@
 
 package org.elasticsearch.action.admin.indices.mapping.put;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.common.xcontent.yaml.YamlXContent;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.test.ESTestCase;
 
+import java.io.IOException;
+import java.util.Base64;
+
 public class PutMappingRequestTests extends ESTestCase {
 
     public void testValidation() {
@@ -41,12 +51,12 @@ public class PutMappingRequestTests extends ESTestCase {
         assertNotNull("source validation should fail", ex);
         assertTrue(ex.getMessage().contains("source is missing"));
 
-        r.source("");
+        r.source("", XContentType.JSON);
         ex = r.validate();
         assertNotNull("source validation should fail", ex);
         assertTrue(ex.getMessage().contains("source is empty"));
 
-        r.source("somevalidmapping");
+        r.source("somevalidmapping", XContentType.JSON);
         ex = r.validate();
         assertNull("validation should succeed", ex);
 
@@ -64,4 +74,33 @@ public class PutMappingRequestTests extends ESTestCase {
                 () -> PutMappingRequest.buildFromSimplifiedDef("type", "only_field"));
         assertEquals("mapping source must be pairs of fieldnames and properties definition.", e.getMessage());
     }
+
+    public void testPutMappingRequestSerialization() throws IOException {
+        PutMappingRequest request = new PutMappingRequest("foo");
+        String mapping = YamlXContent.contentBuilder().startObject().field("foo", "bar").endObject().string();
+        request.source(mapping, XContentType.YAML);
+        assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), request.source());
+
+        BytesStreamOutput bytesStreamOutput = new BytesStreamOutput();
+        request.writeTo(bytesStreamOutput);
+        StreamInput in = StreamInput.wrap(bytesStreamOutput.bytes().toBytesRef().bytes);
+        PutMappingRequest serialized = new PutMappingRequest();
+        serialized.readFrom(in);
+
+        String source = serialized.source();
+        assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), source);
+    }
+
+    public void testSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("ADwDAQNmb28MAA8tLS0KZm9vOiAiYmFyIgoAPAMAAAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            PutMappingRequest request = new PutMappingRequest();
+            request.readFrom(in);
+            String mapping = YamlXContent.contentBuilder().startObject().field("foo", "bar").endObject().string();
+            assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), request.source());
+        }
+    }
 }
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/template/BWCTemplateTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/template/BWCTemplateTests.java
index 7ea103313f..3615ea10c3 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/indices/template/BWCTemplateTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/template/BWCTemplateTests.java
@@ -19,9 +19,10 @@
 
 package org.elasticsearch.action.admin.indices.template;
 
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 
-import static org.elasticsearch.test.StreamsUtils.copyToStringFromClasspath;
+import static org.elasticsearch.test.StreamsUtils.copyToBytesFromClasspath;
 
 /**
  * Rudimentary tests that the templates used by Logstash and Beats
@@ -29,14 +30,14 @@ import static org.elasticsearch.test.StreamsUtils.copyToStringFromClasspath;
  */
 public class BWCTemplateTests extends ESSingleNodeTestCase {
     public void testBeatsTemplatesBWC() throws Exception {
-        String metricBeat = copyToStringFromClasspath("/org/elasticsearch/action/admin/indices/template/metricbeat-5.0.template.json");
-        String packetBeat = copyToStringFromClasspath("/org/elasticsearch/action/admin/indices/template/packetbeat-5.0.template.json");
-        String fileBeat = copyToStringFromClasspath("/org/elasticsearch/action/admin/indices/template/filebeat-5.0.template.json");
-        String winLogBeat = copyToStringFromClasspath("/org/elasticsearch/action/admin/indices/template/winlogbeat-5.0.template.json");
-        client().admin().indices().preparePutTemplate("metricbeat").setSource(metricBeat).get();
-        client().admin().indices().preparePutTemplate("packetbeat").setSource(packetBeat).get();
-        client().admin().indices().preparePutTemplate("filebeat").setSource(fileBeat).get();
-        client().admin().indices().preparePutTemplate("winlogbeat").setSource(winLogBeat).get();
+        byte[] metricBeat = copyToBytesFromClasspath("/org/elasticsearch/action/admin/indices/template/metricbeat-5.0.template.json");
+        byte[] packetBeat = copyToBytesFromClasspath("/org/elasticsearch/action/admin/indices/template/packetbeat-5.0.template.json");
+        byte[] fileBeat = copyToBytesFromClasspath("/org/elasticsearch/action/admin/indices/template/filebeat-5.0.template.json");
+        byte[] winLogBeat = copyToBytesFromClasspath("/org/elasticsearch/action/admin/indices/template/winlogbeat-5.0.template.json");
+        client().admin().indices().preparePutTemplate("metricbeat").setSource(metricBeat, XContentType.JSON).get();
+        client().admin().indices().preparePutTemplate("packetbeat").setSource(packetBeat, XContentType.JSON).get();
+        client().admin().indices().preparePutTemplate("filebeat").setSource(fileBeat, XContentType.JSON).get();
+        client().admin().indices().preparePutTemplate("winlogbeat").setSource(winLogBeat, XContentType.JSON).get();
 
         client().prepareIndex("metricbeat-foo", "doc", "1").setSource("message", "foo").get();
         client().prepareIndex("packetbeat-foo", "doc", "1").setSource("message", "foo").get();
@@ -46,8 +47,8 @@ public class BWCTemplateTests extends ESSingleNodeTestCase {
     }
 
     public void testLogstashTemplatesBWC() throws Exception {
-        String ls5x = copyToStringFromClasspath("/org/elasticsearch/action/admin/indices/template/logstash-5.0.template.json");
-        client().admin().indices().preparePutTemplate("logstash-5x").setSource(ls5x).get();
+        byte[] ls5x = copyToBytesFromClasspath("/org/elasticsearch/action/admin/indices/template/logstash-5.0.template.json");
+        client().admin().indices().preparePutTemplate("logstash-5x").setSource(ls5x, XContentType.JSON).get();
         client().prepareIndex("logstash-foo", "doc", "1").setSource("message", "foo").get();
         assertWarnings("Deprecated field [template] used, replaced by [index_patterns]");
     }
diff --git a/core/src/test/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java b/core/src/test/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
index 076245ad76..48b2ae79cf 100644
--- a/core/src/test/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestTests.java
@@ -22,6 +22,9 @@ import org.elasticsearch.Version;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.common.xcontent.yaml.YamlXContent;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
@@ -66,4 +69,36 @@ public class PutIndexTemplateRequestTests extends ESTestCase {
         }
     }
 
+    public void testPutIndexTemplateRequestSerializationXContent() throws IOException {
+        PutIndexTemplateRequest request = new PutIndexTemplateRequest("foo");
+        String mapping = YamlXContent.contentBuilder().startObject().field("foo", "bar").endObject().string();
+        request.patterns(Collections.singletonList("foo"));
+        request.mapping("bar", mapping, XContentType.YAML);
+        assertNotEquals(mapping, request.mappings().get("bar"));
+        assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), request.mappings().get("bar"));
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        request.writeTo(out);
+
+        StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes);
+        PutIndexTemplateRequest serialized = new PutIndexTemplateRequest();
+        serialized.readFrom(in);
+        assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), serialized.mappings().get("bar"));
+    }
+
+    public void testPutIndexTemplateRequestSerializationXContentBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("ADwDAANmb28IdGVtcGxhdGUAAAAAAAABA2Jhcg8tLS0KZm9vOiAiYmFyIgoAAAAAAAAAAAAAAAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            PutIndexTemplateRequest request = new PutIndexTemplateRequest();
+            request.readFrom(in);
+            String mapping = YamlXContent.contentBuilder().startObject().field("foo", "bar").endObject().string();
+            assertNotEquals(mapping, request.mappings().get("bar"));
+            assertEquals(XContentHelper.convertToJson(new BytesArray(mapping), false, XContentType.YAML), request.mappings().get("bar"));
+            assertEquals("foo", request.name());
+            assertEquals("template", request.patterns().get(0));
+        }
+    }
 }
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkIntegrationIT.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkIntegrationIT.java
index 4300a629fb..22377ea176 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkIntegrationIT.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkIntegrationIT.java
@@ -21,6 +21,7 @@
 package org.elasticsearch.action.bulk;
 
 import org.elasticsearch.action.admin.indices.mapping.get.GetMappingsResponse;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import java.nio.charset.StandardCharsets;
@@ -31,7 +32,7 @@ public class BulkIntegrationIT extends ESIntegTestCase {
     public void testBulkIndexCreatesMapping() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/bulk-log.json");
         BulkRequestBuilder bulkBuilder = client().prepareBulk();
-        bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkBuilder.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         bulkBuilder.get();
         assertBusy(new Runnable() {
             @Override
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorClusterSettingsIT.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorClusterSettingsIT.java
index 48d989209c..ca1630b006 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorClusterSettingsIT.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorClusterSettingsIT.java
@@ -20,6 +20,7 @@
 package org.elasticsearch.action.bulk;
 
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
 import org.elasticsearch.test.ESIntegTestCase.Scope;
@@ -36,9 +37,9 @@ public class BulkProcessorClusterSettingsIT extends ESIntegTestCase {
         client().admin().cluster().prepareHealth("willwork").setWaitForGreenStatus().execute().actionGet();
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("willwork", "type1", "1").setSource("{\"foo\":1}"));
-        bulkRequestBuilder.add(client().prepareIndex("wontwork", "type1", "2").setSource("{\"foo\":2}"));
-        bulkRequestBuilder.add(client().prepareIndex("willwork", "type1", "3").setSource("{\"foo\":3}"));
+        bulkRequestBuilder.add(client().prepareIndex("willwork", "type1", "1").setSource("{\"foo\":1}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("wontwork", "type1", "2").setSource("{\"foo\":2}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("willwork", "type1", "3").setSource("{\"foo\":3}", XContentType.JSON));
         BulkResponse br = bulkRequestBuilder.get();
         BulkItemResponse[] responses = br.getItems();
         assertEquals(3, responses.length);
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorIT.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorIT.java
index 6bac7c2f8a..7e608815c4 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorIT.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkProcessorIT.java
@@ -25,6 +25,7 @@ import org.elasticsearch.action.get.MultiGetRequestBuilder;
 import org.elasticsearch.action.get.MultiGetResponse;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
@@ -254,11 +255,13 @@ public class BulkProcessorIT extends ESIntegTestCase {
             for (int i = 1; i <= numDocs; i++) {
                 if (randomBoolean()) {
                     testDocs++;
-                    processor.add(new IndexRequest("test", "test", Integer.toString(testDocs)).source("field", "value"));
+                    processor.add(new IndexRequest("test", "test", Integer.toString(testDocs))
+                        .source(Requests.INDEX_CONTENT_TYPE, "field", "value"));
                     multiGetRequestBuilder.add("test", "test", Integer.toString(testDocs));
                 } else {
                     testReadOnlyDocs++;
-                    processor.add(new IndexRequest("test-ro", "test", Integer.toString(testReadOnlyDocs)).source("field", "value"));
+                    processor.add(new IndexRequest("test-ro", "test", Integer.toString(testReadOnlyDocs))
+                        .source(Requests.INDEX_CONTENT_TYPE, "field", "value"));
                 }
             }
         }
@@ -296,7 +299,8 @@ public class BulkProcessorIT extends ESIntegTestCase {
     private static MultiGetRequestBuilder indexDocs(Client client, BulkProcessor processor, int numDocs) {
         MultiGetRequestBuilder multiGetRequestBuilder = client.prepareMultiGet();
         for (int i = 1; i <= numDocs; i++) {
-            processor.add(new IndexRequest("test", "test", Integer.toString(i)).source("field", randomRealisticUnicodeOfLengthBetween(1, 30)));
+            processor.add(new IndexRequest("test", "test", Integer.toString(i))
+                .source(Requests.INDEX_CONTENT_TYPE, "field", randomRealisticUnicodeOfLengthBetween(1, 30)));
             multiGetRequestBuilder.add("test", "test", Integer.toString(i));
         }
         return multiGetRequestBuilder;
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestModifierTests.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestModifierTests.java
index 4a41499d0d..b6242e6d5f 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestModifierTests.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestModifierTests.java
@@ -29,6 +29,7 @@ import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.DocWriteRequest;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.index.IndexResponse;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.test.ESTestCase;
 import org.hamcrest.Matchers;
@@ -44,7 +45,7 @@ public class BulkRequestModifierTests extends ESTestCase {
         int numRequests = scaledRandomIntBetween(8, 64);
         BulkRequest bulkRequest = new BulkRequest();
         for (int i = 0; i < numRequests; i++) {
-            bulkRequest.add(new IndexRequest("_index", "_type", String.valueOf(i)).source("{}"));
+            bulkRequest.add(new IndexRequest("_index", "_type", String.valueOf(i)).source("{}", XContentType.JSON));
         }
         CaptureActionListener actionListener = new CaptureActionListener();
         TransportBulkAction.BulkRequestModifier bulkRequestModifier = new TransportBulkAction.BulkRequestModifier(bulkRequest);
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestTests.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestTests.java
index e0c58a60d2..a35a82ff09 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkRequestTests.java
@@ -61,7 +61,7 @@ public class BulkRequestTests extends ESTestCase {
             bulkAction = Strings.replace(bulkAction, "\r\n", "\n");
         }
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
         assertThat(((IndexRequest) bulkRequest.requests().get(0)).source(), equalTo(new BytesArray("{ \"field1\" : \"value1\" }")));
         assertThat(bulkRequest.requests().get(1), instanceOf(DeleteRequest.class));
@@ -71,21 +71,21 @@ public class BulkRequestTests extends ESTestCase {
     public void testSimpleBulk2() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk2.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
     }
 
     public void testSimpleBulk3() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk3.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(3));
     }
 
     public void testSimpleBulk4() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk4.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(4));
         assertThat(((UpdateRequest) bulkRequest.requests().get(0)).id(), equalTo("1"));
         assertThat(((UpdateRequest) bulkRequest.requests().get(0)).retryOnConflict(), equalTo(2));
@@ -107,21 +107,21 @@ public class BulkRequestTests extends ESTestCase {
     public void testBulkAllowExplicitIndex() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk.json");
         try {
-            new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), null, null, false);
+            new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), null, null, false, XContentType.JSON);
             fail();
         } catch (Exception e) {
 
         }
 
         bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk5.json");
-        new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), "test", null, false);
+        new BulkRequest().add(new BytesArray(bulkAction.getBytes(StandardCharsets.UTF_8)), "test", null, false, XContentType.JSON);
     }
 
     public void testBulkAddIterable() {
         BulkRequest bulkRequest = Requests.bulkRequest();
         List<DocWriteRequest> requests = new ArrayList<>();
-        requests.add(new IndexRequest("test", "test", "id").source("field", "value"));
-        requests.add(new UpdateRequest("test", "test", "id").doc("field", "value"));
+        requests.add(new IndexRequest("test", "test", "id").source(Requests.INDEX_CONTENT_TYPE, "field", "value"));
+        requests.add(new UpdateRequest("test", "test", "id").doc(Requests.INDEX_CONTENT_TYPE, "field", "value"));
         requests.add(new DeleteRequest("test", "test", "id"));
         bulkRequest.add(requests);
         assertThat(bulkRequest.requests().size(), equalTo(3));
@@ -134,7 +134,7 @@ public class BulkRequestTests extends ESTestCase {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk6.json");
         BulkRequest bulkRequest = new BulkRequest();
         ParsingException exc = expectThrows(ParsingException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null));
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON));
         assertThat(exc.getMessage(), containsString("Unknown key for a VALUE_STRING in [hello]"));
     }
 
@@ -142,7 +142,7 @@ public class BulkRequestTests extends ESTestCase {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk7.json");
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null));
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON));
         assertThat(exc.getMessage(),
             containsString("Malformed action/metadata line [5], expected a simple value for field [_unkown] but found [START_ARRAY]"));
     }
@@ -151,7 +151,7 @@ public class BulkRequestTests extends ESTestCase {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk8.json");
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null));
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON));
         assertThat(exc.getMessage(), containsString("Action/metadata line [3] contains an unknown parameter [_foo]"));
     }
 
@@ -159,14 +159,14 @@ public class BulkRequestTests extends ESTestCase {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk9.json");
         BulkRequest bulkRequest = new BulkRequest();
         IllegalArgumentException exc = expectThrows(IllegalArgumentException.class,
-            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null));
+            () -> bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON));
         assertThat(exc.getMessage(), containsString("Malformed action/metadata line [3], expected START_OBJECT or END_OBJECT but found [START_ARRAY]"));
     }
 
     public void testSimpleBulk10() throws Exception {
         String bulkAction = copyToStringFromClasspath("/org/elasticsearch/action/bulk/simple-bulk10.json");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         assertThat(bulkRequest.numberOfActions(), equalTo(9));
     }
 
@@ -178,8 +178,8 @@ public class BulkRequestTests extends ESTestCase {
         // We force here a "type is missing" validation error
         bulkRequest.add(new DeleteRequest("index", null, "id"));
         bulkRequest.add(new DeleteRequest("index", "type", "id").setRefreshPolicy(RefreshPolicy.IMMEDIATE));
-        bulkRequest.add(new UpdateRequest("index", "type", "id").doc("{}").setRefreshPolicy(RefreshPolicy.IMMEDIATE));
-        bulkRequest.add(new IndexRequest("index", "type", "id").source("{}").setRefreshPolicy(RefreshPolicy.IMMEDIATE));
+        bulkRequest.add(new UpdateRequest("index", "type", "id").doc("{}", XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
+        bulkRequest.add(new IndexRequest("index", "type", "id").source("{}", XContentType.JSON).setRefreshPolicy(RefreshPolicy.IMMEDIATE));
         ActionRequestValidationException validate = bulkRequest.validate();
         assertThat(validate, notNullValue());
         assertThat(validate.validationErrors(), not(empty()));
@@ -202,7 +202,8 @@ public class BulkRequestTests extends ESTestCase {
         assertThat(validate.validationErrors(), not(empty()));
         assertThat(validate.validationErrors(), contains(
                 "script or doc is missing",
-                "source is missing"));
+                "source is missing",
+                "content type is missing"));
     }
 
     public void testCannotAddNullRequests() throws Exception {
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java b/core/src/test/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java
index 82eee3554e..b31426e397 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/BulkWithUpdatesIT.java
@@ -29,8 +29,10 @@ import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
 import org.elasticsearch.action.update.UpdateRequest;
 import org.elasticsearch.action.update.UpdateRequestBuilder;
 import org.elasticsearch.action.update.UpdateResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.plugins.Plugin;
@@ -209,9 +211,9 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
         assertThat(bulkResponse.getItems()[2].getResponse().getVersion(), equalTo(2L));
 
         bulkResponse = client().prepareBulk()
-                .add(client().prepareUpdate("test", "type", "1").setVersion(4L).setDoc("field", "2"))
-                .add(client().prepareUpdate("test", "type", "2").setDoc("field", "2"))
-                .add(client().prepareUpdate("test", "type", "1").setVersion(2L).setDoc("field", "3")).get();
+                .add(client().prepareUpdate("test", "type", "1").setVersion(4L).setDoc(Requests.INDEX_CONTENT_TYPE, "field", "2"))
+                .add(client().prepareUpdate("test", "type", "2").setDoc(Requests.INDEX_CONTENT_TYPE, "field", "2"))
+                .add(client().prepareUpdate("test", "type", "1").setVersion(2L).setDoc(Requests.INDEX_CONTENT_TYPE, "field", "3")).get();
 
         assertThat(bulkResponse.getItems()[0].getFailureMessage(), containsString("version conflict"));
         assertThat(bulkResponse.getItems()[1].getResponse().getVersion(), equalTo(2L));
@@ -235,9 +237,9 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
 
         bulkResponse = client().prepareBulk()
                 .add(client().prepareUpdate("test", "type", "e1")
-                        .setDoc("field", "2").setVersion(10)) // INTERNAL
+                        .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "2").setVersion(10)) // INTERNAL
                 .add(client().prepareUpdate("test", "type", "e1")
-                        .setDoc("field", "3").setVersion(13).setVersionType(VersionType.INTERNAL))
+                        .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "3").setVersion(13).setVersionType(VersionType.INTERNAL))
                 .get();
 
         assertThat(bulkResponse.getItems()[0].getFailureMessage(), containsString("version conflict"));
@@ -493,8 +495,8 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
                 "}" +
                 "\n").array();
 
-        builder.add(addParent, 0, addParent.length);
-        builder.add(addChild, 0, addChild.length);
+        builder.add(addParent, 0, addParent.length, XContentType.JSON);
+        builder.add(addChild, 0, addChild.length, XContentType.JSON);
 
         BulkResponse bulkResponse = builder.get();
         assertThat(bulkResponse.getItems().length, equalTo(2));
@@ -576,9 +578,9 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
                 "}" +
                 "\n").array();
 
-        builder.add(addParent, 0, addParent.length);
-        builder.add(addChild1, 0, addChild1.length);
-        builder.add(addChild2, 0, addChild2.length);
+        builder.add(addParent, 0, addParent.length, XContentType.JSON);
+        builder.add(addChild1, 0, addChild1.length, XContentType.JSON);
+        builder.add(addChild2, 0, addChild2.length, XContentType.JSON);
 
         BulkResponse bulkResponse = builder.get();
         assertThat(bulkResponse.getItems().length, equalTo(3));
@@ -650,10 +652,10 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
                 "}" +
                 "\n").array();
 
-        builder.add(addParent, 0, addParent.length);
-        builder.add(addChildOK, 0, addChildOK.length);
-        builder.add(addChildMissingRouting, 0, addChildMissingRouting.length);
-        builder.add(addChildOK, 0, addChildOK.length);
+        builder.add(addParent, 0, addParent.length, XContentType.JSON);
+        builder.add(addChildOK, 0, addChildOK.length, XContentType.JSON);
+        builder.add(addChildMissingRouting, 0, addChildMissingRouting.length, XContentType.JSON);
+        builder.add(addChildOK, 0, addChildOK.length, XContentType.JSON);
 
         BulkResponse bulkResponse = builder.get();
         assertThat(bulkResponse.getItems().length, equalTo(4));
@@ -680,7 +682,8 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
                     return;
                 }
                 BulkRequestBuilder requestBuilder = client().prepareBulk();
-                requestBuilder.add(client().prepareUpdate("test", "type", "1").setVersion(1).setDoc("field", threadID));
+                requestBuilder.add(client().prepareUpdate("test", "type", "1").setVersion(1)
+                    .setDoc(Requests.INDEX_CONTENT_TYPE, "field", threadID));
                 responses[threadID] = requestBuilder.get();
 
             });
@@ -733,19 +736,19 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
     // issue 6630
     public void testThatFailedUpdateRequestReturnsCorrectType() throws Exception {
         BulkResponse indexBulkItemResponse = client().prepareBulk()
-                .add(new IndexRequest("test", "type", "3").source("{ \"title\" : \"Great Title of doc 3\" }"))
-                .add(new IndexRequest("test", "type", "4").source("{ \"title\" : \"Great Title of doc 4\" }"))
-                .add(new IndexRequest("test", "type", "5").source("{ \"title\" : \"Great Title of doc 5\" }"))
-                .add(new IndexRequest("test", "type", "6").source("{ \"title\" : \"Great Title of doc 6\" }"))
+                .add(new IndexRequest("test", "type", "3").source("{ \"title\" : \"Great Title of doc 3\" }", XContentType.JSON))
+                .add(new IndexRequest("test", "type", "4").source("{ \"title\" : \"Great Title of doc 4\" }", XContentType.JSON))
+                .add(new IndexRequest("test", "type", "5").source("{ \"title\" : \"Great Title of doc 5\" }", XContentType.JSON))
+                .add(new IndexRequest("test", "type", "6").source("{ \"title\" : \"Great Title of doc 6\" }", XContentType.JSON))
                 .setRefreshPolicy(RefreshPolicy.IMMEDIATE)
                 .get();
         assertNoFailures(indexBulkItemResponse);
 
         BulkResponse bulkItemResponse = client().prepareBulk()
-                .add(new IndexRequest("test", "type", "1").source("{ \"title\" : \"Great Title of doc 1\" }"))
-                .add(new IndexRequest("test", "type", "2").source("{ \"title\" : \"Great Title of doc 2\" }"))
-                .add(new UpdateRequest("test", "type", "3").doc("{ \"date\" : \"2014-01-30T23:59:57\"}"))
-                .add(new UpdateRequest("test", "type", "4").doc("{ \"date\" : \"2014-13-30T23:59:57\"}"))
+                .add(new IndexRequest("test", "type", "1").source("{ \"title\" : \"Great Title of doc 1\" }", XContentType.JSON))
+                .add(new IndexRequest("test", "type", "2").source("{ \"title\" : \"Great Title of doc 2\" }", XContentType.JSON))
+                .add(new UpdateRequest("test", "type", "3").doc("{ \"date\" : \"2014-01-30T23:59:57\"}", XContentType.JSON))
+                .add(new UpdateRequest("test", "type", "4").doc("{ \"date\" : \"2014-13-30T23:59:57\"}", XContentType.JSON))
                 .add(new DeleteRequest("test", "type", "5"))
                 .add(new DeleteRequest("test", "type", "6"))
         .get();
@@ -768,10 +771,10 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
     public void testThatMissingIndexDoesNotAbortFullBulkRequest() throws Exception{
         createIndex("bulkindex1", "bulkindex2");
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(new IndexRequest("bulkindex1", "index1_type", "1").source("text", "hallo1"))
-                   .add(new IndexRequest("bulkindex2", "index2_type", "1").source("text", "hallo2"))
-                   .add(new IndexRequest("bulkindex2", "index2_type").source("text", "hallo2"))
-                   .add(new UpdateRequest("bulkindex2", "index2_type", "2").doc("foo", "bar"))
+        bulkRequest.add(new IndexRequest("bulkindex1", "index1_type", "1").source(Requests.INDEX_CONTENT_TYPE, "text", "hallo1"))
+                   .add(new IndexRequest("bulkindex2", "index2_type", "1").source(Requests.INDEX_CONTENT_TYPE, "text", "hallo2"))
+                   .add(new IndexRequest("bulkindex2", "index2_type").source(Requests.INDEX_CONTENT_TYPE, "text", "hallo2"))
+                   .add(new UpdateRequest("bulkindex2", "index2_type", "2").doc(Requests.INDEX_CONTENT_TYPE, "foo", "bar"))
                    .add(new DeleteRequest("bulkindex2", "index2_type", "3"))
                    .setRefreshPolicy(RefreshPolicy.IMMEDIATE);
 
@@ -794,8 +797,8 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
         assertAcked(client().admin().indices().prepareClose("bulkindex1"));
 
         BulkRequest bulkRequest = new BulkRequest().setRefreshPolicy(RefreshPolicy.IMMEDIATE);
-        bulkRequest.add(new IndexRequest("bulkindex1", "index1_type", "1").source("text", "hallo1"))
-                .add(new UpdateRequest("bulkindex1", "index1_type", "1").doc("foo", "bar"))
+        bulkRequest.add(new IndexRequest("bulkindex1", "index1_type", "1").source(Requests.INDEX_CONTENT_TYPE, "text", "hallo1"))
+                .add(new UpdateRequest("bulkindex1", "index1_type", "1").doc(Requests.INDEX_CONTENT_TYPE, "foo", "bar"))
                 .add(new DeleteRequest("bulkindex1", "index1_type", "1"));
 
         BulkResponse bulkResponse = client().bulk(bulkRequest).get();
@@ -810,8 +813,10 @@ public class BulkWithUpdatesIT extends ESIntegTestCase {
     // issue 9821
     public void testInvalidIndexNamesCorrectOpType() {
         BulkResponse bulkResponse = client().prepareBulk()
-                .add(client().prepareIndex().setIndex("INVALID.NAME").setType("type1").setId("1").setSource("field", 1))
-                .add(client().prepareUpdate().setIndex("INVALID.NAME").setType("type1").setId("1").setDoc("field", randomInt()))
+                .add(client().prepareIndex().setIndex("INVALID.NAME").setType("type1").setId("1")
+                    .setSource(Requests.INDEX_CONTENT_TYPE, "field", 1))
+                .add(client().prepareUpdate().setIndex("INVALID.NAME").setType("type1").setId("1")
+                    .setDoc(Requests.INDEX_CONTENT_TYPE, "field", randomInt()))
                 .add(client().prepareDelete().setIndex("INVALID.NAME").setType("type1").setId("1")).get();
         assertThat(bulkResponse.getItems().length, is(3));
         assertThat(bulkResponse.getItems()[0].getOpType(), is(OpType.INDEX));
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/TransportBulkActionTookTests.java b/core/src/test/java/org/elasticsearch/action/bulk/TransportBulkActionTookTests.java
index 29c55c426d..cdfe54575f 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/TransportBulkActionTookTests.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/TransportBulkActionTookTests.java
@@ -35,6 +35,7 @@ import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.AtomicArray;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.tasks.Task;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.transport.CapturingTransport;
@@ -174,7 +175,7 @@ public class TransportBulkActionTookTests extends ESTestCase {
             bulkAction = Strings.replace(bulkAction, "\r\n", "\n");
         }
         BulkRequest bulkRequest = new BulkRequest();
-        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null);
+        bulkRequest.add(bulkAction.getBytes(StandardCharsets.UTF_8), 0, bulkAction.length(), null, null, XContentType.JSON);
         AtomicLong expected = new AtomicLong();
         TransportBulkAction action = createAction(controlled, expected);
         action.doExecute(null, bulkRequest, new ActionListener<BulkResponse>() {
diff --git a/core/src/test/java/org/elasticsearch/action/bulk/byscroll/AsyncBulkByScrollActionTests.java b/core/src/test/java/org/elasticsearch/action/bulk/byscroll/AsyncBulkByScrollActionTests.java
index 4b4f24f5b8..b740563411 100644
--- a/core/src/test/java/org/elasticsearch/action/bulk/byscroll/AsyncBulkByScrollActionTests.java
+++ b/core/src/test/java/org/elasticsearch/action/bulk/byscroll/AsyncBulkByScrollActionTests.java
@@ -68,6 +68,7 @@ import org.elasticsearch.common.text.Text;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
 import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.engine.VersionConflictEngineException;
 import org.elasticsearch.index.shard.ShardId;
@@ -388,7 +389,7 @@ public class AsyncBulkByScrollActionTests extends ESTestCase {
             }
         };
         ScrollableHitSource.BasicHit hit = new ScrollableHitSource.BasicHit("index", "type", "id", 0);
-        hit.setSource(new BytesArray("{}"));
+        hit.setSource(new BytesArray("{}"), XContentType.JSON);
         ScrollableHitSource.Response response = new ScrollableHitSource.Response(false, emptyList(), 1, singletonList(hit), null);
         simulateScrollResponse(action, timeValueNanos(System.nanoTime()), 0, response);
         ExecutionException e = expectThrows(ExecutionException.class, () -> listener.get());
diff --git a/core/src/test/java/org/elasticsearch/action/index/IndexRequestBuilderTests.java b/core/src/test/java/org/elasticsearch/action/index/IndexRequestBuilderTests.java
index 06e9d586e3..5341588f72 100644
--- a/core/src/test/java/org/elasticsearch/action/index/IndexRequestBuilderTests.java
+++ b/core/src/test/java/org/elasticsearch/action/index/IndexRequestBuilderTests.java
@@ -74,8 +74,9 @@ public class IndexRequestBuilderTests extends ESTestCase {
         ByteArrayOutputStream docOut = new ByteArrayOutputStream();
         XContentBuilder doc = XContentFactory.jsonBuilder(docOut).startObject().field("SomeKey", "SomeValue").endObject();
         doc.close();
-        indexRequestBuilder.setSource(docOut.toByteArray());
-        assertEquals(EXPECTED_SOURCE, XContentHelper.convertToJson(indexRequestBuilder.request().source(), true));
+        indexRequestBuilder.setSource(docOut.toByteArray(), XContentType.JSON);
+        assertEquals(EXPECTED_SOURCE, XContentHelper.convertToJson(indexRequestBuilder.request().source(), true,
+            indexRequestBuilder.request().getContentType()));
 
         doc = XContentFactory.jsonBuilder().startObject().field("SomeKey", "SomeValue").endObject();
         doc.close();
diff --git a/core/src/test/java/org/elasticsearch/action/index/IndexRequestTests.java b/core/src/test/java/org/elasticsearch/action/index/IndexRequestTests.java
index a722529626..fb1991bcd9 100644
--- a/core/src/test/java/org/elasticsearch/action/index/IndexRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/index/IndexRequestTests.java
@@ -18,17 +18,24 @@
  */
 package org.elasticsearch.action.index;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.DocWriteRequest;
 import org.elasticsearch.action.support.ActiveShardCount;
 import org.elasticsearch.action.support.replication.ReplicationResponse;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.seqno.SequenceNumbersService;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.test.ESTestCase;
 
+import java.io.IOException;
 import java.util.Arrays;
+import java.util.Base64;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -83,19 +90,19 @@ public class IndexRequestTests extends ESTestCase {
     public void testIndexingRejectsLongIds() {
         String id = randomAsciiOfLength(511);
         IndexRequest request = new IndexRequest("index", "type", id);
-        request.source("{}");
+        request.source("{}", XContentType.JSON);
         ActionRequestValidationException validate = request.validate();
         assertNull(validate);
 
         id = randomAsciiOfLength(512);
         request = new IndexRequest("index", "type", id);
-        request.source("{}");
+        request.source("{}", XContentType.JSON);
         validate = request.validate();
         assertNull(validate);
 
         id = randomAsciiOfLength(513);
         request = new IndexRequest("index", "type", id);
-        request.source("{}");
+        request.source("{}", XContentType.JSON);
         validate = request.validate();
         assertThat(validate, notNullValue());
         assertThat(validate.getMessage(),
@@ -150,4 +157,49 @@ public class IndexRequestTests extends ESTestCase {
                 ",shards={\"total\":" + total + ",\"successful\":" + successful + ",\"failed\":0}]",
                 indexResponse.toString());
     }
+
+    public void testIndexRequestXContentSerialization() throws IOException {
+        IndexRequest indexRequest = new IndexRequest("foo", "bar", "1");
+        indexRequest.source("{}", XContentType.JSON);
+        assertEquals(XContentType.JSON, indexRequest.getContentType());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        indexRequest.writeTo(out);
+        StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes);
+        IndexRequest serialized = new IndexRequest();
+        serialized.readFrom(in);
+        assertEquals(XContentType.JSON, serialized.getContentType());
+        assertEquals(new BytesArray("{}"), serialized.source());
+    }
+
+    public void testIndexRequestXContentSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("AAD////+AgQDZm9vAAAAAQNiYXIBATEAAAAAAnt9AP/////////9AAAA//////////8AAAAAAAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            IndexRequest serialized = new IndexRequest();
+            serialized.readFrom(in);
+            assertEquals(XContentType.JSON, serialized.getContentType());
+            assertEquals("{}", serialized.source().utf8ToString());
+            // don't test writing to earlier versions since output differs due to no timestamp
+        }
+    }
+
+    // reindex makes use of index requests without a source so this needs to be handled
+    public void testSerializationOfEmptyRequestWorks() throws IOException {
+        IndexRequest request = new IndexRequest("index", "type");
+        assertNull(request.getContentType());
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            request.writeTo(out);
+
+            try (StreamInput in = out.bytes().streamInput()) {
+                IndexRequest serialized = new IndexRequest();
+                serialized.readFrom(in);
+                assertNull(request.getContentType());
+                assertEquals("index", request.index());
+                assertEquals("type", request.type());
+            }
+        }
+    }
 }
diff --git a/core/src/test/java/org/elasticsearch/action/ingest/PutPipelineRequestTests.java b/core/src/test/java/org/elasticsearch/action/ingest/PutPipelineRequestTests.java
new file mode 100644
index 0000000000..01aed87947
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/action/ingest/PutPipelineRequestTests.java
@@ -0,0 +1,67 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.action.ingest;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+public class PutPipelineRequestTests extends ESTestCase {
+
+    public void testSerializationWithXContent() throws IOException {
+        PutPipelineRequest request = new PutPipelineRequest("1", new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
+        assertEquals(XContentType.JSON, request.getXContentType());
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        request.writeTo(output);
+        StreamInput in = StreamInput.wrap(output.bytes().toBytesRef().bytes);
+
+        PutPipelineRequest serialized = new PutPipelineRequest();
+        serialized.readFrom(in);
+        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals("{}", serialized.getSource().utf8ToString());
+    }
+
+    public void testSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("ADwDATECe30=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            PutPipelineRequest request = new PutPipelineRequest();
+            request.readFrom(in);
+            assertEquals(XContentType.JSON, request.getXContentType());
+            assertEquals("{}", request.getSource().utf8ToString());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                request.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+}
diff --git a/core/src/test/java/org/elasticsearch/action/ingest/SimulatePipelineRequestTests.java b/core/src/test/java/org/elasticsearch/action/ingest/SimulatePipelineRequestTests.java
index 0966010a8f..86dc56cdd0 100644
--- a/core/src/test/java/org/elasticsearch/action/ingest/SimulatePipelineRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/ingest/SimulatePipelineRequestTests.java
@@ -19,19 +19,23 @@
 
 package org.elasticsearch.action.ingest;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 
 public class SimulatePipelineRequestTests extends ESTestCase {
 
     public void testSerialization() throws IOException {
-        SimulatePipelineRequest request = new SimulatePipelineRequest(new BytesArray(""));
+        SimulatePipelineRequest request = new SimulatePipelineRequest(new BytesArray(""), XContentType.JSON);
         // Sometimes we set an id
         if (randomBoolean()) {
             request.setId(randomAsciiOfLengthBetween(1, 10));
@@ -51,4 +55,38 @@ public class SimulatePipelineRequestTests extends ESTestCase {
         assertThat(otherRequest.getId(), equalTo(request.getId()));
         assertThat(otherRequest.isVerbose(), equalTo(request.isVerbose()));
     }
+
+    public void testSerializationWithXContent() throws IOException {
+        SimulatePipelineRequest request =
+            new SimulatePipelineRequest(new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
+        assertEquals(XContentType.JSON, request.getXContentType());
+
+        BytesStreamOutput output = new BytesStreamOutput();
+        request.writeTo(output);
+        StreamInput in = StreamInput.wrap(output.bytes().toBytesRef().bytes);
+
+        SimulatePipelineRequest serialized = new SimulatePipelineRequest();
+        serialized.readFrom(in);
+        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals("{}", serialized.getSource().utf8ToString());
+    }
+
+    public void testSerializationWithXContentBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("AAAAAnt9AAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            SimulatePipelineRequest request = new SimulatePipelineRequest();
+            request.readFrom(in);
+            assertEquals(XContentType.JSON, request.getXContentType());
+            assertEquals("{}", request.getSource().utf8ToString());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                request.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
 }
diff --git a/core/src/test/java/org/elasticsearch/action/ingest/WriteableIngestDocumentTests.java b/core/src/test/java/org/elasticsearch/action/ingest/WriteableIngestDocumentTests.java
index bc72094558..d5417526c0 100644
--- a/core/src/test/java/org/elasticsearch/action/ingest/WriteableIngestDocumentTests.java
+++ b/core/src/test/java/org/elasticsearch/action/ingest/WriteableIngestDocumentTests.java
@@ -127,7 +127,7 @@ public class WriteableIngestDocumentTests extends ESTestCase {
         builder.startObject();
         writeableIngestDocument.toXContent(builder, EMPTY_PARAMS);
         builder.endObject();
-        Map<String, Object> toXContentMap = XContentHelper.convertToMap(builder.bytes(), false).v2();
+        Map<String, Object> toXContentMap = XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
 
         Map<String, Object> toXContentDoc = (Map<String, Object>) toXContentMap.get("doc");
         Map<String, Object> toXContentSource = (Map<String, Object>) toXContentDoc.get("_source");
diff --git a/core/src/test/java/org/elasticsearch/action/search/MultiSearchRequestTests.java b/core/src/test/java/org/elasticsearch/action/search/MultiSearchRequestTests.java
index d249c33edc..d1de2f7ccf 100644
--- a/core/src/test/java/org/elasticsearch/action/search/MultiSearchRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/search/MultiSearchRequestTests.java
@@ -24,6 +24,7 @@ import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.MatchAllQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryParseContext;
@@ -160,7 +161,8 @@ public class MultiSearchRequestTests extends ESTestCase {
 
     private MultiSearchRequest parseMultiSearchRequest(String sample) throws IOException {
         byte[] data = StreamsUtils.copyToBytesFromClasspath(sample);
-        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data)).build();
+        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry())
+            .withContent(new BytesArray(data), XContentType.JSON).build();
         return RestMultiSearchAction.parseRequest(restRequest, true);
     }
 
diff --git a/core/src/test/java/org/elasticsearch/action/support/WaitActiveShardCountIT.java b/core/src/test/java/org/elasticsearch/action/support/WaitActiveShardCountIT.java
index 2e1a00afc2..cab27d74c7 100644
--- a/core/src/test/java/org/elasticsearch/action/support/WaitActiveShardCountIT.java
+++ b/core/src/test/java/org/elasticsearch/action/support/WaitActiveShardCountIT.java
@@ -25,6 +25,7 @@ import org.elasticsearch.action.admin.indices.create.CreateIndexResponse;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -44,9 +45,9 @@ public class WaitActiveShardCountIT extends ESIntegTestCase {
         assertAcked(createIndexResponse);
 
         // indexing, by default, will work (waiting for one shard copy only)
-        client().prepareIndex("test", "type1", "1").setSource(source("1", "test")).execute().actionGet();
+        client().prepareIndex("test", "type1", "1").setSource(source("1", "test"), XContentType.JSON).execute().actionGet();
         try {
-            client().prepareIndex("test", "type1", "1").setSource(source("1", "test"))
+            client().prepareIndex("test", "type1", "1").setSource(source("1", "test"), XContentType.JSON)
                     .setWaitForActiveShards(2) // wait for 2 active shard copies
                     .setTimeout(timeValueMillis(100)).execute().actionGet();
             fail("can't index, does not enough active shard copies");
@@ -70,12 +71,12 @@ public class WaitActiveShardCountIT extends ESIntegTestCase {
         assertThat(clusterHealth.getStatus(), equalTo(ClusterHealthStatus.YELLOW));
 
         // this should work, since we now have two
-        client().prepareIndex("test", "type1", "1").setSource(source("1", "test"))
+        client().prepareIndex("test", "type1", "1").setSource(source("1", "test"), XContentType.JSON)
                 .setWaitForActiveShards(2)
                 .setTimeout(timeValueSeconds(1)).execute().actionGet();
 
         try {
-            client().prepareIndex("test", "type1", "1").setSource(source("1", "test"))
+            client().prepareIndex("test", "type1", "1").setSource(source("1", "test"), XContentType.JSON)
                     .setWaitForActiveShards(ActiveShardCount.ALL)
                     .setTimeout(timeValueMillis(100)).execute().actionGet();
             fail("can't index, not enough active shard copies");
@@ -92,7 +93,7 @@ public class WaitActiveShardCountIT extends ESIntegTestCase {
         assertThat(clusterHealth.getStatus(), equalTo(ClusterHealthStatus.GREEN));
 
         // this should work, since we now have all shards started
-        client().prepareIndex("test", "type1", "1").setSource(source("1", "test"))
+        client().prepareIndex("test", "type1", "1").setSource(source("1", "test"), XContentType.JSON)
                 .setWaitForActiveShards(ActiveShardCount.ALL)
                 .setTimeout(timeValueSeconds(1)).execute().actionGet();
     }
diff --git a/core/src/test/java/org/elasticsearch/action/termvectors/TermVectorsUnitTests.java b/core/src/test/java/org/elasticsearch/action/termvectors/TermVectorsUnitTests.java
index c255ef6fc8..e034cff3f1 100644
--- a/core/src/test/java/org/elasticsearch/action/termvectors/TermVectorsUnitTests.java
+++ b/core/src/test/java/org/elasticsearch/action/termvectors/TermVectorsUnitTests.java
@@ -36,12 +36,16 @@ import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.termvectors.TermVectorsRequest.Flag;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.InputStreamStreamInput;
 import org.elasticsearch.common.io.stream.OutputStreamStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.index.mapper.AllFieldMapper;
 import org.elasticsearch.index.mapper.FieldMapper;
@@ -56,6 +60,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Base64;
 import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.Set;
@@ -236,6 +241,7 @@ public class TermVectorsUnitTests extends ESTestCase {
             request.parent(parent);
             String pref = random().nextBoolean() ? "somePreference" : null;
             request.preference(pref);
+            request.doc(new BytesArray("{}"), randomBoolean(), XContentType.JSON);
 
             // write
             ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
@@ -255,7 +261,37 @@ public class TermVectorsUnitTests extends ESTestCase {
             assertThat(request.termStatistics(), equalTo(req2.termStatistics()));
             assertThat(request.preference(), equalTo(pref));
             assertThat(request.routing(), equalTo(null));
+            assertEquals(new BytesArray("{}"), request.doc());
+            assertEquals(XContentType.JSON, request.xContentType());
+        }
+    }
 
+    public void testStreamRequestWithXContentBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("AAABBWluZGV4BHR5cGUCaWQBAnt9AAABDnNvbWVQcmVmZXJlbmNlFgAAAAEA//////////0AAAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            TermVectorsRequest request = new TermVectorsRequest();
+            request.readFrom(in);
+            assertEquals("index", request.index());
+            assertEquals("type", request.type());
+            assertEquals("id", request.id());
+            assertTrue(request.offsets());
+            assertFalse(request.fieldStatistics());
+            assertTrue(request.payloads());
+            assertFalse(request.positions());
+            assertTrue(request.termStatistics());
+            assertNull(request.parent());
+            assertEquals("somePreference", request.preference());
+            assertEquals("{}", request.doc().utf8ToString());
+            assertEquals(XContentType.JSON, request.xContentType());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                request.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
         }
     }
 
diff --git a/core/src/test/java/org/elasticsearch/action/update/UpdateRequestTests.java b/core/src/test/java/org/elasticsearch/action/update/UpdateRequestTests.java
index 892401356c..e1133542e4 100644
--- a/core/src/test/java/org/elasticsearch/action/update/UpdateRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/action/update/UpdateRequestTests.java
@@ -144,7 +144,8 @@ public class UpdateRequestTests extends ESTestCase {
         assertThat(params, notNullValue());
         assertThat(params.size(), equalTo(1));
         assertThat(params.get("param1").toString(), equalTo("value1"));
-        Map<String, Object> upsertDoc = XContentHelper.convertToMap(request.upsertRequest().source(), true).v2();
+        Map<String, Object> upsertDoc =
+            XContentHelper.convertToMap(request.upsertRequest().source(), true, request.upsertRequest().getContentType()).v2();
         assertThat(upsertDoc.get("field1").toString(), equalTo("value1"));
         assertThat(((Map) upsertDoc.get("compound")).get("field2").toString(), equalTo("value2"));
 
@@ -171,7 +172,7 @@ public class UpdateRequestTests extends ESTestCase {
         assertThat(params, notNullValue());
         assertThat(params.size(), equalTo(1));
         assertThat(params.get("param1").toString(), equalTo("value1"));
-        upsertDoc = XContentHelper.convertToMap(request.upsertRequest().source(), true).v2();
+        upsertDoc = XContentHelper.convertToMap(request.upsertRequest().source(), true, request.upsertRequest().getContentType()).v2();
         assertThat(upsertDoc.get("field1").toString(), equalTo("value1"));
         assertThat(((Map) upsertDoc.get("compound")).get("field2").toString(), equalTo("value2"));
 
diff --git a/core/src/test/java/org/elasticsearch/aliases/IndexAliasesIT.java b/core/src/test/java/org/elasticsearch/aliases/IndexAliasesIT.java
index 9f04f74cd2..497b134ebe 100644
--- a/core/src/test/java/org/elasticsearch/aliases/IndexAliasesIT.java
+++ b/core/src/test/java/org/elasticsearch/aliases/IndexAliasesIT.java
@@ -35,6 +35,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.StopWatch;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.rest.action.admin.indices.AliasesNotFoundException;
@@ -90,7 +91,8 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().addAlias("test", "alias1"));
 
         logger.info("--> indexing against [alias1], should work now");
-        IndexResponse indexResponse = client().index(indexRequest("alias1").type("type1").id("1").source(source("1", "test"))).actionGet();
+        IndexResponse indexResponse = client().index(indexRequest("alias1").type("type1").id("1")
+            .source(source("1", "test"), XContentType.JSON)).actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test"));
 
         logger.info("--> creating index [test_x]");
@@ -102,7 +104,8 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().removeAlias("test", "alias1").addAlias("test_x", "alias1"));
 
         logger.info("--> indexing against [alias1], should work against [test_x]");
-        indexResponse = client().index(indexRequest("alias1").type("type1").id("1").source(source("1", "test"))).actionGet();
+        indexResponse = client().index(indexRequest("alias1").type("type1").id("1")
+            .source(source("1", "test"), XContentType.JSON)).actionGet();
         assertThat(indexResponse.getIndex(), equalTo("test_x"));
     }
 
@@ -164,15 +167,14 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().addAlias("test", "tests", termQuery("name", "test")));
 
         logger.info("--> indexing against [test]");
-        client().index(indexRequest("test").type("type1").id("1").source(source("1", "foo test")).setRefreshPolicy(RefreshPolicy.IMMEDIATE))
-                .actionGet();
-        client().index(indexRequest("test").type("type1").id("2").source(source("2", "bar test")).setRefreshPolicy(RefreshPolicy.IMMEDIATE))
-                .actionGet();
-        client().index(indexRequest("test").type("type1").id("3").source(source("3", "baz test")).setRefreshPolicy(RefreshPolicy.IMMEDIATE))
-                .actionGet();
-        client().index(
-                indexRequest("test").type("type1").id("4").source(source("4", "something else")).setRefreshPolicy(RefreshPolicy.IMMEDIATE))
-                .actionGet();
+        client().index(indexRequest("test").type("type1").id("1").source(source("1", "foo test"), XContentType.JSON)
+            .setRefreshPolicy(RefreshPolicy.IMMEDIATE)).actionGet();
+        client().index(indexRequest("test").type("type1").id("2").source(source("2", "bar test"), XContentType.JSON)
+            .setRefreshPolicy(RefreshPolicy.IMMEDIATE)).actionGet();
+        client().index(indexRequest("test").type("type1").id("3").source(source("3", "baz test"), XContentType.JSON)
+            .setRefreshPolicy(RefreshPolicy.IMMEDIATE)).actionGet();
+        client().index(indexRequest("test").type("type1").id("4").source(source("4", "something else"), XContentType.JSON)
+                    .setRefreshPolicy(RefreshPolicy.IMMEDIATE)).actionGet();
 
         logger.info("--> checking single filtering alias search");
         SearchResponse searchResponse = client().prepareSearch("foos").setQuery(QueryBuilders.matchAllQuery()).get();
@@ -254,16 +256,16 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().addAlias("test2", "foos", termQuery("name", "foo")));
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").type("type1").id("1").source(source("1", "foo test"))).get();
-        client().index(indexRequest("test1").type("type1").id("2").source(source("2", "bar test"))).get();
-        client().index(indexRequest("test1").type("type1").id("3").source(source("3", "baz test"))).get();
-        client().index(indexRequest("test1").type("type1").id("4").source(source("4", "something else"))).get();
+        client().index(indexRequest("test1").type("type1").id("1").source(source("1", "foo test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("2").source(source("2", "bar test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("3").source(source("3", "baz test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("4").source(source("4", "something else"), XContentType.JSON)).get();
 
         logger.info("--> indexing against [test2]");
-        client().index(indexRequest("test2").type("type1").id("5").source(source("5", "foo test"))).get();
-        client().index(indexRequest("test2").type("type1").id("6").source(source("6", "bar test"))).get();
-        client().index(indexRequest("test2").type("type1").id("7").source(source("7", "baz test"))).get();
-        client().index(indexRequest("test2").type("type1").id("8").source(source("8", "something else"))).get();
+        client().index(indexRequest("test2").type("type1").id("5").source(source("5", "foo test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("6").source(source("6", "bar test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("7").source(source("7", "baz test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("8").source(source("8", "something else"), XContentType.JSON)).get();
 
         refresh();
 
@@ -322,17 +324,17 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().addAlias("test3", "filter13", termQuery("name", "baz")));
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").type("type1").id("11").source(source("11", "foo test1"))).get();
-        client().index(indexRequest("test1").type("type1").id("12").source(source("12", "bar test1"))).get();
-        client().index(indexRequest("test1").type("type1").id("13").source(source("13", "baz test1"))).get();
+        client().index(indexRequest("test1").type("type1").id("11").source(source("11", "foo test1"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("12").source(source("12", "bar test1"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("13").source(source("13", "baz test1"), XContentType.JSON)).get();
 
-        client().index(indexRequest("test2").type("type1").id("21").source(source("21", "foo test2"))).get();
-        client().index(indexRequest("test2").type("type1").id("22").source(source("22", "bar test2"))).get();
-        client().index(indexRequest("test2").type("type1").id("23").source(source("23", "baz test2"))).get();
+        client().index(indexRequest("test2").type("type1").id("21").source(source("21", "foo test2"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("22").source(source("22", "bar test2"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("23").source(source("23", "baz test2"), XContentType.JSON)).get();
 
-        client().index(indexRequest("test3").type("type1").id("31").source(source("31", "foo test3"))).get();
-        client().index(indexRequest("test3").type("type1").id("32").source(source("32", "bar test3"))).get();
-        client().index(indexRequest("test3").type("type1").id("33").source(source("33", "baz test3"))).get();
+        client().index(indexRequest("test3").type("type1").id("31").source(source("31", "foo test3"), XContentType.JSON)).get();
+        client().index(indexRequest("test3").type("type1").id("32").source(source("32", "bar test3"), XContentType.JSON)).get();
+        client().index(indexRequest("test3").type("type1").id("33").source(source("33", "baz test3"), XContentType.JSON)).get();
 
         refresh();
 
@@ -382,16 +384,16 @@ public class IndexAliasesIT extends ESIntegTestCase {
         assertAcked(admin().indices().prepareAliases().addAlias("test2", "tests", termQuery("name", "test")));
 
         logger.info("--> indexing against [test1]");
-        client().index(indexRequest("test1").type("type1").id("1").source(source("1", "foo test"))).get();
-        client().index(indexRequest("test1").type("type1").id("2").source(source("2", "bar test"))).get();
-        client().index(indexRequest("test1").type("type1").id("3").source(source("3", "baz test"))).get();
-        client().index(indexRequest("test1").type("type1").id("4").source(source("4", "something else"))).get();
+        client().index(indexRequest("test1").type("type1").id("1").source(source("1", "foo test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("2").source(source("2", "bar test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("3").source(source("3", "baz test"), XContentType.JSON)).get();
+        client().index(indexRequest("test1").type("type1").id("4").source(source("4", "something else"), XContentType.JSON)).get();
 
         logger.info("--> indexing against [test2]");
-        client().index(indexRequest("test2").type("type1").id("5").source(source("5", "foo test"))).get();
-        client().index(indexRequest("test2").type("type1").id("6").source(source("6", "bar test"))).get();
-        client().index(indexRequest("test2").type("type1").id("7").source(source("7", "baz test"))).get();
-        client().index(indexRequest("test2").type("type1").id("8").source(source("8", "something else"))).get();
+        client().index(indexRequest("test2").type("type1").id("5").source(source("5", "foo test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("6").source(source("6", "bar test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("7").source(source("7", "baz test"), XContentType.JSON)).get();
+        client().index(indexRequest("test2").type("type1").id("8").source(source("8", "something else"), XContentType.JSON)).get();
 
         refresh();
 
@@ -435,7 +437,7 @@ public class IndexAliasesIT extends ESIntegTestCase {
 
         for (int i = 0; i < 10; i++) {
             assertAcked(admin().indices().prepareAliases().addAlias("test", "alias" + i));
-            client().index(indexRequest("alias" + i).type("type1").id("1").source(source("1", "test"))).get();
+            client().index(indexRequest("alias" + i).type("type1").id("1").source(source("1", "test"), XContentType.JSON)).get();
         }
     }
 
@@ -447,7 +449,7 @@ public class IndexAliasesIT extends ESIntegTestCase {
 
         for (int i = 0; i < 10; i++) {
             assertAcked(admin().indices().prepareAliases().addAlias("test", "alias" + i));
-            client().index(indexRequest("alias" + i).type("type1").id("1").source(source("1", "test"))).get();
+            client().index(indexRequest("alias" + i).type("type1").id("1").source(source("1", "test"), XContentType.JSON)).get();
         }
     }
 
@@ -466,7 +468,8 @@ public class IndexAliasesIT extends ESIntegTestCase {
                 @Override
                 public void run() {
                     assertAcked(admin().indices().prepareAliases().addAlias("test", aliasName));
-                    client().index(indexRequest(aliasName).type("type1").id("1").source(source("1", "test"))).actionGet();
+                    client().index(indexRequest(aliasName).type("type1").id("1").source(source("1", "test"), XContentType.JSON))
+                        .actionGet();
                 }
             });
         }
@@ -745,7 +748,7 @@ public class IndexAliasesIT extends ESIntegTestCase {
                 "        \"alias2\" : {\"filter\" : {\"match_all\": {}}},\n" +
                 "        \"alias3\" : { \"index_routing\" : \"index\", \"search_routing\" : \"search\"}\n" +
                 "    }\n" +
-                "}"));
+                "}", XContentType.JSON));
 
         checkAliases();
     }
@@ -826,8 +829,8 @@ public class IndexAliasesIT extends ESIntegTestCase {
                         .addMapping("parent")
                         .addMapping("child", "_parent", "type=parent")
         );
-        client().prepareIndex("my-index", "parent", "1").setSource("{}").get();
-        client().prepareIndex("my-index", "child", "2").setSource("{}").setParent("1").get();
+        client().prepareIndex("my-index", "parent", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("my-index", "child", "2").setSource("{}", XContentType.JSON).setParent("1").get();
         refresh();
 
         assertAcked(admin().indices().prepareAliases().addAlias("my-index", "filter1", hasChildQuery("child", matchAllQuery(), ScoreMode.None)));
diff --git a/core/src/test/java/org/elasticsearch/bwcompat/OldIndexBackwardsCompatibilityIT.java b/core/src/test/java/org/elasticsearch/bwcompat/OldIndexBackwardsCompatibilityIT.java
index 20add0530d..76e9a4eb10 100644
--- a/core/src/test/java/org/elasticsearch/bwcompat/OldIndexBackwardsCompatibilityIT.java
+++ b/core/src/test/java/org/elasticsearch/bwcompat/OldIndexBackwardsCompatibilityIT.java
@@ -35,6 +35,7 @@ import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.routing.RecoverySource;
@@ -388,7 +389,7 @@ public class OldIndexBackwardsCompatibilityIT extends ESIntegTestCase {
         SearchHit hit = searchReq.get().getHits().getAt(0);
         String docId = hit.getId();
         // foo is new, it is not a field in the generated index
-        client().prepareUpdate(indexName, "doc", docId).setDoc("foo", "bar").get();
+        client().prepareUpdate(indexName, "doc", docId).setDoc(Requests.INDEX_CONTENT_TYPE, "foo", "bar").get();
         GetResponse getRsp = client().prepareGet(indexName, "doc", docId).get();
         Map<String, Object> source = getRsp.getSourceAsMap();
         assertThat(source, Matchers.hasKey("foo"));
diff --git a/core/src/test/java/org/elasticsearch/client/AbstractClientHeadersTestCase.java b/core/src/test/java/org/elasticsearch/client/AbstractClientHeadersTestCase.java
index ccc72db9d7..d3a0e0b3e4 100644
--- a/core/src/test/java/org/elasticsearch/client/AbstractClientHeadersTestCase.java
+++ b/core/src/test/java/org/elasticsearch/client/AbstractClientHeadersTestCase.java
@@ -36,6 +36,7 @@ import org.elasticsearch.action.admin.cluster.storedscripts.DeleteStoredScriptAc
 import org.elasticsearch.action.search.SearchAction;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -106,7 +107,7 @@ public abstract class AbstractClientHeadersTestCase extends ESTestCase {
         client.prepareSearch().execute().addListener(new AssertingActionListener<>(SearchAction.NAME, client.threadPool()));
         client.prepareDelete("idx", "type", "id").execute().addListener(new AssertingActionListener<>(DeleteAction.NAME, client.threadPool()));
         client.admin().cluster().prepareDeleteStoredScript("lang", "id").execute().addListener(new AssertingActionListener<>(DeleteStoredScriptAction.NAME, client.threadPool()));
-        client.prepareIndex("idx", "type", "id").setSource("source").execute().addListener(new AssertingActionListener<>(IndexAction.NAME, client.threadPool()));
+        client.prepareIndex("idx", "type", "id").setSource("source", XContentType.JSON).execute().addListener(new AssertingActionListener<>(IndexAction.NAME, client.threadPool()));
 
         // choosing arbitrary cluster admin actions to test
         client.admin().cluster().prepareClusterStats().execute().addListener(new AssertingActionListener<>(ClusterStatsAction.NAME, client.threadPool()));
diff --git a/core/src/test/java/org/elasticsearch/cluster/NoMasterNodeIT.java b/core/src/test/java/org/elasticsearch/cluster/NoMasterNodeIT.java
index 73598c3eff..c799969a3c 100644
--- a/core/src/test/java/org/elasticsearch/cluster/NoMasterNodeIT.java
+++ b/core/src/test/java/org/elasticsearch/cluster/NoMasterNodeIT.java
@@ -24,6 +24,7 @@ import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
 import org.elasticsearch.action.bulk.BulkRequestBuilder;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.settings.Settings;
@@ -236,7 +237,7 @@ public class NoMasterNodeIT extends ESIntegTestCase {
         TimeValue timeout = TimeValue.timeValueMillis(200);
         long now = System.currentTimeMillis();
         try {
-            client().prepareUpdate("test1", "type1", "1").setDoc("field", "value2").setTimeout(timeout).get();
+            client().prepareUpdate("test1", "type1", "1").setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2").setTimeout(timeout).get();
             fail("Expected ClusterBlockException");
         } catch (ClusterBlockException e) {
             assertThat(System.currentTimeMillis() - now, greaterThan(timeout.millis() - 50));
diff --git a/core/src/test/java/org/elasticsearch/cluster/SimpleDataNodesIT.java b/core/src/test/java/org/elasticsearch/cluster/SimpleDataNodesIT.java
index a0a0025681..c2f6c3b64f 100644
--- a/core/src/test/java/org/elasticsearch/cluster/SimpleDataNodesIT.java
+++ b/core/src/test/java/org/elasticsearch/cluster/SimpleDataNodesIT.java
@@ -25,6 +25,7 @@ import org.elasticsearch.action.support.ActiveShardCount;
 import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
@@ -40,7 +41,8 @@ public class SimpleDataNodesIT extends ESIntegTestCase {
         internalCluster().startNode(Settings.builder().put(Node.NODE_DATA_SETTING.getKey(), false).build());
         client().admin().indices().create(createIndexRequest("test").waitForActiveShards(ActiveShardCount.NONE)).actionGet();
         try {
-            client().index(Requests.indexRequest("test").type("type1").id("1").source(source("1", "test")).timeout(timeValueSeconds(1))).actionGet();
+            client().index(Requests.indexRequest("test").type("type1").id("1").source(source("1", "test"), XContentType.JSON)
+                .timeout(timeValueSeconds(1))).actionGet();
             fail("no allocation should happen");
         } catch (UnavailableShardsException e) {
             // all is well
@@ -51,7 +53,8 @@ public class SimpleDataNodesIT extends ESIntegTestCase {
 
         // still no shard should be allocated
         try {
-            client().index(Requests.indexRequest("test").type("type1").id("1").source(source("1", "test")).timeout(timeValueSeconds(1))).actionGet();
+            client().index(Requests.indexRequest("test").type("type1").id("1").source(source("1", "test"), XContentType.JSON)
+                .timeout(timeValueSeconds(1))).actionGet();
             fail("no allocation should happen");
         } catch (UnavailableShardsException e) {
             // all is well
@@ -61,7 +64,8 @@ public class SimpleDataNodesIT extends ESIntegTestCase {
         internalCluster().startNode(Settings.builder().put(Node.NODE_DATA_SETTING.getKey(), true).build());
         assertThat(client().admin().cluster().prepareHealth().setWaitForEvents(Priority.LANGUID).setWaitForNodes("3").setLocal(true).execute().actionGet().isTimedOut(), equalTo(false));
 
-        IndexResponse indexResponse = client().index(Requests.indexRequest("test").type("type1").id("1").source(source("1", "test"))).actionGet();
+        IndexResponse indexResponse = client().index(Requests.indexRequest("test").type("type1").id("1")
+            .source(source("1", "test"), XContentType.JSON)).actionGet();
         assertThat(indexResponse.getId(), equalTo("1"));
         assertThat(indexResponse.getType(), equalTo("type1"));
     }
diff --git a/core/src/test/java/org/elasticsearch/common/settings/SettingsFilterTests.java b/core/src/test/java/org/elasticsearch/common/settings/SettingsFilterTests.java
index 14e93a3bbc..93f745d290 100644
--- a/core/src/test/java/org/elasticsearch/common/settings/SettingsFilterTests.java
+++ b/core/src/test/java/org/elasticsearch/common/settings/SettingsFilterTests.java
@@ -118,7 +118,7 @@ public class SettingsFilterTests extends ESTestCase {
         source.toXContent(xContentBuilder, request);
         xContentBuilder.endObject();
         String filteredSettingsString = xContentBuilder.string();
-        filteredSettings = Settings.builder().loadFromSource(filteredSettingsString).build();
+        filteredSettings = Settings.builder().loadFromSource(filteredSettingsString, xContentBuilder.contentType()).build();
         assertThat(filteredSettings.getAsMap().entrySet(), equalTo(filtered.getAsMap().entrySet()));
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/common/settings/loader/JsonSettingsLoaderTests.java b/core/src/test/java/org/elasticsearch/common/settings/loader/JsonSettingsLoaderTests.java
index d917c0d12c..fc1300d941 100644
--- a/core/src/test/java/org/elasticsearch/common/settings/loader/JsonSettingsLoaderTests.java
+++ b/core/src/test/java/org/elasticsearch/common/settings/loader/JsonSettingsLoaderTests.java
@@ -23,6 +23,7 @@ import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsException;
 import org.elasticsearch.common.xcontent.XContent;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 
 import static org.hamcrest.CoreMatchers.containsString;
@@ -52,7 +53,8 @@ public class JsonSettingsLoaderTests extends ESTestCase {
         assumeFalse("Test only makes sense if XContent parser doesn't have strict duplicate checks enabled",
             XContent.isStrictDuplicateDetectionEnabled());
         final String json = "{\"foo\":\"bar\",\"foo\":\"baz\"}";
-        final SettingsException e = expectThrows(SettingsException.class, () -> Settings.builder().loadFromSource(json).build());
+        final SettingsException e = expectThrows(SettingsException.class,
+            () -> Settings.builder().loadFromSource(json, XContentType.JSON).build());
         assertEquals(e.getCause().getClass(), ElasticsearchParseException.class);
         assertThat(
                 e.toString(),
diff --git a/core/src/test/java/org/elasticsearch/common/settings/loader/YamlSettingsLoaderTests.java b/core/src/test/java/org/elasticsearch/common/settings/loader/YamlSettingsLoaderTests.java
index eeb2df7e1d..e4b4de0ceb 100644
--- a/core/src/test/java/org/elasticsearch/common/settings/loader/YamlSettingsLoaderTests.java
+++ b/core/src/test/java/org/elasticsearch/common/settings/loader/YamlSettingsLoaderTests.java
@@ -23,6 +23,7 @@ import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsException;
 import org.elasticsearch.common.xcontent.XContent;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 
 import java.nio.charset.StandardCharsets;
@@ -74,7 +75,7 @@ public class YamlSettingsLoaderTests extends ESTestCase {
 
         String yaml = "foo: bar\nfoo: baz";
         SettingsException e = expectThrows(SettingsException.class, () -> {
-            Settings.builder().loadFromSource(yaml);
+            Settings.builder().loadFromSource(yaml, XContentType.YAML);
         });
         assertEquals(e.getCause().getClass(), ElasticsearchParseException.class);
         String msg = e.getCause().getMessage();
diff --git a/core/src/test/java/org/elasticsearch/common/xcontent/support/XContentMapValuesTests.java b/core/src/test/java/org/elasticsearch/common/xcontent/support/XContentMapValuesTests.java
index a607b48f79..3a1144afe9 100644
--- a/core/src/test/java/org/elasticsearch/common/xcontent/support/XContentMapValuesTests.java
+++ b/core/src/test/java/org/elasticsearch/common/xcontent/support/XContentMapValuesTests.java
@@ -385,7 +385,7 @@ public class XContentMapValuesTests extends ESTestCase {
                 .endObject()
                 .endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true);
+        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), new String[]{"obj"}, Strings.EMPTY_ARRAY);
 
         assertThat(mapTuple.v2(), equalTo(filteredSource));
@@ -397,7 +397,7 @@ public class XContentMapValuesTests extends ESTestCase {
                 .endObject()
                 .endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true);
+        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), Strings.EMPTY_ARRAY, new String[]{"nonExistingField"});
 
         assertThat(mapTuple.v2(), equalTo(filteredSource));
@@ -410,7 +410,7 @@ public class XContentMapValuesTests extends ESTestCase {
                 .endObject()
                 .endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true);
+        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), Strings.EMPTY_ARRAY, new String[]{"obj.f1"});
 
         assertThat(filteredSource.size(), equalTo(1));
@@ -430,7 +430,7 @@ public class XContentMapValuesTests extends ESTestCase {
                 .endObject();
 
         // implicit include
-        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true);
+        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), Strings.EMPTY_ARRAY, new String[]{"*.obj2"});
 
         assertThat(filteredSource.size(), equalTo(1));
@@ -460,7 +460,7 @@ public class XContentMapValuesTests extends ESTestCase {
                 .endObject()
                 .endObject();
 
-        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true);
+        Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(builder.bytes(), true, builder.contentType());
         Map<String, Object> filteredSource = XContentMapValues.filter(mapTuple.v2(), new String[]{"*.obj2"}, Strings.EMPTY_ARRAY);
 
         assertThat(filteredSource.size(), equalTo(1));
diff --git a/core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsIT.java b/core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsIT.java
index b69b73da3a..5e2869a658 100644
--- a/core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsIT.java
+++ b/core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsIT.java
@@ -48,6 +48,7 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.discovery.zen.FaultDetection;
 import org.elasticsearch.discovery.zen.MembershipAction;
@@ -530,7 +531,7 @@ public class DiscoveryWithServiceDisruptionsIT extends ESIntegTestCase {
                                 int shard = Math.floorMod(Murmur3HashFunction.hash(id), numPrimaries);
                                 logger.trace("[{}] indexing id [{}] through node [{}] targeting shard [{}]", name, id, node, shard);
                                 IndexResponse response =
-                                    client.prepareIndex("test", "type", id).setSource("{}").setTimeout(timeout).get(timeout);
+                                    client.prepareIndex("test", "type", id).setSource("{}", XContentType.JSON).setTimeout(timeout).get(timeout);
                                 assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
                                 ackedDocs.put(id, node);
                                 logger.trace("[{}] indexed id [{}] through node [{}]", name, id, node);
@@ -1122,7 +1123,8 @@ public class DiscoveryWithServiceDisruptionsIT extends ESIntegTestCase {
         final String node_2 = internalCluster().startDataOnlyNode();
         List<IndexRequestBuilder> indexRequestBuilderList = new ArrayList<>();
         for (int i = 0; i < 100; i++) {
-            indexRequestBuilderList.add(client().prepareIndex().setIndex("test").setType("doc").setSource("{\"int_field\":1}"));
+            indexRequestBuilderList.add(client().prepareIndex().setIndex("test").setType("doc")
+                .setSource("{\"int_field\":1}", XContentType.JSON));
         }
         indexRandom(true, indexRequestBuilderList);
         SingleNodeDisruption disruption = new BlockClusterStateProcessing(node_2, random());
diff --git a/core/src/test/java/org/elasticsearch/document/DocumentActionsIT.java b/core/src/test/java/org/elasticsearch/document/DocumentActionsIT.java
index e3556c8cc7..34b4bc0572 100644
--- a/core/src/test/java/org/elasticsearch/document/DocumentActionsIT.java
+++ b/core/src/test/java/org/elasticsearch/document/DocumentActionsIT.java
@@ -32,6 +32,7 @@ import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.hamcrest.ElasticsearchAssertions;
 
@@ -185,7 +186,7 @@ public class DocumentActionsIT extends ESIntegTestCase {
                 .add(client().prepareIndex().setIndex("test").setType("type1").setId("2").setSource(source("2", "test")).setCreate(true))
                 .add(client().prepareIndex().setIndex("test").setType("type1").setSource(source("3", "test")))
                 .add(client().prepareDelete().setIndex("test").setType("type1").setId("1"))
-                .add(client().prepareIndex().setIndex("test").setType("type1").setSource("{ xxx }")) // failure
+                .add(client().prepareIndex().setIndex("test").setType("type1").setSource("{ xxx }", XContentType.JSON)) // failure
                 .execute().actionGet();
 
         assertThat(bulkResponse.hasFailures(), equalTo(true));
diff --git a/core/src/test/java/org/elasticsearch/document/ShardInfoIT.java b/core/src/test/java/org/elasticsearch/document/ShardInfoIT.java
index 814a861139..84166bb3f9 100644
--- a/core/src/test/java/org/elasticsearch/document/ShardInfoIT.java
+++ b/core/src/test/java/org/elasticsearch/document/ShardInfoIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.action.update.UpdateResponse;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
@@ -45,7 +46,7 @@ public class ShardInfoIT extends ESIntegTestCase {
 
     public void testIndexAndDelete() throws Exception {
         prepareIndex(1);
-        IndexResponse indexResponse = client().prepareIndex("idx", "type").setSource("{}").get();
+        IndexResponse indexResponse = client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON).get();
         assertShardInfo(indexResponse);
         DeleteResponse deleteResponse = client().prepareDelete("idx", "type", indexResponse.getId()).get();
         assertShardInfo(deleteResponse);
@@ -53,7 +54,8 @@ public class ShardInfoIT extends ESIntegTestCase {
 
     public void testUpdate() throws Exception {
         prepareIndex(1);
-        UpdateResponse updateResponse = client().prepareUpdate("idx", "type", "1").setDoc("{}").setDocAsUpsert(true).get();
+        UpdateResponse updateResponse = client().prepareUpdate("idx", "type", "1").setDoc("{}", XContentType.JSON).setDocAsUpsert(true)
+            .get();
         assertShardInfo(updateResponse);
     }
 
@@ -61,7 +63,7 @@ public class ShardInfoIT extends ESIntegTestCase {
         prepareIndex(1);
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
         for (int i = 0; i < 10; i++) {
-            bulkRequestBuilder.add(client().prepareIndex("idx", "type").setSource("{}"));
+            bulkRequestBuilder.add(client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
         }
 
         BulkResponse bulkResponse = bulkRequestBuilder.get();
@@ -83,7 +85,8 @@ public class ShardInfoIT extends ESIntegTestCase {
         prepareIndex(1);
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
         for (int i = 0; i < 10; i++) {
-            bulkRequestBuilder.add(client().prepareUpdate("idx", "type", Integer.toString(i)).setDoc("{}").setDocAsUpsert(true));
+            bulkRequestBuilder.add(client().prepareUpdate("idx", "type", Integer.toString(i)).setDoc("{}", XContentType.JSON)
+                .setDocAsUpsert(true));
         }
 
         BulkResponse bulkResponse = bulkRequestBuilder.get();
diff --git a/core/src/test/java/org/elasticsearch/get/GetActionIT.java b/core/src/test/java/org/elasticsearch/get/GetActionIT.java
index f6164d2f34..577087ba95 100644
--- a/core/src/test/java/org/elasticsearch/get/GetActionIT.java
+++ b/core/src/test/java/org/elasticsearch/get/GetActionIT.java
@@ -37,6 +37,7 @@ import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.engine.VersionConflictEngineException;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -629,8 +630,8 @@ public class GetActionIT extends ESIntegTestCase {
 
         logger.info("indexing documents");
 
-        client().prepareIndex("my-index", "my-type1", "1").setSource(source).get();
-        client().prepareIndex("my-index", "my-type2", "1").setSource(source).get();
+        client().prepareIndex("my-index", "my-type1", "1").setSource(source, XContentType.JSON).get();
+        client().prepareIndex("my-index", "my-type2", "1").setSource(source, XContentType.JSON).get();
 
         logger.info("checking real time retrieval");
 
@@ -698,7 +699,7 @@ public class GetActionIT extends ESIntegTestCase {
                 "    }\n" +
                 "  }\n" +
                 "}";
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
         String doc = "{\n" +
                 "  \"suggest\": {\n" +
@@ -737,10 +738,10 @@ public class GetActionIT extends ESIntegTestCase {
                 "    }\n" +
                 "  }\n" +
                 "}";
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
 
-        client().prepareIndex("test", "doc").setId("1").setSource("{}").setParent("1").get();
+        client().prepareIndex("test", "doc").setId("1").setSource("{}", XContentType.JSON).setParent("1").get();
 
         String[] fieldsList = {"_parent"};
         // before refresh - document is only in translog
@@ -761,12 +762,12 @@ public class GetActionIT extends ESIntegTestCase {
             "  }\n" +
             "}";
 
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
         String doc = "{\n" +
             "  \"text\": \"some text.\"\n" +
             "}\n";
-        client().prepareIndex("test", "doc").setId("1").setSource(doc).setRouting("1").get();
+        client().prepareIndex("test", "doc").setId("1").setSource(doc, XContentType.JSON).setRouting("1").get();
         String[] fieldsList = {"_routing"};
         // before refresh - document is only in translog
         assertGetFieldsAlwaysWorks(indexOrAlias(), "doc", "1", fieldsList, "1");
@@ -828,7 +829,7 @@ public class GetActionIT extends ESIntegTestCase {
                 "  }\n" +
                 "}";
 
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
         String doc = "{\n" +
                 "  \"text1\": \"some text.\"\n," +
@@ -890,7 +891,7 @@ public class GetActionIT extends ESIntegTestCase {
                 "  }\n" +
                 "}";
 
-        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource));
+        assertAcked(prepareCreate("test").addAlias(new Alias("alias")).setSource(createIndexSource, XContentType.JSON));
         ensureGreen();
         String doc = "{\n" +
                 "  \"token_count\": \"A text with five words.\",\n" +
diff --git a/core/src/test/java/org/elasticsearch/index/IndexRequestBuilderIT.java b/core/src/test/java/org/elasticsearch/index/IndexRequestBuilderIT.java
index 84a9fe2970..7fa769b261 100644
--- a/core/src/test/java/org/elasticsearch/index/IndexRequestBuilderIT.java
+++ b/core/src/test/java/org/elasticsearch/index/IndexRequestBuilderIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.hamcrest.ElasticsearchAssertions;
@@ -40,10 +41,11 @@ public class IndexRequestBuilderIT extends ESIntegTestCase {
         map.put("test_field", "foobar");
         IndexRequestBuilder[] builders = new IndexRequestBuilder[] {
                 client().prepareIndex("test", "test").setSource((Object)"test_field", (Object)"foobar"),
-                client().prepareIndex("test", "test").setSource("{\"test_field\" : \"foobar\"}"),
-                client().prepareIndex("test", "test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}")),
-                client().prepareIndex("test", "test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}")),
-                client().prepareIndex("test", "test").setSource(BytesReference.toBytes(new BytesArray("{\"test_field\" : \"foobar\"}"))),
+                client().prepareIndex("test", "test").setSource("{\"test_field\" : \"foobar\"}", XContentType.JSON),
+                client().prepareIndex("test", "test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), XContentType.JSON),
+                client().prepareIndex("test", "test").setSource(new BytesArray("{\"test_field\" : \"foobar\"}"), XContentType.JSON),
+                client().prepareIndex("test", "test")
+                    .setSource(BytesReference.toBytes(new BytesArray("{\"test_field\" : \"foobar\"}")), XContentType.JSON),
                 client().prepareIndex("test", "test").setSource(map)
         };
         indexRandom(true, builders);
diff --git a/core/src/test/java/org/elasticsearch/index/IndexServiceTests.java b/core/src/test/java/org/elasticsearch/index/IndexServiceTests.java
index 28d67a4a1e..80e453d665 100644
--- a/core/src/test/java/org/elasticsearch/index/IndexServiceTests.java
+++ b/core/src/test/java/org/elasticsearch/index/IndexServiceTests.java
@@ -29,6 +29,7 @@ import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.shard.IndexShard;
@@ -232,7 +233,7 @@ public class IndexServiceTests extends ESSingleNodeTestCase {
         // now disable
         IndexMetaData metaData = IndexMetaData.builder(indexService.getMetaData()).settings(Settings.builder().put(indexService.getMetaData().getSettings()).put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), -1)).build();
         indexService.updateMetaData(metaData);
-        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}").get();
+        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
         IndexShard shard = indexService.getShard(0);
         try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
             TopDocs search = searcher.searcher().search(new MatchAllDocsQuery(), 10);
@@ -259,7 +260,7 @@ public class IndexServiceTests extends ESSingleNodeTestCase {
         IndexService indexService = createIndex("test", settings);
         ensureGreen("test");
         assertTrue(indexService.getRefreshTask().mustReschedule());
-        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}").get();
+        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
         IndexShard shard = indexService.getShard(0);
         assertBusy(() -> {
             assertFalse(shard.getTranslog().syncNeeded());
@@ -278,7 +279,7 @@ public class IndexServiceTests extends ESSingleNodeTestCase {
         indexService.updateMetaData(metaData);
         assertNotNull(indexService.getFsyncTask());
         assertTrue(indexService.getRefreshTask().mustReschedule());
-        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}").get();
+        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
         IndexShard shard = indexService.getShard(0);
         assertBusy(() -> {
             assertFalse(shard.getTranslog().syncNeeded());
diff --git a/core/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java b/core/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
index ecdba6ec44..c815b2b55f 100644
--- a/core/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
+++ b/core/src/test/java/org/elasticsearch/index/IndexingSlowLogTests.java
@@ -25,6 +25,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.index.IndexingSlowLog.SlowLogParsedDocumentPrinter;
 import org.elasticsearch.index.mapper.ParsedDocument;
@@ -41,7 +42,7 @@ public class IndexingSlowLogTests extends ESTestCase {
     public void testSlowLogParsedDocumentPrinterSourceToLog() throws IOException {
         BytesReference source = JsonXContent.contentBuilder().startObject().field("foo", "bar").endObject().bytes();
         ParsedDocument pd = new ParsedDocument(new NumericDocValuesField("version", 1), SeqNoFieldMapper.SequenceID.emptySeqID(), "id",
-                "test", null, null, source, null);
+                "test", null, null, source, XContentType.JSON, null);
         Index index = new Index("foo", "123");
         // Turning off document logging doesn't log source[]
         SlowLogParsedDocumentPrinter p = new SlowLogParsedDocumentPrinter(index, pd, 10, true, 0);
diff --git a/core/src/test/java/org/elasticsearch/index/WaitUntilRefreshIT.java b/core/src/test/java/org/elasticsearch/index/WaitUntilRefreshIT.java
index 0f72e72f6a..ca089e6eb8 100644
--- a/core/src/test/java/org/elasticsearch/index/WaitUntilRefreshIT.java
+++ b/core/src/test/java/org/elasticsearch/index/WaitUntilRefreshIT.java
@@ -28,6 +28,7 @@ import org.elasticsearch.action.delete.DeleteResponse;
 import org.elasticsearch.action.index.IndexResponse;
 import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
 import org.elasticsearch.action.update.UpdateResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.plugins.ScriptPlugin;
@@ -95,14 +96,15 @@ public class WaitUntilRefreshIT extends ESIntegTestCase {
         assertSearchHits(client().prepareSearch("test").setQuery(matchQuery("foo", "bar")).get(), "1");
 
         // Update with RefreshPolicy.WAIT_UNTIL
-        UpdateResponse update = client().prepareUpdate("test", "test", "1").setDoc("foo", "baz").setRefreshPolicy(RefreshPolicy.WAIT_UNTIL)
+        UpdateResponse update = client().prepareUpdate("test", "test", "1")
+            .setDoc(Requests.INDEX_CONTENT_TYPE, "foo", "baz").setRefreshPolicy(RefreshPolicy.WAIT_UNTIL)
                 .get();
         assertEquals(2, update.getVersion());
         assertFalse("request shouldn't have forced a refresh", update.forcedRefresh());
         assertSearchHits(client().prepareSearch("test").setQuery(matchQuery("foo", "baz")).get(), "1");
 
         // Upsert with RefreshPolicy.WAIT_UNTIL
-        update = client().prepareUpdate("test", "test", "2").setDocAsUpsert(true).setDoc("foo", "cat")
+        update = client().prepareUpdate("test", "test", "2").setDocAsUpsert(true).setDoc(Requests.INDEX_CONTENT_TYPE, "foo", "cat")
                 .setRefreshPolicy(RefreshPolicy.WAIT_UNTIL).get();
         assertEquals(1, update.getVersion());
         assertFalse("request shouldn't have forced a refresh", update.forcedRefresh());
@@ -125,7 +127,7 @@ public class WaitUntilRefreshIT extends ESIntegTestCase {
 
         // Update by bulk with RefreshPolicy.WAIT_UNTIL
         bulk = client().prepareBulk().setRefreshPolicy(RefreshPolicy.WAIT_UNTIL);
-        bulk.add(client().prepareUpdate("test", "test", "1").setDoc("foo", "baz"));
+        bulk.add(client().prepareUpdate("test", "test", "1").setDoc(Requests.INDEX_CONTENT_TYPE, "foo", "baz"));
         assertBulkSuccess(bulk.get());
         assertSearchHits(client().prepareSearch("test").setQuery(matchQuery("foo", "baz")).get(), "1");
 
diff --git a/core/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java b/core/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
index 7c586b204b..94b95d1aab 100644
--- a/core/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
+++ b/core/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java
@@ -88,6 +88,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.VersionType;
@@ -290,7 +291,8 @@ public class InternalEngineTests extends ESTestCase {
         document.add(seqID.seqNo);
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
-        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, mappingUpdate);
+        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, XContentType.JSON,
+            mappingUpdate);
     }
 
     protected Store createStore() throws IOException {
@@ -718,7 +720,7 @@ public class InternalEngineTests extends ESTestCase {
 
     public void testFlushIsDisabledDuringTranslogRecovery() throws IOException {
         assertFalse(engine.isRecovering());
-        ParsedDocument doc = testParsedDocument("1", "test", null, testDocumentWithTextField(), B_1, null);
+        ParsedDocument doc = testParsedDocument("1", "test", null, testDocumentWithTextField(), SOURCE, null);
         engine.index(indexForDoc(doc));
         engine.close();
 
@@ -727,7 +729,7 @@ public class InternalEngineTests extends ESTestCase {
         assertTrue(engine.isRecovering());
         engine.recoverFromTranslog();
         assertFalse(engine.isRecovering());
-        doc = testParsedDocument("2", "test", null, testDocumentWithTextField(), B_1, null);
+        doc = testParsedDocument("2", "test", null, testDocumentWithTextField(), SOURCE, null);
         engine.index(indexForDoc(doc));
         engine.flush();
     }
diff --git a/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java b/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
index 219af4af4d..53708b28df 100644
--- a/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
+++ b/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
@@ -48,6 +48,7 @@ import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.BigArrays;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.codec.CodecService;
 import org.elasticsearch.index.mapper.Mapping;
@@ -179,7 +180,8 @@ public class ShadowEngineTests extends ESTestCase {
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
         document.add(new LongPoint("point_field", 42)); // so that points report memory/disk usage
-        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, mappingsUpdate);
+        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, XContentType.JSON,
+            mappingsUpdate);
     }
 
     protected Store createStore(Path p) throws IOException {
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingDisabledTests.java b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingDisabledTests.java
index 346b441470..46749e792e 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingDisabledTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingDisabledTests.java
@@ -28,6 +28,7 @@ import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.AutoCreateIndex;
 import org.elasticsearch.action.update.UpdateHelper;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.action.shard.ShardStateAction;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.service.ClusterService;
@@ -110,7 +111,7 @@ public class DynamicMappingDisabledTests extends ESSingleNodeTestCase {
 
     public void testDynamicDisabled() {
         IndexRequest request = new IndexRequest("index", "type", "1");
-        request.source("foo", 3);
+        request.source(Requests.INDEX_CONTENT_TYPE, "foo", 3);
         BulkRequest bulkRequest = new BulkRequest();
         bulkRequest.add(request);
         final AtomicBoolean onFailureCalled = new AtomicBoolean();
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
index f5c8d38503..41256113cd 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
@@ -197,7 +197,7 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
 
     private Mapper parse(DocumentMapper mapper, DocumentMapperParser parser, XContentBuilder builder) throws Exception {
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT).build();
-        SourceToParse source = SourceToParse.source("test", mapper.type(), "some_id", builder.bytes());
+        SourceToParse source = SourceToParse.source("test", mapper.type(), "some_id", builder.bytes(), builder.contentType());
         try (XContentParser xContentParser = createParser(JsonXContent.jsonXContent, source.source())) {
             ParseContext.InternalParseContext ctx = new ParseContext.InternalParseContext(settings, parser, mapper, source, xContentParser);
             assertEquals(XContentParser.Token.START_OBJECT, ctx.parser().nextToken());
@@ -550,7 +550,7 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
         XContentBuilder json = XContentFactory.jsonBuilder().startObject()
                     .field("field", "foo")
                 .endObject();
-        SourceToParse source = SourceToParse.source("test", "type1", "1", json.bytes());
+        SourceToParse source = SourceToParse.source("test", "type1", "1", json.bytes(), json.contentType());
         DocumentMapper mapper = indexService.mapperService().documentMapper("type1");
         assertNull(mapper.mappers().getMapper("field.raw"));
         ParsedDocument parsed = mapper.parse(source);
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/IdFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/IdFieldMapperTests.java
index 55b6e7bf71..b7ad6a7e4c 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/IdFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/IdFieldMapperTests.java
@@ -21,6 +21,7 @@ package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.IdFieldMapper;
 import org.elasticsearch.index.mapper.MapperParsingException;
@@ -33,7 +34,7 @@ import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 
 public class IdFieldMapperTests extends ESSingleNodeTestCase {
-    
+
     public void testId() throws Exception {
         String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
                 .endObject().endObject().string();
@@ -54,7 +55,7 @@ public class IdFieldMapperTests extends ESSingleNodeTestCase {
 
         try {
             docMapper.parse(SourceToParse.source("test", "type", "1", XContentFactory.jsonBuilder()
-                .startObject().field("_id", "1").endObject().bytes()));
+                .startObject().field("_id", "1").endObject().bytes(), XContentType.JSON));
             fail("Expected failure to parse metadata field");
         } catch (MapperParsingException e) {
             assertTrue(e.getMessage(), e.getMessage().contains("Field [_id] is a metadata field and cannot be added inside a document"));
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java b/core/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java
index 3c9a1c16d1..5543baff1a 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/MapperServiceTests.java
@@ -20,9 +20,11 @@
 package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.ExceptionsHelper;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.KeywordFieldMapper.KeywordFieldType;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
@@ -91,7 +93,7 @@ public class MapperServiceTests extends ESSingleNodeTestCase {
     public void testIndexIntoDefaultMapping() throws Throwable {
         // 1. test implicit index creation
         ExecutionException e = expectThrows(ExecutionException.class, () -> {
-            client().prepareIndex("index1", MapperService.DEFAULT_MAPPING, "1").setSource("{}").execute().get();
+            client().prepareIndex("index1", MapperService.DEFAULT_MAPPING, "1").setSource("{}", XContentType.JSON).execute().get();
         });
         Throwable throwable = ExceptionsHelper.unwrapCause(e.getCause());
         if (throwable instanceof IllegalArgumentException) {
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/MultiFieldTests.java b/core/src/test/java/org/elasticsearch/index/mapper/MultiFieldTests.java
index 5c70465d77..8f17b3e0e0 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/MultiFieldTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/MultiFieldTests.java
@@ -186,7 +186,8 @@ public class MultiFieldTests extends ESSingleNodeTestCase {
         DocumentMapper docMapper = createIndex("test").mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
         Arrays.sort(multiFieldNames);
 
-        Map<String, Object> sourceAsMap = XContentHelper.convertToMap(docMapper.mappingSource().compressedReference(), true).v2();
+        Map<String, Object> sourceAsMap =
+            XContentHelper.convertToMap(docMapper.mappingSource().compressedReference(), true, builder.contentType()).v2();
         @SuppressWarnings("unchecked")
         Map<String, Object> multiFields = (Map<String, Object>) XContentMapValues.extractValue("type.properties.my_field.fields", sourceAsMap);
         assertThat(multiFields.size(), equalTo(multiFieldNames.length));
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
index 225940d8ed..af5061e62a 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
@@ -25,6 +25,7 @@ import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.IndexSettings;
@@ -53,7 +54,7 @@ public class ParentFieldMapperTests extends ESSingleNodeTestCase {
 
         try {
             docMapper.parse(SourceToParse.source("test", "type", "1", XContentFactory.jsonBuilder()
-                .startObject().field("_parent", "1122").endObject().bytes()));
+                .startObject().field("_parent", "1122").endObject().bytes(), XContentType.JSON));
             fail("Expected failure to parse metadata field");
         } catch (MapperParsingException e) {
             assertTrue(e.getMessage(), e.getMessage().contains("Field [_parent] is a metadata field and cannot be added inside a document"));
@@ -72,13 +73,14 @@ public class ParentFieldMapperTests extends ESSingleNodeTestCase {
 
         // Indexing parent doc:
         DocumentMapper parentDocMapper = indexService.mapperService().documentMapper("parent_type");
-        ParsedDocument doc = parentDocMapper.parse(SourceToParse.source("test", "parent_type", "1122", new BytesArray("{}")));
+        ParsedDocument doc =
+            parentDocMapper.parse(SourceToParse.source("test", "parent_type", "1122", new BytesArray("{}"), XContentType.JSON));
         assertEquals(1, getNumberOfFieldWithParentPrefix(doc.rootDoc()));
         assertEquals("1122", doc.rootDoc().getBinaryValue("_parent#parent_type").utf8ToString());
 
         // Indexing child doc:
         DocumentMapper childDocMapper = indexService.mapperService().documentMapper("child_type");
-        doc = childDocMapper.parse(SourceToParse.source("test", "child_type", "1", new BytesArray("{}")).parent("1122"));
+        doc = childDocMapper.parse(SourceToParse.source("test", "child_type", "1", new BytesArray("{}"), XContentType.JSON).parent("1122"));
 
         assertEquals(1, getNumberOfFieldWithParentPrefix(doc.rootDoc()));
         assertEquals("1122", doc.rootDoc().getBinaryValue("_parent#parent_type").utf8ToString());
@@ -92,7 +94,7 @@ public class ParentFieldMapperTests extends ESSingleNodeTestCase {
                 .startObject()
                 .field("x_field", "x_value")
                 .endObject()
-                .bytes()));
+                .bytes(), XContentType.JSON));
         assertEquals(0, getNumberOfFieldWithParentPrefix(doc.rootDoc()));
     }
 
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/RoutingFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/RoutingFieldMapperTests.java
index 92e93ede9a..9c26a9806e 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/RoutingFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/RoutingFieldMapperTests.java
@@ -21,6 +21,7 @@ package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.index.mapper.ParsedDocument;
@@ -40,7 +41,7 @@ public class RoutingFieldMapperTests extends ESSingleNodeTestCase {
             .startObject()
             .field("field", "value")
             .endObject()
-            .bytes()).routing("routing_value"));
+            .bytes(), XContentType.JSON).routing("routing_value"));
 
         assertThat(doc.rootDoc().get("_routing"), equalTo("routing_value"));
         assertThat(doc.rootDoc().get("field"), equalTo("value"));
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/SourceFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/SourceFieldMapperTests.java
index adf05b9b33..5803d7d957 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/SourceFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/SourceFieldMapperTests.java
@@ -144,7 +144,8 @@ public class SourceFieldMapperTests extends ESSingleNodeTestCase {
                 .startObject("_source").field("enabled", true).endObject()
                 .endObject().endObject().string();
 
-        DocumentMapper mapper = createIndex("test").mapperService().documentMapperParser().parse("my_type", new CompressedXContent(mapping), defaultMapping);
+        DocumentMapper mapper = createIndex("test").mapperService().documentMapperParser()
+            .parse("my_type", new CompressedXContent(mapping), defaultMapping);
         assertThat(mapper.type(), equalTo("my_type"));
         assertThat(mapper.sourceMapper().enabled(), equalTo(true));
     }
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingOnClusterIT.java b/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingOnClusterIT.java
index ed0822d4d5..67d7873b7b 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingOnClusterIT.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingOnClusterIT.java
@@ -21,20 +21,16 @@ package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.indices.mapping.get.GetMappingsResponse;
-import org.elasticsearch.action.admin.indices.mapping.put.PutMappingResponse;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.InternalSettingsPlugin;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashMap;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.elasticsearch.test.StreamsUtils.copyToStringFromClasspath;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
diff --git a/core/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java b/core/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java
index 8daf45ed0d..ee1265eca6 100644
--- a/core/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java
+++ b/core/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java
@@ -26,17 +26,20 @@ import org.apache.lucene.index.memory.MemoryIndex;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Query;
 import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.termvectors.MultiTermVectorsItemResponse;
 import org.elasticsearch.action.termvectors.MultiTermVectorsRequest;
 import org.elasticsearch.action.termvectors.MultiTermVectorsResponse;
 import org.elasticsearch.action.termvectors.TermVectorsRequest;
 import org.elasticsearch.action.termvectors.TermVectorsResponse;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.lucene.search.MoreLikeThisQuery;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.query.MoreLikeThisQueryBuilder.Item;
@@ -46,6 +49,7 @@ import org.junit.Before;
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Base64;
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashMap;
@@ -301,6 +305,26 @@ public class MoreLikeThisQueryBuilderTests extends AbstractQueryTestCase<MoreLik
         assertEquals(expectedItem, newItem);
     }
 
+    public void testItemSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("AQVpbmRleAEEdHlwZQEODXsiZm9vIjoiYmFyIn0A/wD//////////QAAAAAAAAAA");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            Item item = new Item(in);
+            assertEquals(XContentType.JSON, item.xContentType());
+            assertEquals("{\"foo\":\"bar\"}", item.doc().utf8ToString());
+            assertEquals("index", item.index());
+            assertEquals("type", item.type());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                item.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+
     @Override
     protected boolean isCachable(MoreLikeThisQueryBuilder queryBuilder) {
         return queryBuilder.likeItems().length == 0; // items are always fetched
diff --git a/core/src/test/java/org/elasticsearch/index/replication/ESIndexLevelReplicationTestCase.java b/core/src/test/java/org/elasticsearch/index/replication/ESIndexLevelReplicationTestCase.java
index ede687d633..863c76bb76 100644
--- a/core/src/test/java/org/elasticsearch/index/replication/ESIndexLevelReplicationTestCase.java
+++ b/core/src/test/java/org/elasticsearch/index/replication/ESIndexLevelReplicationTestCase.java
@@ -42,6 +42,7 @@ import org.elasticsearch.cluster.routing.ShardRoutingState;
 import org.elasticsearch.cluster.routing.TestShardRouting;
 import org.elasticsearch.common.collect.Iterators;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.mapper.Uid;
@@ -120,7 +121,7 @@ public abstract class ESIndexLevelReplicationTestCase extends IndexShardTestCase
         public int indexDocs(final int numOfDoc) throws Exception {
             for (int doc = 0; doc < numOfDoc; doc++) {
                 final IndexRequest indexRequest = new IndexRequest(index.getName(), "type", Integer.toString(docId.incrementAndGet()))
-                    .source("{}");
+                    .source("{}", XContentType.JSON);
                 final IndexResponse response = index(indexRequest);
                 assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
             }
@@ -130,7 +131,7 @@ public abstract class ESIndexLevelReplicationTestCase extends IndexShardTestCase
 
         public int appendDocs(final int numOfDoc) throws Exception {
             for (int doc = 0; doc < numOfDoc; doc++) {
-                final IndexRequest indexRequest = new IndexRequest(index.getName(), "type").source("{}");
+                final IndexRequest indexRequest = new IndexRequest(index.getName(), "type").source("{}", XContentType.JSON);
                 final IndexResponse response = index(indexRequest);
                 assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
             }
diff --git a/core/src/test/java/org/elasticsearch/index/replication/IndexLevelReplicationTests.java b/core/src/test/java/org/elasticsearch/index/replication/IndexLevelReplicationTests.java
index 41edc303f9..39d8778c2a 100644
--- a/core/src/test/java/org/elasticsearch/index/replication/IndexLevelReplicationTests.java
+++ b/core/src/test/java/org/elasticsearch/index/replication/IndexLevelReplicationTests.java
@@ -24,6 +24,7 @@ import org.elasticsearch.action.index.IndexResponse;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.engine.InternalEngine;
 import org.elasticsearch.index.engine.InternalEngineTests;
@@ -110,7 +111,7 @@ public class IndexLevelReplicationTests extends ESIndexLevelReplicationTestCase
     public void testInheritMaxValidAutoIDTimestampOnRecovery() throws Exception {
         try (ReplicationGroup shards = createGroup(0)) {
             shards.startAll();
-            final IndexRequest indexRequest = new IndexRequest(index.getName(), "type").source("{}");
+            final IndexRequest indexRequest = new IndexRequest(index.getName(), "type").source("{}", XContentType.JSON);
             indexRequest.onRetry(); // force an update of the timestamp
             final IndexResponse response = shards.index(indexRequest);
             assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
diff --git a/core/src/test/java/org/elasticsearch/index/shard/IndexShardIT.java b/core/src/test/java/org/elasticsearch/index/shard/IndexShardIT.java
index 3e35ed357f..97c96c8af1 100644
--- a/core/src/test/java/org/elasticsearch/index/shard/IndexShardIT.java
+++ b/core/src/test/java/org/elasticsearch/index/shard/IndexShardIT.java
@@ -44,6 +44,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.env.ShardLock;
@@ -102,7 +103,8 @@ public class IndexShardIT extends ESSingleNodeTestCase {
     }
 
     private ParsedDocument testParsedDocument(String id, String type, String routing, long seqNo,
-                                              ParseContext.Document document, BytesReference source, Mapping mappingUpdate) {
+                                              ParseContext.Document document, BytesReference source, XContentType xContentType,
+                                              Mapping mappingUpdate) {
         Field uidField = new Field("_uid", Uid.createUid(type, id), UidFieldMapper.Defaults.FIELD_TYPE);
         Field versionField = new NumericDocValuesField("_version", 0);
         SeqNoFieldMapper.SequenceID seqID = SeqNoFieldMapper.SequenceID.emptySeqID();
@@ -112,7 +114,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
         return new ParsedDocument(versionField, seqID, id, type, routing,
-                Collections.singletonList(document), source, mappingUpdate);
+                Collections.singletonList(document), source, xContentType, mappingUpdate);
     }
 
     public void testLockTryingToDelete() throws Exception {
@@ -146,7 +148,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
     public void testMarkAsInactiveTriggersSyncedFlush() throws Exception {
         assertAcked(client().admin().indices().prepareCreate("test")
             .setSettings(SETTING_NUMBER_OF_SHARDS, 1, SETTING_NUMBER_OF_REPLICAS, 0));
-        client().prepareIndex("test", "test").setSource("{}").get();
+        client().prepareIndex("test", "test").setSource("{}", XContentType.JSON).get();
         ensureGreen("test");
         IndicesService indicesService = getInstanceFromNode(IndicesService.class);
         indicesService.indexService(resolveIndex("test")).getShardOrNull(0).checkIdle(0);
@@ -163,14 +165,14 @@ public class IndexShardIT extends ESSingleNodeTestCase {
     public void testDurableFlagHasEffect() {
         createIndex("test");
         ensureGreen();
-        client().prepareIndex("test", "bar", "1").setSource("{}").get();
+        client().prepareIndex("test", "bar", "1").setSource("{}", XContentType.JSON).get();
         IndicesService indicesService = getInstanceFromNode(IndicesService.class);
         IndexService test = indicesService.indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
         setDurability(shard, Translog.Durability.REQUEST);
         assertFalse(ShardUtilsTests.getShardEngine(shard).getTranslog().syncNeeded());
         setDurability(shard, Translog.Durability.ASYNC);
-        client().prepareIndex("test", "bar", "2").setSource("{}").get();
+        client().prepareIndex("test", "bar", "2").setSource("{}", XContentType.JSON).get();
         assertTrue(ShardUtilsTests.getShardEngine(shard).getTranslog().syncNeeded());
         setDurability(shard, Translog.Durability.REQUEST);
         client().prepareDelete("test", "bar", "1").get();
@@ -181,13 +183,13 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         assertTrue(ShardUtilsTests.getShardEngine(shard).getTranslog().syncNeeded());
         setDurability(shard, Translog.Durability.REQUEST);
         assertNoFailures(client().prepareBulk()
-            .add(client().prepareIndex("test", "bar", "3").setSource("{}"))
+            .add(client().prepareIndex("test", "bar", "3").setSource("{}", XContentType.JSON))
             .add(client().prepareDelete("test", "bar", "1")).get());
         assertFalse(ShardUtilsTests.getShardEngine(shard).getTranslog().syncNeeded());
 
         setDurability(shard, Translog.Durability.ASYNC);
         assertNoFailures(client().prepareBulk()
-            .add(client().prepareIndex("test", "bar", "4").setSource("{}"))
+            .add(client().prepareIndex("test", "bar", "4").setSource("{}", XContentType.JSON))
             .add(client().prepareDelete("test", "bar", "3")).get());
         setDurability(shard, Translog.Durability.REQUEST);
         assertTrue(ShardUtilsTests.getShardEngine(shard).getTranslog().syncNeeded());
@@ -218,7 +220,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
             .build();
         createIndex("test", idxSettings);
         ensureGreen("test");
-        client().prepareIndex("test", "bar", "1").setSource("{}").setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("test", "bar", "1").setSource("{}", XContentType.JSON).setRefreshPolicy(IMMEDIATE).get();
         SearchResponse response = client().prepareSearch("test").get();
         assertHitCount(response, 1L);
         client().admin().indices().prepareDelete("test").get();
@@ -230,7 +232,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         assertAcked(client().admin().indices().prepareCreate("test")
             .setSettings(SETTING_NUMBER_OF_SHARDS, 1, SETTING_NUMBER_OF_REPLICAS, 0));
         for (int i = 0; i < 50; i++) {
-            client().prepareIndex("test", "test").setSource("{}").get();
+            client().prepareIndex("test", "test").setSource("{}", XContentType.JSON).get();
         }
         ensureGreen("test");
         InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) getInstanceFromNode(ClusterInfoService.class);
@@ -266,7 +268,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         logger.info("--> creating an index with data_path [{}]", startDir.toAbsolutePath().toString());
         createIndex(INDEX, sb);
         ensureGreen(INDEX);
-        client().prepareIndex(INDEX, "bar", "1").setSource("{}").setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex(INDEX, "bar", "1").setSource("{}", XContentType.JSON).setRefreshPolicy(IMMEDIATE).get();
 
         SearchResponse resp = client().prepareSearch(INDEX).setQuery(matchAllQuery()).get();
         assertThat("found the hit", resp.getHits().getTotalHits(), equalTo(1L));
@@ -323,7 +325,8 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder()
             .put(IndexSettings.INDEX_TRANSLOG_FLUSH_THRESHOLD_SIZE_SETTING.getKey(),
                 new ByteSizeValue(117 /* size of the operation + header&footer*/, ByteSizeUnit.BYTES)).build()).get();
-        client().prepareIndex("test", "test", "0").setSource("{}").setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
+        client().prepareIndex("test", "test", "0")
+            .setSource("{}", XContentType.JSON).setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
         assertFalse(shard.shouldFlush());
         ParsedDocument doc = testParsedDocument(
             "1",
@@ -331,12 +334,13 @@ public class IndexShardIT extends ESSingleNodeTestCase {
             null,
             SequenceNumbersService.UNASSIGNED_SEQ_NO,
             new ParseContext.Document(),
-            new BytesArray(new byte[]{1}), null);
+            new BytesArray(new byte[]{1}), XContentType.JSON, null);
         Engine.Index index = new Engine.Index(new Term("_uid", doc.uid()), doc);
         shard.index(index);
         assertTrue(shard.shouldFlush());
         assertEquals(2, shard.getEngine().getTranslog().totalOperations());
-        client().prepareIndex("test", "test", "2").setSource("{}").setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
+        client().prepareIndex("test", "test", "2").setSource("{}", XContentType.JSON)
+            .setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
         assertBusy(() -> { // this is async
             assertFalse(shard.shouldFlush());
         });
@@ -369,7 +373,8 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder().put(
             IndexSettings.INDEX_TRANSLOG_FLUSH_THRESHOLD_SIZE_SETTING.getKey(),
             new ByteSizeValue(117/* size of the operation + header&footer*/, ByteSizeUnit.BYTES)).build()).get();
-        client().prepareIndex("test", "test", "0").setSource("{}").setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
+        client().prepareIndex("test", "test", "0").setSource("{}", XContentType.JSON)
+            .setRefreshPolicy(randomBoolean() ? IMMEDIATE : NONE).get();
         assertFalse(shard.shouldFlush());
         final AtomicBoolean running = new AtomicBoolean(true);
         final int numThreads = randomIntBetween(2, 4);
@@ -394,7 +399,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         barrier.await();
         FlushStats flushStats = shard.flushStats();
         long total = flushStats.getTotal();
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         assertBusy(() -> assertEquals(total + 1, shard.flushStats().getTotal()));
         running.set(false);
         for (int i = 0; i < threads.length; i++) {
@@ -409,9 +414,9 @@ public class IndexShardIT extends ESSingleNodeTestCase {
         IndicesService indicesService = getInstanceFromNode(IndicesService.class);
         IndexService indexService = indicesService.indexService(resolveIndex("test"));
         IndexShard shard = indexService.getShardOrNull(0);
-        client().prepareIndex("test", "test", "0").setSource("{\"foo\" : \"bar\"}").get();
+        client().prepareIndex("test", "test", "0").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
         client().prepareDelete("test", "test", "0").get();
-        client().prepareIndex("test", "test", "1").setSource("{\"foo\" : \"bar\"}").setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("test", "test", "1").setSource("{\"foo\" : \"bar\"}", XContentType.JSON).setRefreshPolicy(IMMEDIATE).get();
 
         IndexSearcherWrapper wrapper = new IndexSearcherWrapper() {};
         shard.close("simon says", false);
diff --git a/core/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java b/core/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java
index 79e3868da4..4a03a26323 100644
--- a/core/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java
+++ b/core/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java
@@ -65,6 +65,7 @@ import org.elasticsearch.common.util.concurrent.AbstractRunnable;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.Engine;
@@ -558,7 +559,8 @@ public class IndexShardTests extends IndexShardTestCase {
         document.add(seqID.seqNo);
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
-        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, mappingUpdate);
+        return new ParsedDocument(versionField, seqID, id, type, routing, Arrays.asList(document), source, XContentType.JSON,
+            mappingUpdate);
     }
 
     public void testIndexingOperationsListeners() throws IOException {
diff --git a/core/src/test/java/org/elasticsearch/index/shard/RefreshListenersTests.java b/core/src/test/java/org/elasticsearch/index/shard/RefreshListenersTests.java
index d5c10dddc3..846ca6be20 100644
--- a/core/src/test/java/org/elasticsearch/index/shard/RefreshListenersTests.java
+++ b/core/src/test/java/org/elasticsearch/index/shard/RefreshListenersTests.java
@@ -37,6 +37,7 @@ import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.BigArrays;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.codec.CodecService;
@@ -338,7 +339,8 @@ public class RefreshListenersTests extends ESTestCase {
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
         BytesReference source = new BytesArray(new byte[] { 1 });
-        ParsedDocument doc = new ParsedDocument(versionField, seqID, id, type, null, Arrays.asList(document), source, null);
+        ParsedDocument doc = new ParsedDocument(versionField, seqID, id, type, null, Arrays.asList(document), source, XContentType.JSON,
+            null);
         Engine.Index index = new Engine.Index(new Term("_uid", doc.uid()), doc);
         return engine.index(index);
     }
diff --git a/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java b/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
index 1a9d7c97dc..0591500423 100644
--- a/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
+++ b/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
@@ -50,6 +50,7 @@ import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.engine.Engine.Operation.Origin;
@@ -2028,7 +2029,8 @@ public class TranslogTests extends ESTestCase {
         document.add(seqID.seqNo);
         document.add(seqID.seqNoDocValue);
         document.add(seqID.primaryTerm);
-        ParsedDocument doc = new ParsedDocument(versionField, seqID, "1", "type", null, Arrays.asList(document), B_1, null);
+        ParsedDocument doc = new ParsedDocument(versionField, seqID, "1", "type", null, Arrays.asList(document), B_1, XContentType.JSON,
+            null);
 
         Engine.Index eIndex = new Engine.Index(newUid(doc), doc, randomSeqNum, randomPrimaryTerm,
                 1, VersionType.INTERNAL, Origin.PRIMARY, 0, 0, false);
diff --git a/core/src/test/java/org/elasticsearch/indices/DateMathIndexExpressionsIntegrationIT.java b/core/src/test/java/org/elasticsearch/indices/DateMathIndexExpressionsIntegrationIT.java
index 82482b1f82..fe4ab2e363 100644
--- a/core/src/test/java/org/elasticsearch/indices/DateMathIndexExpressionsIntegrationIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/DateMathIndexExpressionsIntegrationIT.java
@@ -28,6 +28,7 @@ import org.elasticsearch.action.get.MultiGetResponse;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
@@ -57,9 +58,9 @@ public class DateMathIndexExpressionsIntegrationIT extends ESIntegTestCase {
         String dateMathExp1 = "<.marvel-{now/d}>";
         String dateMathExp2 = "<.marvel-{now/d-1d}>";
         String dateMathExp3 = "<.marvel-{now/d-2d}>";
-        client().prepareIndex(dateMathExp1, "type", "1").setSource("{}").get();
-        client().prepareIndex(dateMathExp2, "type", "2").setSource("{}").get();
-        client().prepareIndex(dateMathExp3, "type", "3").setSource("{}").get();
+        client().prepareIndex(dateMathExp1, "type", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp2, "type", "2").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp3, "type", "3").setSource("{}", XContentType.JSON).get();
         refresh();
 
         SearchResponse searchResponse = client().prepareSearch(dateMathExp1, dateMathExp2, dateMathExp3).get();
@@ -116,9 +117,9 @@ public class DateMathIndexExpressionsIntegrationIT extends ESIntegTestCase {
         String dateMathExp1 = "<.marvel-{now/d}>";
         String dateMathExp2 = "<.marvel-{now/d-1d}>";
         String dateMathExp3 = "<.marvel-{now/d-2d}>";
-        client().prepareIndex(dateMathExp1, "type", "1").setSource("{}").get();
-        client().prepareIndex(dateMathExp2, "type", "2").setSource("{}").get();
-        client().prepareIndex(dateMathExp3, "type", "3").setSource("{}").get();
+        client().prepareIndex(dateMathExp1, "type", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp2, "type", "2").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex(dateMathExp3, "type", "3").setSource("{}", XContentType.JSON).get();
         refresh();
 
         SearchResponse searchResponse = client().prepareSearch(dateMathExp1, dateMathExp2, dateMathExp3).get();
diff --git a/core/src/test/java/org/elasticsearch/indices/IndexingMemoryControllerTests.java b/core/src/test/java/org/elasticsearch/indices/IndexingMemoryControllerTests.java
index e9a717f663..fee2964fe1 100644
--- a/core/src/test/java/org/elasticsearch/indices/IndexingMemoryControllerTests.java
+++ b/core/src/test/java/org/elasticsearch/indices/IndexingMemoryControllerTests.java
@@ -25,6 +25,7 @@ import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.shard.IndexSearcherWrapper;
@@ -423,7 +424,7 @@ public class IndexingMemoryControllerTests extends ESSingleNodeTestCase {
         IndexService indexService = indicesService.indexService(resolveIndex("test"));
         IndexShard shard = indexService.getShardOrNull(0);
         for (int i = 0; i < 100; i++) {
-            client().prepareIndex("test", "test", Integer.toString(i)).setSource("{\"foo\" : \"bar\"}").get();
+            client().prepareIndex("test", "test", Integer.toString(i)).setSource("{\"foo\" : \"bar\"}", XContentType.JSON).get();
         }
 
         IndexSearcherWrapper wrapper = new IndexSearcherWrapper() {};
diff --git a/core/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java b/core/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java
index 012fae17f5..61d325a64e 100644
--- a/core/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java
+++ b/core/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java
@@ -37,6 +37,7 @@ import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.inject.ModuleTestCase;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.Analysis;
@@ -319,7 +320,8 @@ public class AnalysisModuleTests extends ModuleTestCase {
         String[] words = new String[]{"donau", "dampf", "schiff", "spargel", "creme", "suppe"};
 
         Path wordListFile = generateWordList(words);
-        settings = Settings.builder().loadFromSource("index: \n  word_list_path: " + wordListFile.toAbsolutePath()).build();
+        settings = Settings.builder().loadFromSource("index: \n  word_list_path: " + wordListFile.toAbsolutePath(), XContentType.YAML)
+            .build();
 
         Set<?> wordList = Analysis.getWordSet(env, Version.CURRENT, settings, "index.word_list");
         MatcherAssert.assertThat(wordList.size(), equalTo(6));
diff --git a/core/src/test/java/org/elasticsearch/indices/flush/FlushIT.java b/core/src/test/java/org/elasticsearch/indices/flush/FlushIT.java
index d974ea348c..50979cf611 100644
--- a/core/src/test/java/org/elasticsearch/indices/flush/FlushIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/flush/FlushIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.cluster.routing.allocation.command.MoveAllocationComman
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.engine.Engine;
@@ -57,7 +58,7 @@ public class FlushIT extends ESIntegTestCase {
         final int numIters = scaledRandomIntBetween(10, 30);
         for (int i = 0; i < numIters; i++) {
             for (int j = 0; j < 10; j++) {
-                client().prepareIndex("test", "test").setSource("{}").get();
+                client().prepareIndex("test", "test").setSource("{}", XContentType.JSON).get();
             }
             final CountDownLatch latch = new CountDownLatch(10);
             final CopyOnWriteArrayList<Throwable> errors = new CopyOnWriteArrayList<>();
@@ -164,7 +165,7 @@ public class FlushIT extends ESIntegTestCase {
             @Override
             public void run() {
                 while (stop.get() == false) {
-                    client().prepareIndex().setIndex("test").setType("doc").setSource("{}").get();
+                    client().prepareIndex().setIndex("test").setType("doc").setSource("{}", XContentType.JSON).get();
                     numDocs.incrementAndGet();
                 }
             }
diff --git a/core/src/test/java/org/elasticsearch/indices/flush/SyncedFlushSingleNodeTests.java b/core/src/test/java/org/elasticsearch/indices/flush/SyncedFlushSingleNodeTests.java
index c35df81cfd..59784456e9 100644
--- a/core/src/test/java/org/elasticsearch/indices/flush/SyncedFlushSingleNodeTests.java
+++ b/core/src/test/java/org/elasticsearch/indices/flush/SyncedFlushSingleNodeTests.java
@@ -25,6 +25,7 @@ import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.lease.Releasable;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.shard.IndexShard;
@@ -42,7 +43,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
 
     public void testModificationPreventsFlushing() throws InterruptedException {
         createIndex("test");
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         IndexService test = getInstanceFromNode(IndicesService.class).indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
 
@@ -54,7 +55,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
         assertEquals("exactly one active shard", 1, activeShards.size());
         Map<String, Engine.CommitId> commitIds = SyncedFlushUtil.sendPreSyncRequests(flushService, activeShards, state, shardId);
         assertEquals("exactly one commit id", 1, commitIds.size());
-        client().prepareIndex("test", "test", "2").setSource("{}").get();
+        client().prepareIndex("test", "test", "2").setSource("{}", XContentType.JSON).get();
         String syncId = UUIDs.base64UUID();
         SyncedFlushUtil.LatchedListener<ShardsSyncedFlushResult> listener = new SyncedFlushUtil.LatchedListener<>();
         flushService.sendSyncRequests(syncId, activeShards, state, commitIds, shardId, shardRoutingTable.size(), listener);
@@ -86,7 +87,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
 
     public void testSingleShardSuccess() throws InterruptedException {
         createIndex("test");
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         IndexService test = getInstanceFromNode(IndicesService.class).indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
 
@@ -106,7 +107,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
 
     public void testSyncFailsIfOperationIsInFlight() throws InterruptedException, ExecutionException {
         createIndex("test");
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         IndexService test = getInstanceFromNode(IndicesService.class).indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
 
@@ -161,7 +162,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
 
     public void testFailAfterIntermediateCommit() throws InterruptedException {
         createIndex("test");
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         IndexService test = getInstanceFromNode(IndicesService.class).indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
 
@@ -174,7 +175,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
         Map<String, Engine.CommitId> commitIds = SyncedFlushUtil.sendPreSyncRequests(flushService, activeShards, state, shardId);
         assertEquals("exactly one commit id", 1, commitIds.size());
         if (randomBoolean()) {
-            client().prepareIndex("test", "test", "2").setSource("{}").get();
+            client().prepareIndex("test", "test", "2").setSource("{}", XContentType.JSON).get();
         }
         client().admin().indices().prepareFlush("test").setForce(true).get();
         String syncId = UUIDs.base64UUID();
@@ -194,7 +195,7 @@ public class SyncedFlushSingleNodeTests extends ESSingleNodeTestCase {
 
     public void testFailWhenCommitIsMissing() throws InterruptedException {
         createIndex("test");
-        client().prepareIndex("test", "test", "1").setSource("{}").get();
+        client().prepareIndex("test", "test", "1").setSource("{}", XContentType.JSON).get();
         IndexService test = getInstanceFromNode(IndicesService.class).indexService(resolveIndex("test"));
         IndexShard shard = test.getShardOrNull(0);
 
diff --git a/core/src/test/java/org/elasticsearch/indices/memory/breaker/CircuitBreakerServiceIT.java b/core/src/test/java/org/elasticsearch/indices/memory/breaker/CircuitBreakerServiceIT.java
index 0ef915b827..484f6e5db7 100644
--- a/core/src/test/java/org/elasticsearch/indices/memory/breaker/CircuitBreakerServiceIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/memory/breaker/CircuitBreakerServiceIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider;
 import org.elasticsearch.common.breaker.CircuitBreaker;
@@ -40,6 +41,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.indices.breaker.BreakerSettings;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
 import org.elasticsearch.indices.breaker.CircuitBreakerStats;
@@ -177,7 +179,7 @@ public class CircuitBreakerServiceIT extends ESIntegTestCase {
 
         // Create an index where the mappings have a field data filter
         assertAcked(prepareCreate("ramtest").setSource("{\"mappings\": {\"type\": {\"properties\": {\"test\": " +
-                "{\"type\": \"text\",\"fielddata\": true,\"fielddata_frequency_filter\": {\"max\": 10000}}}}}}"));
+                "{\"type\": \"text\",\"fielddata\": true,\"fielddata_frequency_filter\": {\"max\": 10000}}}}}}", XContentType.JSON));
 
         ensureGreen("ramtest");
 
@@ -480,7 +482,7 @@ public class CircuitBreakerServiceIT extends ESIntegTestCase {
         BulkRequest bulkRequest = new BulkRequest();
         for (int i = 0; i < numRequests; i++) {
             IndexRequest indexRequest = new IndexRequest("index", "type", Integer.toString(i));
-            indexRequest.source("field", "value", "num", i);
+            indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field", "value", "num", i);
             bulkRequest.add(indexRequest);
         }
 
diff --git a/core/src/test/java/org/elasticsearch/indices/recovery/IndexRecoveryIT.java b/core/src/test/java/org/elasticsearch/indices/recovery/IndexRecoveryIT.java
index 424edb42e6..72a789ddc1 100644
--- a/core/src/test/java/org/elasticsearch/indices/recovery/IndexRecoveryIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/recovery/IndexRecoveryIT.java
@@ -43,6 +43,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.recovery.RecoveryStats;
 import org.elasticsearch.index.store.Store;
@@ -576,7 +577,7 @@ public class IndexRecoveryIT extends ESIntegTestCase {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName, "type").setSource("{}"));
+            requests.add(client().prepareIndex(indexName, "type").setSource("{}", XContentType.JSON));
         }
         indexRandom(true, requests);
         ensureSearchable(indexName);
@@ -686,7 +687,7 @@ public class IndexRecoveryIT extends ESIntegTestCase {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName, "type").setSource("{}"));
+            requests.add(client().prepareIndex(indexName, "type").setSource("{}", XContentType.JSON));
         }
         indexRandom(true, requests);
         ensureSearchable(indexName);
diff --git a/core/src/test/java/org/elasticsearch/indices/recovery/PeerRecoveryTargetServiceTests.java b/core/src/test/java/org/elasticsearch/indices/recovery/PeerRecoveryTargetServiceTests.java
index 1d266698db..bbe4d8ed12 100644
--- a/core/src/test/java/org/elasticsearch/indices/recovery/PeerRecoveryTargetServiceTests.java
+++ b/core/src/test/java/org/elasticsearch/indices/recovery/PeerRecoveryTargetServiceTests.java
@@ -22,6 +22,7 @@ package org.elasticsearch.indices.recovery;
 import org.elasticsearch.action.admin.indices.flush.FlushRequest;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.mapper.SourceToParse;
@@ -43,7 +44,7 @@ public class PeerRecoveryTargetServiceTests extends IndexShardTestCase {
             long seqNo = 0;
             for (int i = 0; i < docs; i++) {
                 Engine.Index indexOp = replica.prepareIndexOnReplica(
-                    SourceToParse.source(SourceToParse.Origin.REPLICA, index, "type", "doc_" + i, new BytesArray("{}")),
+                    SourceToParse.source(SourceToParse.Origin.REPLICA, index, "type", "doc_" + i, new BytesArray("{}"), XContentType.JSON),
                     seqNo++, 1, VersionType.EXTERNAL, IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP, false);
                 replica.index(indexOp);
                 if (rarely()) {
diff --git a/core/src/test/java/org/elasticsearch/indices/stats/IndexStatsIT.java b/core/src/test/java/org/elasticsearch/indices/stats/IndexStatsIT.java
index 519df00c06..91673630c3 100644
--- a/core/src/test/java/org/elasticsearch/indices/stats/IndexStatsIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/stats/IndexStatsIT.java
@@ -40,6 +40,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.MergePolicyConfig;
@@ -739,8 +740,8 @@ public class IndexStatsIT extends ESIntegTestCase {
 
         ensureGreen();
 
-        client().prepareIndex("test1", "bar", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}").execute().actionGet();
-        client().prepareIndex("test1", "baz", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}").execute().actionGet();
+        client().prepareIndex("test1", "bar", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", XContentType.JSON).get();
+        client().prepareIndex("test1", "baz", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", XContentType.JSON).get();
         refresh();
 
         client().prepareSearch("_all").addSort("bar", SortOrder.ASC).addSort("baz", SortOrder.ASC).execute().actionGet();
@@ -786,8 +787,8 @@ public class IndexStatsIT extends ESIntegTestCase {
                         "{ \"properties\": { \"bar\": { \"type\": \"text\", \"fields\": { \"completion\": { \"type\": \"completion\" }}},\"baz\": { \"type\": \"text\", \"fields\": { \"completion\": { \"type\": \"completion\" }}}}}"));
         ensureGreen();
 
-        client().prepareIndex("test1", "bar", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}").execute().actionGet();
-        client().prepareIndex("test1", "baz", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}").execute().actionGet();
+        client().prepareIndex("test1", "bar", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", XContentType.JSON).get();
+        client().prepareIndex("test1", "baz", Integer.toString(1)).setSource("{\"bar\":\"bar\",\"baz\":\"baz\"}", XContentType.JSON).get();
         refresh();
 
         IndicesStatsRequestBuilder builder = client().admin().indices().prepareStats();
@@ -1125,7 +1126,7 @@ public class IndexStatsIT extends ESIntegTestCase {
                     final IndexResponse response =
                         client()
                             .prepareIndex("test", "type", id)
-                            .setSource("{}")
+                            .setSource("{}", XContentType.JSON)
                             .get();
                     assertThat(response.getResult(), equalTo(DocWriteResponse.Result.CREATED));
                 }
diff --git a/core/src/test/java/org/elasticsearch/indices/template/SimpleIndexTemplateIT.java b/core/src/test/java/org/elasticsearch/indices/template/SimpleIndexTemplateIT.java
index 6469b660f0..cb6b8b752b 100644
--- a/core/src/test/java/org/elasticsearch/indices/template/SimpleIndexTemplateIT.java
+++ b/core/src/test/java/org/elasticsearch/indices/template/SimpleIndexTemplateIT.java
@@ -30,8 +30,10 @@ import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.AliasMetaData;
 import org.elasticsearch.common.ParsingException;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.indices.InvalidAliasNameException;
@@ -335,7 +337,7 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
         MapperParsingException e = expectThrows( MapperParsingException.class,
             () -> client().admin().indices().preparePutTemplate("template_1")
                 .setPatterns(Collections.singletonList("te*"))
-                .addMapping("type1", "abcde")
+                .addMapping("type1", "{\"foo\": \"abcde\"}", XContentType.JSON)
                 .get());
         assertThat(e.getMessage(), containsString("Failed to parse mapping "));
 
@@ -372,7 +374,7 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
 
         client().admin().indices().preparePutTemplate("template_with_aliases")
                 .setPatterns(Collections.singletonList("te*"))
-                .addMapping("type1", "{\"type1\" : {\"properties\" : {\"value\" : {\"type\" : \"text\"}}}}")
+                .addMapping("type1", "{\"type1\" : {\"properties\" : {\"value\" : {\"type\" : \"text\"}}}}", XContentType.JSON)
                 .addAlias(new Alias("simple_alias"))
                 .addAlias(new Alias("templated_alias-{index}"))
                 .addAlias(new Alias("filtered_alias").filter("{\"type\":{\"value\":\"type2\"}}"))
@@ -423,7 +425,7 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
 
     public void testIndexTemplateWithAliasesInSource() {
         client().admin().indices().preparePutTemplate("template_1")
-                .setSource("{\n" +
+                .setSource(new BytesArray("{\n" +
                         "    \"template\" : \"*\",\n" +
                         "    \"aliases\" : {\n" +
                         "        \"my_alias\" : {\n" +
@@ -434,7 +436,7 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
                         "            }\n" +
                         "        }\n" +
                         "    }\n" +
-                        "}").get();
+                        "}"), XContentType.JSON).get();
 
 
         assertAcked(prepareCreate("test_index").addMapping("type1").addMapping("type2"));
@@ -635,8 +637,8 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
                 .setOrder(0)
                 .addAlias(new Alias("alias4").filter(termQuery("field", "value"))).get();
 
-        client().prepareIndex("a1", "test", "test").setSource("{}").get();
-        BulkResponse response = client().prepareBulk().add(new IndexRequest("a2", "test", "test").source("{}")).get();
+        client().prepareIndex("a1", "test", "test").setSource("{}", XContentType.JSON).get();
+        BulkResponse response = client().prepareBulk().add(new IndexRequest("a2", "test", "test").source("{}", XContentType.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getIndex(), equalTo("a2"));
@@ -644,8 +646,8 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
         assertThat(response.getItems()[0].getId(), equalTo("test"));
         assertThat(response.getItems()[0].getVersion(), equalTo(1L));
 
-        client().prepareIndex("b1", "test", "test").setSource("{}").get();
-        response = client().prepareBulk().add(new IndexRequest("b2", "test", "test").source("{}")).get();
+        client().prepareIndex("b1", "test", "test").setSource("{}", XContentType.JSON).get();
+        response = client().prepareBulk().add(new IndexRequest("b2", "test", "test").source("{}", XContentType.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getIndex(), equalTo("b2"));
@@ -653,8 +655,8 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
         assertThat(response.getItems()[0].getId(), equalTo("test"));
         assertThat(response.getItems()[0].getVersion(), equalTo(1L));
 
-        client().prepareIndex("c1", "test", "test").setSource("{}").get();
-        response = client().prepareBulk().add(new IndexRequest("c2", "test", "test").source("{}")).get();
+        client().prepareIndex("c1", "test", "test").setSource("{}", XContentType.JSON).get();
+        response = client().prepareBulk().add(new IndexRequest("c2", "test", "test").source("{}", XContentType.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getIndex(), equalTo("c2"));
@@ -670,9 +672,9 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
         // So the aliases defined in the index template for this index will not fail
         // even though the fields in the alias fields don't exist yet and indexing into
         // an index that doesn't exist yet will succeed
-        client().prepareIndex("d1", "test", "test").setSource("{}").get();
+        client().prepareIndex("d1", "test", "test").setSource("{}", XContentType.JSON).get();
 
-        response = client().prepareBulk().add(new IndexRequest("d2", "test", "test").source("{}")).get();
+        response = client().prepareBulk().add(new IndexRequest("d2", "test", "test").source("{}", XContentType.JSON)).get();
         assertThat(response.hasFailures(), is(false));
         assertThat(response.getItems()[0].isFailed(), equalTo(false));
         assertThat(response.getItems()[0].getId(), equalTo("test"));
@@ -702,7 +704,7 @@ public class SimpleIndexTemplateIT extends ESIntegTestCase {
                     "                }\n" +
                     "            }\n" +
                     "         }\n" +
-                    "    }\n")
+                    "    }\n", XContentType.JSON)
             .get();
 
         // put template using custom_1 analyzer
diff --git a/core/src/test/java/org/elasticsearch/ingest/IngestClientIT.java b/core/src/test/java/org/elasticsearch/ingest/IngestClientIT.java
index 14335bde07..2b59f0d421 100644
--- a/core/src/test/java/org/elasticsearch/ingest/IngestClientIT.java
+++ b/core/src/test/java/org/elasticsearch/ingest/IngestClientIT.java
@@ -36,8 +36,10 @@ import org.elasticsearch.action.ingest.SimulateDocumentBaseResult;
 import org.elasticsearch.action.ingest.SimulatePipelineRequest;
 import org.elasticsearch.action.ingest.SimulatePipelineResponse;
 import org.elasticsearch.action.ingest.WritePipelineResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -81,7 +83,7 @@ public class IngestClientIT extends ESIntegTestCase {
             .endObject()
             .endArray()
             .endObject().bytes();
-        client().admin().cluster().preparePutPipeline("_id", pipelineSource)
+        client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON)
                 .get();
         GetPipelineResponse getResponse = client().admin().cluster().prepareGetPipeline("_id")
                 .get();
@@ -104,10 +106,10 @@ public class IngestClientIT extends ESIntegTestCase {
             .endObject().bytes();
         SimulatePipelineResponse response;
         if (randomBoolean()) {
-            response = client().admin().cluster().prepareSimulatePipeline(bytes)
+            response = client().admin().cluster().prepareSimulatePipeline(bytes, XContentType.JSON)
                 .setId("_id").get();
         } else {
-            SimulatePipelineRequest request = new SimulatePipelineRequest(bytes);
+            SimulatePipelineRequest request = new SimulatePipelineRequest(bytes, XContentType.JSON);
             request.setId("_id");
             response = client().admin().cluster().simulatePipeline(request).get();
         }
@@ -137,14 +139,14 @@ public class IngestClientIT extends ESIntegTestCase {
             .endObject()
             .endArray()
             .endObject().bytes();
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
         int numRequests = scaledRandomIntBetween(32, 128);
         BulkRequest bulkRequest = new BulkRequest();
         for (int i = 0; i < numRequests; i++) {
             IndexRequest indexRequest = new IndexRequest("index", "type", Integer.toString(i)).setPipeline("_id");
-            indexRequest.source("field", "value", "fail", i % 2 == 0);
+            indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field", "value", "fail", i % 2 == 0);
             bulkRequest.add(indexRequest);
         }
 
@@ -177,7 +179,7 @@ public class IngestClientIT extends ESIntegTestCase {
             .endObject()
             .endArray()
             .endObject().bytes();
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
         client().admin().cluster().putPipeline(putPipelineRequest).get();
 
         GetPipelineRequest getPipelineRequest = new GetPipelineRequest("_id");
@@ -219,7 +221,7 @@ public class IngestClientIT extends ESIntegTestCase {
                 .endObject()
                 .endArray()
                 .endObject().bytes();
-        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source);
+        PutPipelineRequest putPipelineRequest = new PutPipelineRequest("_id", source, XContentType.JSON);
         try {
             client().admin().cluster().putPipeline(putPipelineRequest).get();
         } catch (ExecutionException e) {
diff --git a/core/src/test/java/org/elasticsearch/ingest/IngestMetadataTests.java b/core/src/test/java/org/elasticsearch/ingest/IngestMetadataTests.java
index e2fca8b411..518b775d7f 100644
--- a/core/src/test/java/org/elasticsearch/ingest/IngestMetadataTests.java
+++ b/core/src/test/java/org/elasticsearch/ingest/IngestMetadataTests.java
@@ -42,10 +42,10 @@ public class IngestMetadataTests extends ESTestCase {
 
     public void testFromXContent() throws IOException {
         PipelineConfiguration pipeline = new PipelineConfiguration(
-            "1",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}")
+            "1", new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"), XContentType.JSON
         );
         PipelineConfiguration pipeline2 = new PipelineConfiguration(
-            "2",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field1\", \"value\": \"_value1\"}}]}")
+            "2", new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field1\", \"value\": \"_value1\"}}]}"), XContentType.JSON
         );
         Map<String, PipelineConfiguration> map = new HashMap<>();
         map.put(pipeline.getId(), pipeline);
@@ -72,14 +72,14 @@ public class IngestMetadataTests extends ESTestCase {
         BytesReference pipelineConfig = new BytesArray("{}");
 
         Map<String, PipelineConfiguration> pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig));
-        pipelines.put("2", new PipelineConfiguration("2", pipelineConfig));
+        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, XContentType.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", pipelineConfig, XContentType.JSON));
         IngestMetadata ingestMetadata1 = new IngestMetadata(pipelines);
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig));
-        pipelines.put("3", new PipelineConfiguration("3", pipelineConfig));
-        pipelines.put("4", new PipelineConfiguration("4", pipelineConfig));
+        pipelines.put("1", new PipelineConfiguration("1", pipelineConfig, XContentType.JSON));
+        pipelines.put("3", new PipelineConfiguration("3", pipelineConfig, XContentType.JSON));
+        pipelines.put("4", new PipelineConfiguration("4", pipelineConfig, XContentType.JSON));
         IngestMetadata ingestMetadata2 = new IngestMetadata(pipelines);
 
         IngestMetadata.IngestMetadataDiff diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata2.diff(ingestMetadata1);
@@ -92,13 +92,13 @@ public class IngestMetadataTests extends ESTestCase {
         IngestMetadata endResult = (IngestMetadata) diff.apply(ingestMetadata2);
         assertThat(endResult, not(equalTo(ingestMetadata1)));
         assertThat(endResult.getPipelines().size(), equalTo(3));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig)));
-        assertThat(endResult.getPipelines().get("3"), equalTo(new PipelineConfiguration("3", pipelineConfig)));
-        assertThat(endResult.getPipelines().get("4"), equalTo(new PipelineConfiguration("4", pipelineConfig)));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("3"), equalTo(new PipelineConfiguration("3", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("4"), equalTo(new PipelineConfiguration("4", pipelineConfig, XContentType.JSON)));
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}")));
-        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{}")));
+        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), XContentType.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{}"), XContentType.JSON));
         IngestMetadata ingestMetadata3 = new IngestMetadata(pipelines);
 
         diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata3.diff(ingestMetadata1);
@@ -108,12 +108,12 @@ public class IngestMetadataTests extends ESTestCase {
         endResult = (IngestMetadata) diff.apply(ingestMetadata3);
         assertThat(endResult, equalTo(ingestMetadata1));
         assertThat(endResult.getPipelines().size(), equalTo(2));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig)));
-        assertThat(endResult.getPipelines().get("2"), equalTo(new PipelineConfiguration("2", pipelineConfig)));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("2"), equalTo(new PipelineConfiguration("2", pipelineConfig, XContentType.JSON)));
 
         pipelines = new HashMap<>();
-        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}")));
-        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}")));
+        pipelines.put("1", new PipelineConfiguration("1", new BytesArray("{}"), XContentType.JSON));
+        pipelines.put("2", new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), XContentType.JSON));
         IngestMetadata ingestMetadata4 = new IngestMetadata(pipelines);
 
         diff = (IngestMetadata.IngestMetadataDiff) ingestMetadata4.diff(ingestMetadata1);
@@ -123,7 +123,8 @@ public class IngestMetadataTests extends ESTestCase {
         endResult = (IngestMetadata) diff.apply(ingestMetadata4);
         assertThat(endResult, not(equalTo(ingestMetadata1)));
         assertThat(endResult.getPipelines().size(), equalTo(2));
-        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig)));
-        assertThat(endResult.getPipelines().get("2"), equalTo(new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"))));
+        assertThat(endResult.getPipelines().get("1"), equalTo(new PipelineConfiguration("1", pipelineConfig, XContentType.JSON)));
+        assertThat(endResult.getPipelines().get("2"),
+            equalTo(new PipelineConfiguration("2", new BytesArray("{\"key\" : \"value\"}"), XContentType.JSON)));
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java b/core/src/test/java/org/elasticsearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
index 83072636b7..1a8e6e873e 100644
--- a/core/src/test/java/org/elasticsearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
+++ b/core/src/test/java/org/elasticsearch/ingest/IngestProcessorNotInstalledOnAllNodesIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.action.ingest.WritePipelineResponse;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.node.NodeService;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -69,7 +70,7 @@ public class IngestProcessorNotInstalledOnAllNodesIT extends ESIntegTestCase {
         ensureStableCluster(2, node2);
 
         try {
-            client().admin().cluster().preparePutPipeline("_id", pipelineSource).get();
+            client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
             fail("exception expected");
         } catch (IllegalArgumentException e) {
             assertThat(e.getMessage(), containsString("Processor type [test] is not installed on node"));
@@ -82,7 +83,7 @@ public class IngestProcessorNotInstalledOnAllNodesIT extends ESIntegTestCase {
         internalCluster().startNode();
 
         try {
-            client().admin().cluster().preparePutPipeline("_id", pipelineSource).get();
+            client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
             fail("exception expected");
         } catch (ElasticsearchParseException e) {
             assertThat(e.getMessage(), equalTo("No processor type exists with name [test]"));
@@ -95,7 +96,7 @@ public class IngestProcessorNotInstalledOnAllNodesIT extends ESIntegTestCase {
         installPlugin = true;
         String node1 = internalCluster().startNode();
 
-        WritePipelineResponse response = client().admin().cluster().preparePutPipeline("_id", pipelineSource).get();
+        WritePipelineResponse response = client().admin().cluster().preparePutPipeline("_id", pipelineSource, XContentType.JSON).get();
         assertThat(response.isAcknowledged(), is(true));
         Pipeline pipeline = internalCluster().getInstance(NodeService.class, node1).getIngestService().getPipelineStore().get("_id");
         assertThat(pipeline, notNullValue());
diff --git a/core/src/test/java/org/elasticsearch/ingest/PipelineConfigurationTests.java b/core/src/test/java/org/elasticsearch/ingest/PipelineConfigurationTests.java
new file mode 100644
index 0000000000..f41d01b32c
--- /dev/null
+++ b/core/src/test/java/org/elasticsearch/ingest/PipelineConfigurationTests.java
@@ -0,0 +1,89 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.ingest;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.ContextParser;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+public class PipelineConfigurationTests extends ESTestCase {
+
+    public void testSerialization() throws IOException {
+        PipelineConfiguration configuration = new PipelineConfiguration("1",
+            new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
+        assertEquals(XContentType.JSON, configuration.getXContentType());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        configuration.writeTo(out);
+        StreamInput in = StreamInput.wrap(out.bytes().toBytesRef().bytes);
+        PipelineConfiguration serialized = PipelineConfiguration.readFrom(in);
+        assertEquals(XContentType.JSON, serialized.getXContentType());
+        assertEquals("{}", serialized.getConfig().utf8ToString());
+    }
+
+    public void testSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("ATECe30AAAA=");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            PipelineConfiguration configuration = PipelineConfiguration.readFrom(in);
+            assertEquals(XContentType.JSON, configuration.getXContentType());
+            assertEquals("{}", configuration.getConfig().utf8ToString());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                configuration.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+
+    public void testParser() throws IOException {
+        ContextParser<Void, PipelineConfiguration> parser = PipelineConfiguration.getParser();
+        XContentType xContentType = randomFrom(XContentType.values());
+        final BytesReference bytes;
+        try (XContentBuilder builder = XContentBuilder.builder(xContentType.xContent())) {
+            new PipelineConfiguration("1", new BytesArray("{}".getBytes(StandardCharsets.UTF_8)), XContentType.JSON)
+                .toXContent(builder, ToXContent.EMPTY_PARAMS);
+            bytes = builder.bytes();
+        }
+
+        XContentParser xContentParser = xContentType.xContent().createParser(NamedXContentRegistry.EMPTY, bytes);
+        PipelineConfiguration parsed = parser.parse(xContentParser, null);
+        assertEquals(xContentType, parsed.getXContentType());
+        assertEquals("{}", XContentHelper.convertToJson(parsed.getConfig(), false, parsed.getXContentType()));
+        assertEquals("1", parsed.getId());
+    }
+}
diff --git a/core/src/test/java/org/elasticsearch/ingest/PipelineExecutionServiceTests.java b/core/src/test/java/org/elasticsearch/ingest/PipelineExecutionServiceTests.java
index c00e9254ab..7ad445e301 100644
--- a/core/src/test/java/org/elasticsearch/ingest/PipelineExecutionServiceTests.java
+++ b/core/src/test/java/org/elasticsearch/ingest/PipelineExecutionServiceTests.java
@@ -25,8 +25,10 @@ import org.elasticsearch.action.bulk.BulkRequest;
 import org.elasticsearch.action.delete.DeleteRequest;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.update.UpdateRequest;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.hamcrest.CustomTypeSafeMatcher;
@@ -273,7 +275,7 @@ public class PipelineExecutionServiceTests extends ESTestCase {
                 }
             } else {
                 IndexRequest indexRequest = new IndexRequest("_index", "_type", "_id").setPipeline(pipelineId);
-                indexRequest.source("field1", "value1");
+                indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
                 request = indexRequest;
                 numIndexRequests++;
             }
@@ -303,7 +305,7 @@ public class PipelineExecutionServiceTests extends ESTestCase {
         int numRequest = scaledRandomIntBetween(8, 64);
         for (int i = 0; i < numRequest; i++) {
             IndexRequest indexRequest = new IndexRequest("_index", "_type", "_id").setPipeline(pipelineId);
-            indexRequest.source("field1", "value1");
+            indexRequest.source(Requests.INDEX_CONTENT_TYPE, "field1", "value1");
             bulkRequest.add(indexRequest);
         }
 
@@ -331,8 +333,8 @@ public class PipelineExecutionServiceTests extends ESTestCase {
         when(store.get("_id2")).thenReturn(new Pipeline("_id2", null, null, new CompoundProcessor(mock(Processor.class))));
 
         Map<String, PipelineConfiguration> configurationMap = new HashMap<>();
-        configurationMap.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{}")));
-        configurationMap.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{}")));
+        configurationMap.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{}"), XContentType.JSON));
+        configurationMap.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{}"), XContentType.JSON));
         executionService.updatePipelineStats(new IngestMetadata(configurationMap));
 
         @SuppressWarnings("unchecked")
@@ -361,14 +363,14 @@ public class PipelineExecutionServiceTests extends ESTestCase {
     // issue: https://github.com/elastic/elasticsearch/issues/18126
     public void testUpdatingStatsWhenRemovingPipelineWorks() throws Exception {
         Map<String, PipelineConfiguration> configurationMap = new HashMap<>();
-        configurationMap.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{}")));
-        configurationMap.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{}")));
+        configurationMap.put("_id1", new PipelineConfiguration("_id1", new BytesArray("{}"), XContentType.JSON));
+        configurationMap.put("_id2", new PipelineConfiguration("_id2", new BytesArray("{}"), XContentType.JSON));
         executionService.updatePipelineStats(new IngestMetadata(configurationMap));
         assertThat(executionService.stats().getStatsPerPipeline(), hasKey("_id1"));
         assertThat(executionService.stats().getStatsPerPipeline(), hasKey("_id2"));
 
         configurationMap = new HashMap<>();
-        configurationMap.put("_id3", new PipelineConfiguration("_id3", new BytesArray("{}")));
+        configurationMap.put("_id3", new PipelineConfiguration("_id3", new BytesArray("{}"), XContentType.JSON));
         executionService.updatePipelineStats(new IngestMetadata(configurationMap));
         assertThat(executionService.stats().getStatsPerPipeline(), not(hasKey("_id1")));
         assertThat(executionService.stats().getStatsPerPipeline(), not(hasKey("_id2")));
diff --git a/core/src/test/java/org/elasticsearch/ingest/PipelineStoreTests.java b/core/src/test/java/org/elasticsearch/ingest/PipelineStoreTests.java
index 5967354710..e91bb7e2e6 100644
--- a/core/src/test/java/org/elasticsearch/ingest/PipelineStoreTests.java
+++ b/core/src/test/java/org/elasticsearch/ingest/PipelineStoreTests.java
@@ -30,6 +30,7 @@ import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 import org.junit.Before;
 
@@ -102,7 +103,7 @@ public class PipelineStoreTests extends ESTestCase {
         assertThat(store.pipelines.size(), is(0));
 
         PipelineConfiguration pipeline = new PipelineConfiguration(
-            "_id",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}")
+            "_id",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"), XContentType.JSON
         );
         IngestMetadata ingestMetadata = new IngestMetadata(Collections.singletonMap("_id", pipeline));
         clusterState = ClusterState.builder(clusterState)
@@ -123,7 +124,7 @@ public class PipelineStoreTests extends ESTestCase {
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
 
         // add a new pipeline:
-        PutPipelineRequest putRequest = new PutPipelineRequest(id, new BytesArray("{\"processors\": []}"));
+        PutPipelineRequest putRequest = new PutPipelineRequest(id, new BytesArray("{\"processors\": []}"), XContentType.JSON);
         ClusterState previousClusterState = clusterState;
         clusterState = store.innerPut(putRequest, clusterState);
         store.innerUpdatePipelines(previousClusterState, clusterState);
@@ -134,7 +135,8 @@ public class PipelineStoreTests extends ESTestCase {
         assertThat(pipeline.getProcessors().size(), equalTo(0));
 
         // overwrite existing pipeline:
-        putRequest = new PutPipelineRequest(id, new BytesArray("{\"processors\": [], \"description\": \"_description\"}"));
+        putRequest =
+            new PutPipelineRequest(id, new BytesArray("{\"processors\": [], \"description\": \"_description\"}"), XContentType.JSON);
         previousClusterState = clusterState;
         clusterState = store.innerPut(putRequest, clusterState);
         store.innerUpdatePipelines(previousClusterState, clusterState);
@@ -151,7 +153,8 @@ public class PipelineStoreTests extends ESTestCase {
         assertThat(pipeline, nullValue());
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
 
-        PutPipelineRequest putRequest = new PutPipelineRequest(id, new BytesArray("{\"description\": \"empty processors\"}"));
+        PutPipelineRequest putRequest =
+            new PutPipelineRequest(id, new BytesArray("{\"description\": \"empty processors\"}"), XContentType.JSON);
         ClusterState previousClusterState = clusterState;
         clusterState = store.innerPut(putRequest, clusterState);
         try {
@@ -166,7 +169,7 @@ public class PipelineStoreTests extends ESTestCase {
 
     public void testDelete() {
         PipelineConfiguration config = new PipelineConfiguration(
-            "_id",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}")
+            "_id",new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"), XContentType.JSON
         );
         IngestMetadata ingestMetadata = new IngestMetadata(Collections.singletonMap("_id", config));
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
@@ -197,9 +200,9 @@ public class PipelineStoreTests extends ESTestCase {
         BytesArray definition = new BytesArray(
             "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"
         );
-        pipelines.put("p1", new PipelineConfiguration("p1", definition));
-        pipelines.put("p2", new PipelineConfiguration("p2", definition));
-        pipelines.put("q1", new PipelineConfiguration("q1", definition));
+        pipelines.put("p1", new PipelineConfiguration("p1", definition, XContentType.JSON));
+        pipelines.put("p2", new PipelineConfiguration("p2", definition, XContentType.JSON));
+        pipelines.put("q1", new PipelineConfiguration("q1", definition, XContentType.JSON));
         IngestMetadata ingestMetadata = new IngestMetadata(pipelines);
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
         ClusterState previousClusterState = clusterState;
@@ -245,7 +248,7 @@ public class PipelineStoreTests extends ESTestCase {
         BytesArray definition = new BytesArray(
             "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"
         );
-        pipelines.put("p1", new PipelineConfiguration("p1", definition));
+        pipelines.put("p1", new PipelineConfiguration("p1", definition, XContentType.JSON));
         IngestMetadata ingestMetadata = new IngestMetadata(pipelines);
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build();
         ClusterState previousClusterState = clusterState;
@@ -266,10 +269,10 @@ public class PipelineStoreTests extends ESTestCase {
     public void testGetPipelines() {
         Map<String, PipelineConfiguration> configs = new HashMap<>();
         configs.put("_id1", new PipelineConfiguration(
-            "_id1", new BytesArray("{\"processors\": []}")
+            "_id1", new BytesArray("{\"processors\": []}"), XContentType.JSON
         ));
         configs.put("_id2", new PipelineConfiguration(
-            "_id2", new BytesArray("{\"processors\": []}")
+            "_id2", new BytesArray("{\"processors\": []}"), XContentType.JSON
         ));
 
         assertThat(store.innerGetPipelines(null, "_id1").isEmpty(), is(true));
@@ -311,7 +314,7 @@ public class PipelineStoreTests extends ESTestCase {
         ClusterState clusterState = ClusterState.builder(new ClusterName("_name")).build(); // Start empty
 
         PutPipelineRequest putRequest = new PutPipelineRequest(id,
-                new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"));
+                new BytesArray("{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"), XContentType.JSON);
         ClusterState previousClusterState = clusterState;
         clusterState = store.innerPut(putRequest, clusterState);
         store.innerUpdatePipelines(previousClusterState, clusterState);
@@ -332,7 +335,8 @@ public class PipelineStoreTests extends ESTestCase {
 
     public void testValidate() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest("_id", new BytesArray(
-                "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}},{\"remove\" : {\"field\": \"_field\"}}]}"));
+                "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}},{\"remove\" : {\"field\": \"_field\"}}]}"),
+            XContentType.JSON);
 
         DiscoveryNode node1 = new DiscoveryNode("_node_id1", buildNewFakeTransportAddress(),
                 emptyMap(), emptySet(), Version.CURRENT);
@@ -355,7 +359,7 @@ public class PipelineStoreTests extends ESTestCase {
 
     public void testValidateNoIngestInfo() throws Exception {
         PutPipelineRequest putRequest = new PutPipelineRequest("_id", new BytesArray(
-                "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"));
+                "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"_value\"}}]}"), XContentType.JSON);
         try {
             store.validatePipeline(Collections.emptyMap(), putRequest);
             fail("exception expected");
diff --git a/core/src/test/java/org/elasticsearch/mget/SimpleMgetIT.java b/core/src/test/java/org/elasticsearch/mget/SimpleMgetIT.java
index 5c499eae4d..3f0eac7762 100644
--- a/core/src/test/java/org/elasticsearch/mget/SimpleMgetIT.java
+++ b/core/src/test/java/org/elasticsearch/mget/SimpleMgetIT.java
@@ -27,6 +27,7 @@ import org.elasticsearch.action.get.MultiGetResponse;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -143,7 +144,7 @@ public class SimpleMgetIT extends ESIntegTestCase {
                 .field("excluded", "should not be seen")
                 .endObject().bytes();
         for (int i = 0; i < 100; i++) {
-            client().prepareIndex("test", "type", Integer.toString(i)).setSource(sourceBytesRef).get();
+            client().prepareIndex("test", "type", Integer.toString(i)).setSource(sourceBytesRef, XContentType.JSON).get();
         }
 
         MultiGetRequestBuilder request = client().prepareMultiGet();
diff --git a/core/src/test/java/org/elasticsearch/recovery/RelocationIT.java b/core/src/test/java/org/elasticsearch/recovery/RelocationIT.java
index 8d19f90958..56f9b265c0 100644
--- a/core/src/test/java/org/elasticsearch/recovery/RelocationIT.java
+++ b/core/src/test/java/org/elasticsearch/recovery/RelocationIT.java
@@ -42,6 +42,7 @@ import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.seqno.SeqNoStats;
 import org.elasticsearch.index.seqno.SequenceNumbersService;
@@ -334,12 +335,12 @@ public class RelocationIT extends ESIntegTestCase {
 
             List<IndexRequestBuilder> builders1 = new ArrayList<>();
             for (int numDocs = randomIntBetween(10, 30); numDocs > 0; numDocs--) {
-                builders1.add(client().prepareIndex("test", "type").setSource("{}"));
+                builders1.add(client().prepareIndex("test", "type").setSource("{}", XContentType.JSON));
             }
 
             List<IndexRequestBuilder> builders2 = new ArrayList<>();
             for (int numDocs = randomIntBetween(10, 30); numDocs > 0; numDocs--) {
-                builders2.add(client().prepareIndex("test", "type").setSource("{}"));
+                builders2.add(client().prepareIndex("test", "type").setSource("{}", XContentType.JSON));
             }
 
             logger.info("--> START relocate the shard from {} to {}", nodes[fromNode], nodes[toNode]);
@@ -392,7 +393,7 @@ public class RelocationIT extends ESIntegTestCase {
         List<IndexRequestBuilder> requests = new ArrayList<>();
         int numDocs = scaledRandomIntBetween(25, 250);
         for (int i = 0; i < numDocs; i++) {
-            requests.add(client().prepareIndex(indexName, "type").setSource("{}"));
+            requests.add(client().prepareIndex(indexName, "type").setSource("{}", XContentType.JSON));
         }
         indexRandom(true, requests);
         assertFalse(client().admin().cluster().prepareHealth().setWaitForNodes("3").setWaitForGreenStatus().get().isTimedOut());
diff --git a/core/src/test/java/org/elasticsearch/recovery/SimpleRecoveryIT.java b/core/src/test/java/org/elasticsearch/recovery/SimpleRecoveryIT.java
index e860cfc9eb..bf8bce8ae6 100644
--- a/core/src/test/java/org/elasticsearch/recovery/SimpleRecoveryIT.java
+++ b/core/src/test/java/org/elasticsearch/recovery/SimpleRecoveryIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.admin.indices.flush.FlushResponse;
 import org.elasticsearch.action.admin.indices.refresh.RefreshResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import static org.elasticsearch.client.Requests.flushRequest;
@@ -52,12 +53,12 @@ public class SimpleRecoveryIT extends ESIntegTestCase {
 
         NumShards numShards = getNumShards("test");
 
-        client().index(indexRequest("test").type("type1").id("1").source(source("1", "test"))).actionGet();
+        client().index(indexRequest("test").type("type1").id("1").source(source("1", "test"), XContentType.JSON)).actionGet();
         FlushResponse flushResponse = client().admin().indices().flush(flushRequest("test")).actionGet();
         assertThat(flushResponse.getTotalShards(), equalTo(numShards.totalNumShards));
         assertThat(flushResponse.getSuccessfulShards(), equalTo(numShards.numPrimaries));
         assertThat(flushResponse.getFailedShards(), equalTo(0));
-        client().index(indexRequest("test").type("type1").id("2").source(source("2", "test"))).actionGet();
+        client().index(indexRequest("test").type("type1").id("2").source(source("2", "test"), XContentType.JSON)).actionGet();
         RefreshResponse refreshResponse = client().admin().indices().refresh(refreshRequest("test")).actionGet();
         assertThat(refreshResponse.getTotalShards(), equalTo(numShards.totalNumShards));
         assertThat(refreshResponse.getSuccessfulShards(), equalTo(numShards.numPrimaries));
diff --git a/core/src/test/java/org/elasticsearch/rest/BytesRestResponseTests.java b/core/src/test/java/org/elasticsearch/rest/BytesRestResponseTests.java
index 4e8d9b8600..431bc152bd 100644
--- a/core/src/test/java/org/elasticsearch/rest/BytesRestResponseTests.java
+++ b/core/src/test/java/org/elasticsearch/rest/BytesRestResponseTests.java
@@ -165,7 +165,7 @@ public class BytesRestResponseTests extends ESTestCase {
 
     public void testResponseWhenPathContainsEncodingError() throws IOException {
         final String path = "%a";
-        final RestRequest request = new RestRequest(NamedXContentRegistry.EMPTY, Collections.emptyMap(), path) {
+        final RestRequest request = new RestRequest(NamedXContentRegistry.EMPTY, Collections.emptyMap(), path, Collections.emptyMap()) {
             @Override
             public Method method() {
                 return null;
@@ -185,16 +185,6 @@ public class BytesRestResponseTests extends ESTestCase {
             public BytesReference content() {
                 return null;
             }
-
-            @Override
-            public String header(String name) {
-                return null;
-            }
-
-            @Override
-            public Iterable<Map.Entry<String, String>> headers() {
-                return null;
-            }
         };
         final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> RestUtils.decodeComponent(request.rawPath()));
         final RestChannel channel = new DetailedExceptionRestChannel(request);
diff --git a/core/src/test/java/org/elasticsearch/rest/RestControllerTests.java b/core/src/test/java/org/elasticsearch/rest/RestControllerTests.java
index e706455490..79c6f6561e 100644
--- a/core/src/test/java/org/elasticsearch/rest/RestControllerTests.java
+++ b/core/src/test/java/org/elasticsearch/rest/RestControllerTests.java
@@ -23,6 +23,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -41,10 +42,11 @@ import org.elasticsearch.common.transport.TransportAddress;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.http.HttpInfo;
 import org.elasticsearch.http.HttpServerTransport;
 import org.elasticsearch.http.HttpStats;
-import org.elasticsearch.indices.breaker.CircuitBreakerService;
+import org.elasticsearch.http.HttpTransportSettings;
 import org.elasticsearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.rest.FakeRestRequest;
@@ -91,19 +93,17 @@ public class RestControllerTests extends ESTestCase {
         final ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
         Set<String> headers = new HashSet<>(Arrays.asList("header.1", "header.2"));
         final RestController restController = new RestController(Settings.EMPTY, headers, null, null, circuitBreakerService);
-        restController.registerHandler(RestRequest.Method.GET, "/",
-            (RestRequest request, RestChannel channel, NodeClient client) -> {
+        threadContext.putHeader("header.3", "true");
+        Map<String, List<String>> restHeaders = new HashMap<>();
+        restHeaders.put("header.1", Collections.singletonList("true"));
+        restHeaders.put("header.2", Collections.singletonList("true"));
+        restHeaders.put("header.3", Collections.singletonList("false"));
+        restController.dispatchRequest(new FakeRestRequest.Builder(xContentRegistry()).withHeaders(restHeaders).build(), null, null,
+                threadContext, (RestRequest request, RestChannel channel, NodeClient client) -> {
                 assertEquals("true", threadContext.getHeader("header.1"));
                 assertEquals("true", threadContext.getHeader("header.2"));
                 assertNull(threadContext.getHeader("header.3"));
             });
-        threadContext.putHeader("header.3", "true");
-        Map<String, String> restHeaders = new HashMap<>();
-        restHeaders.put("header.1", "true");
-        restHeaders.put("header.2", "true");
-        restHeaders.put("header.3", "false");
-        restController.dispatchRequest(new FakeRestRequest.Builder(xContentRegistry()).withHeaders(restHeaders).build(), null, null,
-                threadContext);
         assertNull(threadContext.getHeader("header.1"));
         assertNull(threadContext.getHeader("header.2"));
         assertEquals("true", threadContext.getHeader("header.3"));
@@ -172,9 +172,8 @@ public class RestControllerTests extends ESTestCase {
         };
         final RestController restController = new RestController(Settings.EMPTY, Collections.emptySet(), wrapper, null,
             circuitBreakerService);
-        restController.registerHandler(RestRequest.Method.GET, "/", handler);
         final ThreadContext threadContext = new ThreadContext(Settings.EMPTY);
-        restController.dispatchRequest(new FakeRestRequest.Builder(xContentRegistry()).build(), null, null, threadContext);
+        restController.dispatchRequest(new FakeRestRequest.Builder(xContentRegistry()).build(), null, null, threadContext, handler);
         assertTrue(wrapperCalled.get());
         assertFalse(handlerCalled.get());
     }
@@ -203,7 +202,7 @@ public class RestControllerTests extends ESTestCase {
     public void testDispatchRequestAddsAndFreesBytesOnSuccess() {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAsciiOfLength(contentLength);
-        TestRestRequest request = new TestRestRequest("/", content);
+        TestRestRequest request = new TestRestRequest("/", content, XContentType.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.OK);
 
         restController.dispatchRequest(request, channel, new ThreadContext(Settings.EMPTY));
@@ -215,7 +214,7 @@ public class RestControllerTests extends ESTestCase {
     public void testDispatchRequestAddsAndFreesBytesOnError() {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAsciiOfLength(contentLength);
-        TestRestRequest request = new TestRestRequest("/error", content);
+        TestRestRequest request = new TestRestRequest("/error", content, XContentType.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.BAD_REQUEST);
 
         restController.dispatchRequest(request, channel, new ThreadContext(Settings.EMPTY));
@@ -228,7 +227,7 @@ public class RestControllerTests extends ESTestCase {
         int contentLength = BREAKER_LIMIT.bytesAsInt();
         String content = randomAsciiOfLength(contentLength);
         // we will produce an error in the rest handler and one more when sending the error response
-        TestRestRequest request = new TestRestRequest("/error", content);
+        TestRestRequest request = new TestRestRequest("/error", content, XContentType.JSON);
         ExceptionThrowingChannel channel = new ExceptionThrowingChannel(request, true);
 
         restController.dispatchRequest(request, channel, new ThreadContext(Settings.EMPTY));
@@ -240,7 +239,7 @@ public class RestControllerTests extends ESTestCase {
     public void testDispatchRequestLimitsBytes() {
         int contentLength = BREAKER_LIMIT.bytesAsInt() + 1;
         String content = randomAsciiOfLength(contentLength);
-        TestRestRequest request = new TestRestRequest("/", content);
+        TestRestRequest request = new TestRestRequest("/", content, XContentType.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.SERVICE_UNAVAILABLE);
 
         restController.dispatchRequest(request, channel, new ThreadContext(Settings.EMPTY));
@@ -249,6 +248,67 @@ public class RestControllerTests extends ESTestCase {
         assertEquals(0, inFlightRequestsBreaker.getUsed());
     }
 
+    public void testDispatchRequiresContentTypeForRequestsWithContent() {
+        String content = randomAsciiOfLengthBetween(1, BREAKER_LIMIT.bytesAsInt());
+        TestRestRequest request = new TestRestRequest("/", content, null);
+        AssertingChannel channel = new AssertingChannel(request, true, RestStatus.NOT_ACCEPTABLE);
+        restController = new RestController(
+            Settings.builder().put(HttpTransportSettings.SETTING_HTTP_CONTENT_TYPE_REQUIRED.getKey(), true).build(),
+            Collections.emptySet(), null, null, circuitBreakerService);
+        restController.registerHandler(RestRequest.Method.GET, "/",
+            (r, c, client) -> c.sendResponse(
+                new BytesRestResponse(RestStatus.OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY)));
+
+        assertFalse(channel.sendResponseCalled.get());
+        restController.dispatchRequest(request, channel, new ThreadContext(Settings.EMPTY));
+        assertTrue(channel.sendResponseCalled.get());
+    }
+
+    public void testDispatchDoesNotRequireContentTypeForRequestsWithoutContent() {
+        FakeRestRequest fakeRestRequest = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY).build();
+        AssertingChannel channel = new AssertingChannel(fakeRestRequest, true, RestStatus.OK);
+
+        assertFalse(channel.sendResponseCalled.get());
+        restController.dispatchRequest(fakeRestRequest, channel, new ThreadContext(Settings.EMPTY));
+        assertTrue(channel.sendResponseCalled.get());
+    }
+
+    public void testDispatchWorksWithPlainText() {
+        String content = randomAsciiOfLengthBetween(1, BREAKER_LIMIT.bytesAsInt());
+        FakeRestRequest fakeRestRequest = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
+            .withContent(new BytesArray(content), null).withPath("/foo")
+            .withHeaders(Collections.singletonMap("Content-Type", Collections.singletonList("text/plain"))).build();
+        AssertingChannel channel = new AssertingChannel(fakeRestRequest, true, RestStatus.OK);
+        restController.registerHandler(RestRequest.Method.GET, "/foo", new RestHandler() {
+            @Override
+            public void handleRequest(RestRequest request, RestChannel channel, NodeClient client) throws Exception {
+                channel.sendResponse(new BytesRestResponse(RestStatus.OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
+            }
+
+            @Override
+            public boolean supportsPlainText() {
+                return true;
+            }
+        });
+
+        assertFalse(channel.sendResponseCalled.get());
+        restController.dispatchRequest(fakeRestRequest, channel, new ThreadContext(Settings.EMPTY));
+        assertTrue(channel.sendResponseCalled.get());
+        assertWarnings("Plain text request bodies are deprecated. Use request parameters or body in a supported format.");
+    }
+
+    public void testDispatchWorksWithAutoDetection() {
+        FakeRestRequest fakeRestRequest = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
+            .withContent(new BytesArray("{}"), null).withPath("/")
+            .withHeaders(Collections.singletonMap("Content-Type", Collections.singletonList("application/x-www-form-urlencoded"))).build();
+        AssertingChannel channel = new AssertingChannel(fakeRestRequest, true, RestStatus.OK);
+
+        assertFalse(channel.sendResponseCalled.get());
+        restController.dispatchRequest(fakeRestRequest, channel, new ThreadContext(Settings.EMPTY));
+        assertTrue(channel.sendResponseCalled.get());
+        assertWarnings("Content type detection for rest requests is deprecated. Specify the content type using the [Content-Type] header.");
+    }
+
     private static final class TestHttpServerTransport extends AbstractLifecycleComponent implements
         HttpServerTransport {
 
@@ -287,6 +347,7 @@ public class RestControllerTests extends ESTestCase {
 
     private static final class AssertingChannel extends AbstractRestChannel {
         private final RestStatus expectedStatus;
+        private final AtomicBoolean sendResponseCalled = new AtomicBoolean(false);
 
         protected AssertingChannel(RestRequest request, boolean detailedErrorsEnabled, RestStatus expectedStatus) {
             super(request, detailedErrorsEnabled);
@@ -296,6 +357,7 @@ public class RestControllerTests extends ESTestCase {
         @Override
         public void sendResponse(RestResponse response) {
             assertEquals(expectedStatus, response.status());
+            sendResponseCalled.set(true);
         }
     }
 
@@ -315,8 +377,9 @@ public class RestControllerTests extends ESTestCase {
 
         private final BytesReference content;
 
-        private TestRestRequest(String path, String content) {
-            super(NamedXContentRegistry.EMPTY, Collections.emptyMap(), path);
+        private TestRestRequest(String path, String content, XContentType xContentType) {
+            super(NamedXContentRegistry.EMPTY, Collections.emptyMap(), path, xContentType == null ?
+                Collections.emptyMap() : Collections.singletonMap("Content-Type", Collections.singletonList(xContentType.mediaType())));
             this.content = new BytesArray(content);
         }
 
@@ -340,15 +403,5 @@ public class RestControllerTests extends ESTestCase {
             return content;
         }
 
-        @Override
-        public String header(String name) {
-            return null;
-        }
-
-        @Override
-        public Iterable<Map.Entry<String, String>> headers() {
-            return null;
-        }
-
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/rest/RestRequestTests.java b/core/src/test/java/org/elasticsearch/rest/RestRequestTests.java
index 7f0184e20c..bddcd39160 100644
--- a/core/src/test/java/org/elasticsearch/rest/RestRequestTests.java
+++ b/core/src/test/java/org/elasticsearch/rest/RestRequestTests.java
@@ -24,11 +24,15 @@ import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static java.util.Collections.emptyMap;
@@ -54,10 +58,13 @@ public class RestRequestTests extends ESTestCase {
     }
 
     public void testContentOrSourceParam() throws IOException {
-        assertEquals(BytesArray.EMPTY, new ContentRestRequest("", emptyMap()).contentOrSourceParam());
-        assertEquals(new BytesArray("stuff"), new ContentRestRequest("stuff", emptyMap()).contentOrSourceParam());
-        assertEquals(new BytesArray("stuff"), new ContentRestRequest("stuff", singletonMap("source", "stuff2")).contentOrSourceParam());
-        assertEquals(new BytesArray("stuff"), new ContentRestRequest("", singletonMap("source", "stuff")).contentOrSourceParam());
+        assertEquals(BytesArray.EMPTY, new ContentRestRequest("", emptyMap()).contentOrSourceParam().v2());
+        assertEquals(new BytesArray("stuff"), new ContentRestRequest("stuff", emptyMap()).contentOrSourceParam().v2());
+        assertEquals(new BytesArray("stuff"),
+            new ContentRestRequest("stuff", singletonMap("source", "stuff2")).contentOrSourceParam().v2());
+        assertEquals(new BytesArray("{\"foo\": \"stuff\"}"),
+            new ContentRestRequest("", singletonMap("source", "{\"foo\": \"stuff\"}")).contentOrSourceParam().v2());
+        assertWarnings("Deprecated use of the [source] parameter without the [source_content_type] parameter.");
     }
 
     public void testHasContentOrSourceParam() throws IOException {
@@ -74,6 +81,7 @@ public class RestRequestTests extends ESTestCase {
         assertEquals(emptyMap(), new ContentRestRequest("{}", emptyMap()).contentOrSourceParamParser().map());
         assertEquals(emptyMap(), new ContentRestRequest("{}", singletonMap("source", "stuff2")).contentOrSourceParamParser().map());
         assertEquals(emptyMap(), new ContentRestRequest("", singletonMap("source", "{}")).contentOrSourceParamParser().map());
+        assertWarnings("Deprecated use of the [source] parameter without the [source_content_type] parameter.");
     }
 
     public void testWithContentOrSourceParamParserOrNull() throws IOException {
@@ -83,12 +91,58 @@ public class RestRequestTests extends ESTestCase {
                 assertEquals(emptyMap(), parser.map()));
         new ContentRestRequest("", singletonMap("source", "{}")).withContentOrSourceParamParserOrNull(parser ->
                 assertEquals(emptyMap(), parser.map()));
+        assertWarnings("Deprecated use of the [source] parameter without the [source_content_type] parameter.");
+    }
+
+    public void testContentTypeParsing() {
+        for (XContentType xContentType : XContentType.values()) {
+            Map<String, List<String>> map = new HashMap<>();
+            map.put("Content-Type", Collections.singletonList(xContentType.mediaType()));
+            ContentRestRequest restRequest = new ContentRestRequest("", Collections.emptyMap(), map);
+            assertEquals(xContentType, restRequest.getXContentType());
+
+            map = new HashMap<>();
+            map.put("Content-Type", Collections.singletonList(xContentType.mediaTypeWithoutParameters()));
+            restRequest = new ContentRestRequest("", Collections.emptyMap(), map);
+            assertEquals(xContentType, restRequest.getXContentType());
+        }
+    }
+
+    public void testPlainTextSupport() {
+        ContentRestRequest restRequest = new ContentRestRequest(randomAsciiOfLengthBetween(1, 30), Collections.emptyMap(),
+            Collections.singletonMap("Content-Type",
+                Collections.singletonList(randomFrom("text/plain", "text/plain; charset=utf-8", "text/plain;charset=utf-8"))));
+        assertNull(restRequest.getXContentType());
+    }
+
+    public void testMalformedContentTypeHeader() {
+        final String type = randomFrom("text", "text/:ain; charset=utf-8", "text/plain\";charset=utf-8", ":", "/", "t:/plain");
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new ContentRestRequest("", Collections.emptyMap(),
+            Collections.singletonMap("Content-Type", Collections.singletonList(type))));
+        assertEquals("invalid Content-Type header [" + type + "]", e.getMessage());
+    }
+
+    public void testNoContentTypeHeader() {
+        ContentRestRequest contentRestRequest = new ContentRestRequest("", Collections.emptyMap(), Collections.emptyMap());
+        assertNull(contentRestRequest.getXContentType());
+    }
+
+    public void testMultipleContentTypeHeaders() {
+        List<String> headers = new ArrayList<>(randomUnique(() -> randomAsciiOfLengthBetween(1, 16), randomIntBetween(2, 10)));
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> new ContentRestRequest("", Collections.emptyMap(),
+            Collections.singletonMap("Content-Type", headers)));
+        assertEquals("only one Content-Type header should be provided", e.getMessage());
     }
 
     private static final class ContentRestRequest extends RestRequest {
         private final BytesArray content;
-        public ContentRestRequest(String content, Map<String, String> params) {
-            super(NamedXContentRegistry.EMPTY, params, "not used by this test");
+
+        ContentRestRequest(String content, Map<String, String> params) {
+            this(content, params, Collections.singletonMap("Content-Type", Collections.singletonList("application/json")));
+        }
+
+        ContentRestRequest(String content, Map<String, String> params, Map<String, List<String>> headers) {
+            super(NamedXContentRegistry.EMPTY, params, "not used by this test", headers);
             this.content = new BytesArray(content);
         }
 
@@ -96,7 +150,7 @@ public class RestRequestTests extends ESTestCase {
         public boolean hasContent() {
             return Strings.hasLength(content);
         }
-        
+
         @Override
         public BytesReference content() {
             return content;
@@ -111,15 +165,5 @@ public class RestRequestTests extends ESTestCase {
         public Method method() {
             throw new UnsupportedOperationException("Not used by this test");
         }
-
-        @Override
-        public Iterable<Entry<String, String>> headers() {
-            throw new UnsupportedOperationException("Not used by this test");
-        }
-
-        @Override
-        public String header(String name) {
-            throw new UnsupportedOperationException("Not used by this test");
-        }
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/rest/action/admin/indices/RestAnalyzeActionTests.java b/core/src/test/java/org/elasticsearch/rest/action/admin/indices/RestAnalyzeActionTests.java
index da52358d3c..958b9e5222 100644
--- a/core/src/test/java/org/elasticsearch/rest/action/admin/indices/RestAnalyzeActionTests.java
+++ b/core/src/test/java/org/elasticsearch/rest/action/admin/indices/RestAnalyzeActionTests.java
@@ -23,6 +23,7 @@ import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.test.ESTestCase;
@@ -92,7 +93,8 @@ public class RestAnalyzeActionTests extends ESTestCase {
 
     public void testParseXContentForAnalyzeRequestWithInvalidJsonThrowsException() throws Exception {
         RestAnalyzeAction action = new RestAnalyzeAction(Settings.EMPTY, mock(RestController.class));
-        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray("{invalid_json}")).build();
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry())
+            .withContent(new BytesArray("{invalid_json}"), XContentType.JSON).build();
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> action.handleRequest(request, null, null));
         assertThat(e.getMessage(), equalTo("Failed to parse request body"));
     }
diff --git a/core/src/test/java/org/elasticsearch/rest/action/cat/RestTableTests.java b/core/src/test/java/org/elasticsearch/rest/action/cat/RestTableTests.java
index 38ed76cae5..4f7bc1bedd 100644
--- a/core/src/test/java/org/elasticsearch/rest/action/cat/RestTableTests.java
+++ b/core/src/test/java/org/elasticsearch/rest/action/cat/RestTableTests.java
@@ -104,35 +104,35 @@ public class RestTableTests extends ESTestCase {
     }
 
     public void testThatWeUseTheAcceptHeaderJson() throws Exception {
-        assertResponse(Collections.singletonMap(ACCEPT, APPLICATION_JSON),
+        assertResponse(Collections.singletonMap(ACCEPT, Collections.singletonList(APPLICATION_JSON)),
                 APPLICATION_JSON,
                 JSON_TABLE_BODY);
     }
 
     public void testThatWeUseTheAcceptHeaderYaml() throws Exception {
-        assertResponse(Collections.singletonMap(ACCEPT, APPLICATION_YAML),
+        assertResponse(Collections.singletonMap(ACCEPT, Collections.singletonList(APPLICATION_YAML)),
                 APPLICATION_YAML,
                 YAML_TABLE_BODY);
     }
 
     public void testThatWeUseTheAcceptHeaderSmile() throws Exception {
-        assertResponseContentType(Collections.singletonMap(ACCEPT, APPLICATION_SMILE),
+        assertResponseContentType(Collections.singletonMap(ACCEPT, Collections.singletonList(APPLICATION_SMILE)),
                 APPLICATION_SMILE);
     }
 
     public void testThatWeUseTheAcceptHeaderCbor() throws Exception {
-        assertResponseContentType(Collections.singletonMap(ACCEPT, APPLICATION_CBOR),
+        assertResponseContentType(Collections.singletonMap(ACCEPT, Collections.singletonList(APPLICATION_CBOR)),
                 APPLICATION_CBOR);
     }
 
     public void testThatWeUseTheAcceptHeaderText() throws Exception {
-        assertResponse(Collections.singletonMap(ACCEPT, TEXT_PLAIN),
+        assertResponse(Collections.singletonMap(ACCEPT, Collections.singletonList(TEXT_PLAIN)),
                 TEXT_PLAIN,
                 TEXT_TABLE_BODY);
     }
 
     public void testIgnoreContentType() throws Exception {
-        assertResponse(Collections.singletonMap(CONTENT_TYPE, APPLICATION_JSON),
+        assertResponse(Collections.singletonMap(CONTENT_TYPE, Collections.singletonList(APPLICATION_JSON)),
                 TEXT_PLAIN,
                 TEXT_TABLE_BODY);
     }
@@ -252,7 +252,7 @@ public class RestTableTests extends ESTestCase {
         assertEquals(Arrays.asList(1,0,2), rowOrder);
     }
 
-    private RestResponse assertResponseContentType(Map<String, String> headers, String mediaType) throws Exception {
+    private RestResponse assertResponseContentType(Map<String, List<String>> headers, String mediaType) throws Exception {
         FakeRestRequest requestWithAcceptHeader = new FakeRestRequest.Builder(xContentRegistry()).withHeaders(headers).build();
         table.startRow();
         table.addCell("foo");
@@ -274,7 +274,7 @@ public class RestTableTests extends ESTestCase {
         return response;
     }
 
-    private void assertResponse(Map<String, String> headers, String mediaType, String body) throws Exception {
+    private void assertResponse(Map<String, List<String>> headers, String mediaType, String body) throws Exception {
         RestResponse response = assertResponseContentType(headers, mediaType);
         assertThat(response.content().utf8ToString(), equalTo(body));
     }
diff --git a/core/src/test/java/org/elasticsearch/routing/AliasRoutingIT.java b/core/src/test/java/org/elasticsearch/routing/AliasRoutingIT.java
index 621ade9e31..dc8b6b5446 100644
--- a/core/src/test/java/org/elasticsearch/routing/AliasRoutingIT.java
+++ b/core/src/test/java/org/elasticsearch/routing/AliasRoutingIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.admin.indices.alias.IndicesAliasesRequest.AliasA
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -64,7 +65,7 @@ public class AliasRoutingIT extends ESIntegTestCase {
         logger.info("--> updating with id [1] and routing through alias");
         client().prepareUpdate("alias0", "type1", "1")
                 .setUpsert(XContentFactory.jsonBuilder().startObject().field("field", 1).endObject())
-                .setDoc("field", "value2")
+                .setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
                 .execute().actionGet();
         for (int i = 0; i < 5; i++) {
             assertThat(client().prepareGet("alias0", "type1", "1").execute().actionGet().isExists(), equalTo(true));
diff --git a/core/src/test/java/org/elasticsearch/routing/SimpleRoutingIT.java b/core/src/test/java/org/elasticsearch/routing/SimpleRoutingIT.java
index 2490134db4..b027a13e86 100644
--- a/core/src/test/java/org/elasticsearch/routing/SimpleRoutingIT.java
+++ b/core/src/test/java/org/elasticsearch/routing/SimpleRoutingIT.java
@@ -207,13 +207,13 @@ public class SimpleRoutingIT extends ESIntegTestCase {
         }
 
         try {
-            client().prepareUpdate(indexOrAlias(), "type1", "1").setDoc("field", "value2").execute().actionGet();
+            client().prepareUpdate(indexOrAlias(), "type1", "1").setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2").execute().actionGet();
             fail("update with missing routing when routing is required should fail");
         } catch(ElasticsearchException e) {
             assertThat(e.unwrapCause(), instanceOf(RoutingMissingException.class));
         }
 
-        client().prepareUpdate(indexOrAlias(), "type1", "1").setRouting("0").setDoc("field", "value2").execute().actionGet();
+        client().prepareUpdate(indexOrAlias(), "type1", "1").setRouting("0").setDoc(Requests.INDEX_CONTENT_TYPE, "field", "value2").get();
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         for (int i = 0; i < 5; i++) {
@@ -254,7 +254,7 @@ public class SimpleRoutingIT extends ESIntegTestCase {
 
         {
             BulkResponse bulkResponse = client().prepareBulk().add(Requests.indexRequest(indexOrAlias()).type("type1").id("1")
-                .source("field", "value")).execute().actionGet();
+                .source(Requests.INDEX_CONTENT_TYPE, "field", "value")).execute().actionGet();
             assertThat(bulkResponse.getItems().length, equalTo(1));
             assertThat(bulkResponse.hasFailures(), equalTo(true));
 
@@ -269,12 +269,13 @@ public class SimpleRoutingIT extends ESIntegTestCase {
 
         {
             BulkResponse bulkResponse = client().prepareBulk().add(Requests.indexRequest(indexOrAlias()).type("type1").id("1").routing("0")
-                .source("field", "value")).execute().actionGet();
+                .source(Requests.INDEX_CONTENT_TYPE, "field", "value")).execute().actionGet();
             assertThat(bulkResponse.hasFailures(), equalTo(false));
         }
 
         {
-            BulkResponse bulkResponse = client().prepareBulk().add(new UpdateRequest(indexOrAlias(), "type1", "1").doc("field", "value2"))
+            BulkResponse bulkResponse = client().prepareBulk().add(new UpdateRequest(indexOrAlias(), "type1", "1")
+                .doc(Requests.INDEX_CONTENT_TYPE, "field", "value2"))
                 .execute().actionGet();
             assertThat(bulkResponse.getItems().length, equalTo(1));
             assertThat(bulkResponse.hasFailures(), equalTo(true));
@@ -289,7 +290,8 @@ public class SimpleRoutingIT extends ESIntegTestCase {
         }
 
         {
-            BulkResponse bulkResponse = client().prepareBulk().add(new UpdateRequest(indexOrAlias(), "type1", "1").doc("field", "value2")
+            BulkResponse bulkResponse = client().prepareBulk().add(new UpdateRequest(indexOrAlias(), "type1", "1")
+                .doc(Requests.INDEX_CONTENT_TYPE, "field", "value2")
                 .routing("0")).execute().actionGet();
             assertThat(bulkResponse.hasFailures(), equalTo(false));
         }
@@ -369,12 +371,12 @@ public class SimpleRoutingIT extends ESIntegTestCase {
         }
 
         UpdateResponse updateResponse = client().prepareUpdate(indexOrAlias(), "type1", "1").setRouting("0")
-                .setDoc("field1", "value1").get();
+                .setDoc(Requests.INDEX_CONTENT_TYPE, "field1", "value1").get();
         assertThat(updateResponse.getId(), equalTo("1"));
         assertThat(updateResponse.getVersion(), equalTo(2L));
 
         try {
-            client().prepareUpdate(indexOrAlias(), "type1", "1").setDoc("field1", "value1").get();
+            client().prepareUpdate(indexOrAlias(), "type1", "1").setDoc(Requests.INDEX_CONTENT_TYPE, "field1", "value1").get();
             fail();
         } catch (RoutingMissingException e) {
             assertThat(e.getMessage(), equalTo("routing is required for [test]/[type1]/[1]"));
diff --git a/core/src/test/java/org/elasticsearch/script/ScriptMetaDataTests.java b/core/src/test/java/org/elasticsearch/script/ScriptMetaDataTests.java
index e7365d667d..5a02ea1e96 100644
--- a/core/src/test/java/org/elasticsearch/script/ScriptMetaDataTests.java
+++ b/core/src/test/java/org/elasticsearch/script/ScriptMetaDataTests.java
@@ -38,23 +38,23 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
 
         XContentBuilder sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().startObject("template").field("field", "value").endObject().endObject();
-        builder.storeScript("template", StoredScriptSource.parse("lang", sourceBuilder.bytes()));
+        builder.storeScript("template", StoredScriptSource.parse("lang", sourceBuilder.bytes(), sourceBuilder.contentType()));
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().field("template", "value").endObject();
-        builder.storeScript("template_field", StoredScriptSource.parse("lang", sourceBuilder.bytes()));
+        builder.storeScript("template_field", StoredScriptSource.parse("lang", sourceBuilder.bytes(), sourceBuilder.contentType()));
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().startObject("script").field("field", "value").endObject().endObject();
-        builder.storeScript("script", StoredScriptSource.parse("lang", sourceBuilder.bytes()));
+        builder.storeScript("script", StoredScriptSource.parse("lang", sourceBuilder.bytes(), sourceBuilder.contentType()));
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().field("script", "value").endObject();
-        builder.storeScript("script_field", StoredScriptSource.parse("lang", sourceBuilder.bytes()));
+        builder.storeScript("script_field", StoredScriptSource.parse("lang", sourceBuilder.bytes(), sourceBuilder.contentType()));
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().field("field", "value").endObject();
-        builder.storeScript("any", StoredScriptSource.parse("lang", sourceBuilder.bytes()));
+        builder.storeScript("any", StoredScriptSource.parse("lang", sourceBuilder.bytes(), sourceBuilder.contentType()));
 
         ScriptMetaData scriptMetaData = builder.build();
         assertEquals("{\"field\":\"value\"}", scriptMetaData.getStoredScript("template", "lang").getCode());
@@ -66,15 +66,15 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
 
     public void testDiff() throws Exception {
         ScriptMetaData.Builder builder = new ScriptMetaData.Builder(null);
-        builder.storeScript("1", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"abc\"}")));
-        builder.storeScript("2", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"def\"}")));
-        builder.storeScript("3", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"ghi\"}")));
+        builder.storeScript("1", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"abc\"}"), XContentType.JSON));
+        builder.storeScript("2", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"def\"}"), XContentType.JSON));
+        builder.storeScript("3", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"ghi\"}"), XContentType.JSON));
         ScriptMetaData scriptMetaData1 = builder.build();
 
         builder = new ScriptMetaData.Builder(scriptMetaData1);
-        builder.storeScript("2", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"changed\"}")));
+        builder.storeScript("2", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"changed\"}"), XContentType.JSON));
         builder.deleteScript("3", "lang");
-        builder.storeScript("4", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"jkl\"}")));
+        builder.storeScript("4", StoredScriptSource.parse("lang", new BytesArray("{\"foo\":\"jkl\"}"), XContentType.JSON));
         ScriptMetaData scriptMetaData2 = builder.build();
 
         ScriptMetaData.ScriptMetadataDiff diff = (ScriptMetaData.ScriptMetadataDiff) scriptMetaData2.diff(scriptMetaData1);
@@ -93,7 +93,7 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
 
     public void testBuilder() {
         ScriptMetaData.Builder builder = new ScriptMetaData.Builder(null);
-        builder.storeScript("_id", StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"1 + 1\"}")));
+        builder.storeScript("_id", StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"1 + 1\"}"), XContentType.JSON));
 
         ScriptMetaData result = builder.build();
         assertEquals("1 + 1", result.getStoredScript("_id", "_lang").getCode());
@@ -106,7 +106,8 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
             String lang = randomAsciiOfLength(4);
             XContentBuilder sourceBuilder = XContentBuilder.builder(sourceContentType.xContent());
             sourceBuilder.startObject().field("script", randomAsciiOfLength(4)).endObject();
-            builder.storeScript(randomAsciiOfLength(i + 1), StoredScriptSource.parse(lang, sourceBuilder.bytes()));
+            builder.storeScript(randomAsciiOfLength(i + 1),
+                StoredScriptSource.parse(lang, sourceBuilder.bytes(), sourceBuilder.contentType()));
         }
         return builder.build();
     }
diff --git a/core/src/test/java/org/elasticsearch/script/ScriptServiceTests.java b/core/src/test/java/org/elasticsearch/script/ScriptServiceTests.java
index 71fdea972f..3482dc8bb3 100644
--- a/core/src/test/java/org/elasticsearch/script/ScriptServiceTests.java
+++ b/core/src/test/java/org/elasticsearch/script/ScriptServiceTests.java
@@ -30,6 +30,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.Streams;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.search.lookup.SearchLookup;
 import org.elasticsearch.test.ESTestCase;
@@ -413,14 +414,15 @@ public class ScriptServiceTests extends ESTestCase {
                     .field("script", "abc")
                 .endObject().bytes();
 
-        ScriptMetaData scriptMetaData = ScriptMetaData.putStoredScript(null, "_id", StoredScriptSource.parse("_lang", script));
+        ScriptMetaData scriptMetaData = ScriptMetaData.putStoredScript(null, "_id",
+            StoredScriptSource.parse("_lang", script, XContentType.JSON));
         assertNotNull(scriptMetaData);
         assertEquals("abc", scriptMetaData.getStoredScript("_id", "_lang").getCode());
     }
 
     public void testDeleteScript() throws Exception {
         ScriptMetaData scriptMetaData = ScriptMetaData.putStoredScript(null, "_id",
-            StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"abc\"}")));
+            StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"abc\"}"), XContentType.JSON));
         scriptMetaData = ScriptMetaData.deleteStoredScript(scriptMetaData, "_id", "_lang");
         assertNotNull(scriptMetaData);
         assertNull(scriptMetaData.getStoredScript("_id", "_lang"));
@@ -438,7 +440,7 @@ public class ScriptServiceTests extends ESTestCase {
             .metaData(MetaData.builder()
                 .putCustom(ScriptMetaData.TYPE,
                     new ScriptMetaData.Builder(null).storeScript("_id",
-                        StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"abc\"}"))).build()))
+                        StoredScriptSource.parse("_lang", new BytesArray("{\"script\":\"abc\"}"), XContentType.JSON)).build()))
             .build();
 
         assertEquals("abc", scriptService.getStoredScript(cs, new GetStoredScriptRequest("_id", "_lang")).getCode());
diff --git a/core/src/test/java/org/elasticsearch/script/StoredScriptTests.java b/core/src/test/java/org/elasticsearch/script/StoredScriptTests.java
index 8a6d54c0b9..5f000f28cb 100644
--- a/core/src/test/java/org/elasticsearch/script/StoredScriptTests.java
+++ b/core/src/test/java/org/elasticsearch/script/StoredScriptTests.java
@@ -187,7 +187,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
         try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
             builder.startObject().field("script", "code").endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
@@ -197,7 +197,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
         try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
             builder.startObject().field("template", "code").endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code",
                 Collections.singletonMap(Script.CONTENT_TYPE_OPTION, builder.contentType().mediaType()));
 
@@ -213,7 +213,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 code = cb.startObject().field("query", "code").endObject().string();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", code,
                 Collections.singletonMap(Script.CONTENT_TYPE_OPTION, builder.contentType().mediaType()));
 
@@ -229,7 +229,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 code = cb.startObject().field("query", "code").endObject().string();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", code,
                 Collections.singletonMap(Script.CONTENT_TYPE_OPTION, builder.contentType().mediaType()));
 
@@ -245,7 +245,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 code = cb.startObject().field("query", "code").endObject().string();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse("lang", builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", code,
                 Collections.singletonMap(Script.CONTENT_TYPE_OPTION, builder.contentType().mediaType()));
 
@@ -256,7 +256,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
         try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {
             builder.startObject().field("script").startObject().field("lang", "lang").field("code", "code").endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
@@ -267,7 +267,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             builder.startObject().field("script").startObject().field("lang", "lang").field("code", "code")
                 .field("options").startObject().endObject().endObject().endObject();
 
-            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
@@ -283,7 +283,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 code = cb.startObject().field("query", "code").endObject().string();
             }
 
-            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes());
+            StoredScriptSource parsed = StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON);
             StoredScriptSource source = new StoredScriptSource("lang", code,
                 Collections.singletonMap(Script.CONTENT_TYPE_OPTION, builder.contentType().mediaType()));
 
@@ -297,7 +297,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             builder.startObject().field("template", "code").endObject();
 
             IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () ->
-                StoredScriptSource.parse(null, builder.bytes()));
+                StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON));
             assertThat(iae.getMessage(), equalTo("unexpected stored script format"));
         }
 
@@ -306,7 +306,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             builder.startObject().field("script").startObject().field("code", "code").endObject().endObject();
 
             IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () ->
-                StoredScriptSource.parse(null, builder.bytes()));
+                StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON));
             assertThat(iae.getMessage(), equalTo("must specify lang for stored script"));
         }
 
@@ -315,7 +315,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             builder.startObject().field("script").startObject().field("lang", "lang").endObject().endObject();
 
             IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () ->
-                StoredScriptSource.parse(null, builder.bytes()));
+                StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON));
             assertThat(iae.getMessage(), equalTo("must specify code for stored script"));
         }
 
@@ -325,7 +325,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 .startObject("options").field("option", "option").endObject().endObject().endObject();
 
             IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () ->
-                StoredScriptSource.parse(null, builder.bytes()));
+                StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON));
             assertThat(iae.getMessage(), equalTo("illegal compiler options [{option=option}] specified"));
         }
 
@@ -335,7 +335,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
                 .startObject("options").field("content_type", "option").endObject().endObject().endObject();
 
             ParsingException pe = expectThrows(ParsingException.class, () ->
-                StoredScriptSource.parse(null, builder.bytes()));
+                StoredScriptSource.parse(null, builder.bytes(), XContentType.JSON));
             assertThat(pe.getRootCause().getMessage(), equalTo("content_type cannot be user-specified"));
         }
     }
diff --git a/core/src/test/java/org/elasticsearch/script/StoredScriptsIT.java b/core/src/test/java/org/elasticsearch/script/StoredScriptsIT.java
index 106cb82526..f5c70edb02 100644
--- a/core/src/test/java/org/elasticsearch/script/StoredScriptsIT.java
+++ b/core/src/test/java/org/elasticsearch/script/StoredScriptsIT.java
@@ -20,6 +20,7 @@ package org.elasticsearch.script;
 
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -52,7 +53,7 @@ public class StoredScriptsIT extends ESIntegTestCase {
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(LANG)
                 .setId("foobar")
-                .setContent(new BytesArray("{\"script\":\"1\"}")));
+                .setContent(new BytesArray("{\"script\":\"1\"}"), XContentType.JSON));
         String script = client().admin().cluster().prepareGetStoredScript(LANG, "foobar")
                 .get().getSource().getCode();
         assertNotNull(script);
@@ -68,7 +69,7 @@ public class StoredScriptsIT extends ESIntegTestCase {
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> client().admin().cluster().preparePutStoredScript()
                 .setLang("lang#")
                 .setId("id#")
-                .setContent(new BytesArray("{}"))
+                .setContent(new BytesArray("{}"), XContentType.JSON)
                 .get());
         assertEquals("Validation Failed: 1: id cannot contain '#' for stored script;" +
             "2: lang cannot contain '#' for stored script;", e.getMessage());
@@ -78,7 +79,7 @@ public class StoredScriptsIT extends ESIntegTestCase {
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> client().admin().cluster().preparePutStoredScript()
                 .setLang(LANG)
                 .setId("foobar")
-                .setContent(new BytesArray(randomAsciiOfLength(SCRIPT_MAX_SIZE_IN_BYTES + 1)))
+                .setContent(new BytesArray(randomAsciiOfLength(SCRIPT_MAX_SIZE_IN_BYTES + 1)), XContentType.JSON)
                 .get()
         );
         assertEquals("exceeded max allowed stored script size in bytes [64] with size [65] for script [foobar]", e.getMessage());
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ChildrenIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ChildrenIT.java
index d57e2774b5..2268826100 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ChildrenIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/ChildrenIT.java
@@ -22,8 +22,10 @@ import org.apache.lucene.search.join.ScoreMode;
 import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.update.UpdateResponse;
+import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.aggregations.AggregationBuilders;
 import org.elasticsearch.search.aggregations.bucket.children.Children;
@@ -121,8 +123,8 @@ public class ChildrenIT extends ESIntegTestCase {
         requests.add(client().prepareIndex("test", "article", "b").setSource("category", new String[]{"a", "b"}, "randomized", false));
         requests.add(client().prepareIndex("test", "article", "c").setSource("category", new String[]{"a", "b", "c"}, "randomized", false));
         requests.add(client().prepareIndex("test", "article", "d").setSource("category", new String[]{"c"}, "randomized", false));
-        requests.add(client().prepareIndex("test", "comment", "a").setParent("a").setSource("{}"));
-        requests.add(client().prepareIndex("test", "comment", "c").setParent("c").setSource("{}"));
+        requests.add(client().prepareIndex("test", "comment", "a").setParent("a").setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("test", "comment", "c").setParent("c").setSource("{}", XContentType.JSON));
 
         indexRandom(true, requests);
         ensureSearchable("test");
@@ -240,7 +242,7 @@ public class ChildrenIT extends ESIntegTestCase {
         );
 
         List<IndexRequestBuilder> requests = new ArrayList<>();
-        requests.add(client().prepareIndex(indexName, "parent", "1").setSource("{}"));
+        requests.add(client().prepareIndex(indexName, "parent", "1").setSource("{}", XContentType.JSON));
         requests.add(client().prepareIndex(indexName, "child", "0").setParent("1").setSource("count", 1));
         requests.add(client().prepareIndex(indexName, "child", "1").setParent("1").setSource("count", 1));
         requests.add(client().prepareIndex(indexName, "child", "2").setParent("1").setSource("count", 1));
@@ -267,7 +269,7 @@ public class ChildrenIT extends ESIntegTestCase {
              */
             UpdateResponse updateResponse = client().prepareUpdate(indexName, "child", idToUpdate)
                     .setParent("1")
-                    .setDoc("count", 1)
+                    .setDoc(Requests.INDEX_CONTENT_TYPE, "count", 1)
                     .setDetectNoop(false)
                     .get();
             assertThat(updateResponse.getVersion(), greaterThan(1L));
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/NestedIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/NestedIT.java
index 51d702e354..522981b4f0 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/NestedIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/NestedIT.java
@@ -24,6 +24,7 @@ import org.elasticsearch.action.search.SearchPhaseExecutionException;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.search.aggregations.Aggregator.SubAggCollectionMode;
 import org.elasticsearch.search.aggregations.bucket.filter.Filter;
 import org.elasticsearch.search.aggregations.bucket.histogram.Histogram;
@@ -397,8 +398,8 @@ public class NestedIT extends ESIntegTestCase {
         ensureGreen("idx2");
 
         List<IndexRequestBuilder> indexRequests = new ArrayList<>(2);
-        indexRequests.add(client().prepareIndex("idx2", "provider", "1").setSource("{\"dates\": {\"month\": {\"label\": \"2014-11\", \"end\": \"2014-11-30\", \"start\": \"2014-11-01\"}, \"day\": \"2014-11-30\"}, \"comments\": [{\"cid\": 3,\"identifier\": \"29111\"}, {\"cid\": 4,\"tags\": [{\"tid\" :44,\"name\": \"Roles\"}], \"identifier\": \"29101\"}]}"));
-        indexRequests.add(client().prepareIndex("idx2", "provider", "2").setSource("{\"dates\": {\"month\": {\"label\": \"2014-12\", \"end\": \"2014-12-31\", \"start\": \"2014-12-01\"}, \"day\": \"2014-12-03\"}, \"comments\": [{\"cid\": 1, \"identifier\": \"29111\"}, {\"cid\": 2,\"tags\": [{\"tid\" : 22, \"name\": \"DataChannels\"}], \"identifier\": \"29101\"}]}"));
+        indexRequests.add(client().prepareIndex("idx2", "provider", "1").setSource("{\"dates\": {\"month\": {\"label\": \"2014-11\", \"end\": \"2014-11-30\", \"start\": \"2014-11-01\"}, \"day\": \"2014-11-30\"}, \"comments\": [{\"cid\": 3,\"identifier\": \"29111\"}, {\"cid\": 4,\"tags\": [{\"tid\" :44,\"name\": \"Roles\"}], \"identifier\": \"29101\"}]}", XContentType.JSON));
+        indexRequests.add(client().prepareIndex("idx2", "provider", "2").setSource("{\"dates\": {\"month\": {\"label\": \"2014-12\", \"end\": \"2014-12-31\", \"start\": \"2014-12-01\"}, \"day\": \"2014-12-03\"}, \"comments\": [{\"cid\": 1, \"identifier\": \"29111\"}, {\"cid\": 2,\"tags\": [{\"tid\" : 22, \"name\": \"DataChannels\"}], \"identifier\": \"29101\"}]}", XContentType.JSON));
         indexRandom(true, indexRequests);
 
         SearchResponse response = client().prepareSearch("idx2").setTypes("provider")
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
index c8cd235aed..4a8c88b309 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/SignificantTermsSignificanceScoreIT.java
@@ -25,6 +25,7 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.index.query.QueryParseContext;
 import org.elasticsearch.index.query.QueryShardException;
@@ -305,7 +306,7 @@ public class SignificantTermsSignificanceScoreIT extends ESIntegTestCase {
 
     public void testDeletesIssue7951() throws Exception {
         String settings = "{\"index.number_of_shards\": 1, \"index.number_of_replicas\": 0}";
-        assertAcked(prepareCreate(INDEX_NAME).setSettings(settings)
+        assertAcked(prepareCreate(INDEX_NAME).setSettings(settings, XContentType.JSON)
                 .addMapping("doc", "text", "type=keyword", CLASS_FIELD, "type=keyword"));
         String[] cat1v1 = {"constant", "one"};
         String[] cat1v2 = {"constant", "uno"};
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsShardMinDocCountIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
index 764ed3ba73..f7e3d9a61b 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/bucket/TermsShardMinDocCountIT.java
@@ -20,6 +20,7 @@ package org.elasticsearch.search.aggregations.bucket;
 
 import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.search.aggregations.bucket.filter.InternalFilter;
 import org.elasticsearch.search.aggregations.bucket.significant.SignificantTerms;
@@ -99,10 +100,10 @@ public class TermsShardMinDocCountIT extends ESIntegTestCase {
         String sourceClass = "{\"text\": \"" + term + "\", \"class\":" + "true" + "}";
         String sourceNotClass = "{\"text\": \"" + term + "\", \"class\":" + "false" + "}";
         for (int i = 0; i < numInClass; i++) {
-            builders.add(client().prepareIndex(index, type).setSource(sourceClass));
+            builders.add(client().prepareIndex(index, type).setSource(sourceClass, XContentType.JSON));
         }
         for (int i = 0; i < numNotInClass; i++) {
-            builders.add(client().prepareIndex(index, type).setSource(sourceNotClass));
+            builders.add(client().prepareIndex(index, type).setSource(sourceNotClass, XContentType.JSON));
         }
     }
 
@@ -152,7 +153,7 @@ public class TermsShardMinDocCountIT extends ESIntegTestCase {
     private void addTermsDocs(String term, int numDocs, List<IndexRequestBuilder> builders) {
         String sourceClass = "{\"text\": \"" + term + "\"}";
         for (int i = 0; i < numDocs; i++) {
-            builders.add(client().prepareIndex(index, type).setSource(sourceClass));
+            builders.add(client().prepareIndex(index, type).setSource(sourceClass, XContentType.JSON));
         }
 
     }
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java
index ca88b56cd4..f431cb0a47 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.plugins.Plugin;
@@ -230,22 +231,22 @@ public class ScriptedMetricIT extends ESIntegTestCase {
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(CustomScriptPlugin.NAME)
                 .setId("initScript_stored")
-                .setContent(new BytesArray("{\"script\":\"vars.multiplier = 3\"}")));
+                .setContent(new BytesArray("{\"script\":\"vars.multiplier = 3\"}"), XContentType.JSON));
 
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(CustomScriptPlugin.NAME)
                 .setId("mapScript_stored")
-                .setContent(new BytesArray("{\"script\":\"_agg.add(vars.multiplier)\"}")));
+                .setContent(new BytesArray("{\"script\":\"_agg.add(vars.multiplier)\"}"), XContentType.JSON));
 
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(CustomScriptPlugin.NAME)
                 .setId("combineScript_stored")
-                .setContent(new BytesArray("{\"script\":\"sum agg values as a new aggregation\"}")));
+                .setContent(new BytesArray("{\"script\":\"sum agg values as a new aggregation\"}"), XContentType.JSON));
 
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(CustomScriptPlugin.NAME)
                 .setId("reduceScript_stored")
-                .setContent(new BytesArray("{\"script\":\"sum aggs of agg values as a new aggregation\"}")));
+                .setContent(new BytesArray("{\"script\":\"sum aggs of agg values as a new aggregation\"}"), XContentType.JSON));
 
         indexRandom(true, builders);
         ensureSearchable();
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptIT.java
index e236845329..5b8ea2d5c6 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketScriptIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.MockScriptPlugin;
 import org.elasticsearch.script.Script;
@@ -482,7 +483,7 @@ public class BucketScriptIT extends ESIntegTestCase {
                 .setId("my_script")
                 .setLang(CustomScriptPlugin.NAME)
                 // Script source is not interpreted but it references a pre-defined script from CustomScriptPlugin
-                .setContent(new BytesArray("{ \"script\": \"my_script\" }")));
+                .setContent(new BytesArray("{ \"script\": \"my_script\" }"), XContentType.JSON));
 
         SearchResponse response = client()
                 .prepareSearch("idx")
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketSelectorIT.java b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketSelectorIT.java
index 689eafdf5a..68904c94ca 100644
--- a/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketSelectorIT.java
+++ b/core/src/test/java/org/elasticsearch/search/aggregations/pipeline/BucketSelectorIT.java
@@ -23,6 +23,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.MockScriptPlugin;
 import org.elasticsearch.script.Script;
@@ -434,7 +435,8 @@ public class BucketSelectorIT extends ESIntegTestCase {
                 .setId("my_script")
                 .setLang(CustomScriptPlugin.NAME)
                 // Source is not interpreted but my_script is defined in CustomScriptPlugin
-                .setContent(new BytesArray("{ \"script\": \"Double.isNaN(_value0) ? false : (_value0 + _value1 > 100)\" }")));
+                .setContent(new BytesArray("{ \"script\": \"Double.isNaN(_value0) ? false : (_value0 + _value1 > 100)\" }"),
+                    XContentType.JSON));
 
         Script script = new Script(ScriptType.STORED, CustomScriptPlugin.NAME, "my_script", Collections.emptyMap());
 
diff --git a/core/src/test/java/org/elasticsearch/search/builder/SearchSourceBuilderTests.java b/core/src/test/java/org/elasticsearch/search/builder/SearchSourceBuilderTests.java
index a4096c0e34..ef1750a448 100644
--- a/core/src/test/java/org/elasticsearch/search/builder/SearchSourceBuilderTests.java
+++ b/core/src/test/java/org/elasticsearch/search/builder/SearchSourceBuilderTests.java
@@ -280,7 +280,7 @@ public class SearchSourceBuilderTests extends AbstractSearchTestCase {
             XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
             searchSourceBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
             BytesReference source = builder.bytes();
-            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false).v2();
+            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false, xContentType).v2();
             assertEquals(0, sourceAsMap.size());
         }
         {
@@ -289,7 +289,7 @@ public class SearchSourceBuilderTests extends AbstractSearchTestCase {
             XContentBuilder builder = XContentFactory.contentBuilder(xContentType);
             searchSourceBuilder.toXContent(builder, ToXContent.EMPTY_PARAMS);
             BytesReference source = builder.bytes();
-            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false).v2();
+            Map<String, Object> sourceAsMap = XContentHelper.convertToMap(source, false, xContentType).v2();
             assertEquals(1, sourceAsMap.size());
             assertEquals("query", sourceAsMap.keySet().iterator().next());
         }
diff --git a/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java b/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
index 391d8be412..78cb846932 100644
--- a/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
+++ b/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.common.lucene.search.function.CombineFunction;
 import org.elasticsearch.common.lucene.search.function.FiltersFunctionScoreQuery;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.query.BoolQueryBuilder;
 import org.elasticsearch.index.query.HasChildQueryBuilder;
@@ -1009,7 +1010,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
                 .get();
         assertHitCount(response, 0L);
 
-        client().prepareIndex("test", "child", "c1").setSource("{}").setParent("p1").get();
+        client().prepareIndex("test", "child", "c1").setSource("{}", XContentType.JSON).setParent("p1").get();
         refresh();
 
         response = client().prepareSearch("test").setQuery(termQuery("_parent#parent", "p1")).get();
@@ -1018,7 +1019,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         response = client().prepareSearch("test").setQuery(queryStringQuery("_parent#parent:p1")).get();
         assertHitCount(response, 1L);
 
-        client().prepareIndex("test", "child", "c2").setSource("{}").setParent("p2").get();
+        client().prepareIndex("test", "child", "c2").setSource("{}", XContentType.JSON).setParent("p2").get();
         refresh();
         response = client().prepareSearch("test").setQuery(termsQuery("_parent#parent", "p1", "p2")).get();
         assertHitCount(response, 2L);
@@ -1039,13 +1040,13 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
             .addMapping("child", "_parent", "type=parent"));
         ensureGreen();
 
-        client().prepareIndex("test", "child", "c1").setSource("{}").setParent("p1").get();
+        client().prepareIndex("test", "child", "c1").setSource("{}", XContentType.JSON).setParent("p1").get();
         refresh();
 
         SearchResponse response = client().prepareSearch("test").setQuery(parentId("child", "p1")).get();
         assertHitCount(response, 1L);
 
-        client().prepareIndex("test", "child", "c2").setSource("{}").setParent("p2").get();
+        client().prepareIndex("test", "child", "c2").setSource("{}", XContentType.JSON).setParent("p2").get();
         refresh();
 
         response = client().prepareSearch("test")
@@ -1405,8 +1406,8 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
                 .addMapping("child", "_parent", "type=parent"));
         ensureGreen();
         for (int i = 0; i < 10; i++) {
-            client().prepareIndex("test", "parent", "p" + i).setSource("{}").get();
-            client().prepareIndex("test", "child", "c" + i).setSource("{}").setParent("p" + i).get();
+            client().prepareIndex("test", "parent", "p" + i).setSource("{}", XContentType.JSON).get();
+            client().prepareIndex("test", "child", "c" + i).setSource("{}", XContentType.JSON).setParent("p" + i).get();
         }
 
         refresh();
@@ -1488,8 +1489,8 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
 
         List<IndexRequestBuilder> indexRequests = new ArrayList<>();
         indexRequests.add(client().prepareIndex("test", "parent", "1").setSource("field1", "a"));
-        indexRequests.add(client().prepareIndex("test", "child", "1").setParent("1").setSource("{}"));
-        indexRequests.add(client().prepareIndex("test", "child", "2").setParent("1").setSource("{}"));
+        indexRequests.add(client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON));
+        indexRequests.add(client().prepareIndex("test", "child", "2").setParent("1").setSource("{}", XContentType.JSON));
         indexRandom(true, indexRequests);
 
         SearchResponse searchResponse = client().prepareSearch("test")
@@ -1883,8 +1884,8 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
 
     public void testParentFieldToNonExistingType() {
         assertAcked(prepareCreate("test").addMapping("parent").addMapping("child", "_parent", "type=parent2"));
-        client().prepareIndex("test", "parent", "1").setSource("{}").get();
-        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}").get();
+        client().prepareIndex("test", "parent", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON).get();
         refresh();
 
         try {
@@ -1898,8 +1899,8 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
 
     public void testHasParentInnerQueryType() {
         assertAcked(prepareCreate("test").addMapping("parent-type").addMapping("child-type", "_parent", "type=parent-type"));
-        client().prepareIndex("test", "child-type", "child-id").setParent("parent-id").setSource("{}").get();
-        client().prepareIndex("test", "parent-type", "parent-id").setSource("{}").get();
+        client().prepareIndex("test", "child-type", "child-id").setParent("parent-id").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "parent-type", "parent-id").setSource("{}", XContentType.JSON).get();
         refresh();
         //make sure that when we explicitly set a type, the inner query is executed in the context of the parent type instead
         SearchResponse searchResponse = client().prepareSearch("test").setTypes("child-type").setQuery(
@@ -1909,8 +1910,8 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
 
     public void testHasChildInnerQueryType() {
         assertAcked(prepareCreate("test").addMapping("parent-type").addMapping("child-type", "_parent", "type=parent-type"));
-        client().prepareIndex("test", "child-type", "child-id").setParent("parent-id").setSource("{}").get();
-        client().prepareIndex("test", "parent-type", "parent-id").setSource("{}").get();
+        client().prepareIndex("test", "child-type", "child-id").setParent("parent-id").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "parent-type", "parent-id").setSource("{}", XContentType.JSON).get();
         refresh();
         //make sure that when we explicitly set a type, the inner query is executed in the context of the child type instead
         SearchResponse searchResponse = client().prepareSearch("test").setTypes("parent-type").setQuery(
diff --git a/core/src/test/java/org/elasticsearch/search/child/ParentFieldLoadingIT.java b/core/src/test/java/org/elasticsearch/search/child/ParentFieldLoadingIT.java
index 5aead911ca..44b01b3a4b 100644
--- a/core/src/test/java/org/elasticsearch/search/child/ParentFieldLoadingIT.java
+++ b/core/src/test/java/org/elasticsearch/search/child/ParentFieldLoadingIT.java
@@ -26,6 +26,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.IndexSettings;
@@ -69,8 +70,8 @@ public class ParentFieldLoadingIT extends ESIntegTestCase {
                 .addMapping("child", childMapping(false)));
         ensureGreen();
 
-        client().prepareIndex("test", "parent", "1").setSource("{}").get();
-        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}").get();
+        client().prepareIndex("test", "parent", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON).get();
         refresh();
 
         ClusterStatsResponse response = client().admin().cluster().prepareClusterStats().get();
@@ -84,8 +85,8 @@ public class ParentFieldLoadingIT extends ESIntegTestCase {
                 .addMapping("child", "_parent", "type=parent"));
         ensureGreen();
 
-        client().prepareIndex("test", "parent", "1").setSource("{}").get();
-        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}").get();
+        client().prepareIndex("test", "parent", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON).get();
         refresh();
 
         response = client().admin().cluster().prepareClusterStats().get();
@@ -101,9 +102,9 @@ public class ParentFieldLoadingIT extends ESIntegTestCase {
 
         // Need to do 2 separate refreshes, otherwise we have 1 segment and then we can't measure if global ordinals
         // is loaded by the size of the field data cache, because global ordinals on 1 segment shards takes no extra memory.
-        client().prepareIndex("test", "parent", "1").setSource("{}").get();
+        client().prepareIndex("test", "parent", "1").setSource("{}", XContentType.JSON).get();
         refresh();
-        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}").get();
+        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON).get();
         refresh();
 
         response = client().admin().cluster().prepareClusterStats().get();
@@ -117,8 +118,8 @@ public class ParentFieldLoadingIT extends ESIntegTestCase {
                 .addMapping("child", "_parent", "type=parent"));
         ensureGreen();
 
-        client().prepareIndex("test", "parent", "1").setSource("{}").get();
-        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}").get();
+        client().prepareIndex("test", "parent", "1").setSource("{}", XContentType.JSON).get();
+        client().prepareIndex("test", "child", "1").setParent("1").setSource("{}", XContentType.JSON).get();
         refresh();
 
         ClusterStatsResponse response = client().admin().cluster().prepareClusterStats().get();
@@ -153,7 +154,7 @@ public class ParentFieldLoadingIT extends ESIntegTestCase {
 
         // Need to add a new doc otherwise the refresh doesn't trigger a new searcher
         // Because it ends up in its own segment, but isn't of type parent or child, this doc doesn't contribute to the size of the fielddata cache
-        client().prepareIndex("test", "dummy", "dummy").setSource("{}").get();
+        client().prepareIndex("test", "dummy", "dummy").setSource("{}", XContentType.JSON).get();
         refresh();
         response = client().admin().cluster().prepareClusterStats().get();
         assertThat(response.getIndicesStats().getFieldData().getMemorySizeInBytes(), greaterThan(0L));
diff --git a/core/src/test/java/org/elasticsearch/search/fetch/subphase/InnerHitsIT.java b/core/src/test/java/org/elasticsearch/search/fetch/subphase/InnerHitsIT.java
index c008825222..1d24a1f16d 100644
--- a/core/src/test/java/org/elasticsearch/search/fetch/subphase/InnerHitsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/fetch/subphase/InnerHitsIT.java
@@ -25,6 +25,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.BoolQueryBuilder;
 import org.elasticsearch.index.query.InnerHitBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
@@ -331,19 +332,19 @@ public class InnerHitsIT extends ESIntegTestCase {
         int[] child2InnerObjects = new int[numDocs];
         for (int parent = 0; parent < numDocs; parent++) {
             String parentId = String.format(Locale.ENGLISH, "%03d", parent);
-            requestBuilders.add(client().prepareIndex("idx", "parent", parentId).setSource("{}"));
+            requestBuilders.add(client().prepareIndex("idx", "parent", parentId).setSource("{}", XContentType.JSON));
 
             int numChildDocs = child1InnerObjects[parent] = scaledRandomIntBetween(1, numDocs);
             int limit = child1 + numChildDocs;
             for (; child1 < limit; child1++) {
                 requestBuilders.add(client().prepareIndex("idx", "child1",
-                        String.format(Locale.ENGLISH, "%04d", child1)).setParent(parentId).setSource("{}"));
+                        String.format(Locale.ENGLISH, "%04d", child1)).setParent(parentId).setSource("{}", XContentType.JSON));
             }
             numChildDocs = child2InnerObjects[parent] = scaledRandomIntBetween(1, numDocs);
             limit = child2 + numChildDocs;
             for (; child2 < limit; child2++) {
                 requestBuilders.add(client().prepareIndex("idx", "child2",
-                        String.format(Locale.ENGLISH, "%04d", child2)).setParent(parentId).setSource("{}"));
+                        String.format(Locale.ENGLISH, "%04d", child2)).setParent(parentId).setSource("{}", XContentType.JSON));
             }
         }
         indexRandom(true, requestBuilders);
@@ -727,17 +728,26 @@ public class InnerHitsIT extends ESIntegTestCase {
         );
 
         List<IndexRequestBuilder> requests = new ArrayList<>();
-        requests.add(client().prepareIndex("royals", "king", "king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "prince", "prince").setParent("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "duke", "duke").setParent("prince").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "earl", "earl1").setParent("duke").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "earl", "earl2").setParent("duke").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "earl", "earl3").setParent("duke").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "earl", "earl4").setParent("duke").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "baron", "baron1").setParent("earl1").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "baron", "baron2").setParent("earl2").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "baron", "baron3").setParent("earl3").setRouting("king").setSource("{}"));
-        requests.add(client().prepareIndex("royals", "baron", "baron4").setParent("earl4").setRouting("king").setSource("{}"));
+        requests.add(client().prepareIndex("royals", "king", "king").setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "prince", "prince").setParent("king").setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "duke", "duke").setParent("prince").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "earl", "earl1").setParent("duke").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "earl", "earl2").setParent("duke").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "earl", "earl3").setParent("duke").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "earl", "earl4").setParent("duke").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "baron", "baron1").setParent("earl1").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "baron", "baron2").setParent("earl2").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "baron", "baron3").setParent("earl3").setRouting("king")
+            .setSource("{}", XContentType.JSON));
+        requests.add(client().prepareIndex("royals", "baron", "baron4").setParent("earl4").setRouting("king")
+            .setSource("{}", XContentType.JSON));
         indexRandom(true, requests);
 
         SearchResponse response = client().prepareSearch("royals")
@@ -899,10 +909,10 @@ public class InnerHitsIT extends ESIntegTestCase {
     public void testMatchesQueriesParentChildInnerHits() throws Exception {
         assertAcked(prepareCreate("index").addMapping("child", "_parent", "type=parent"));
         List<IndexRequestBuilder> requests = new ArrayList<>();
-        requests.add(client().prepareIndex("index", "parent", "1").setSource("{}"));
+        requests.add(client().prepareIndex("index", "parent", "1").setSource("{}", XContentType.JSON));
         requests.add(client().prepareIndex("index", "child", "1").setParent("1").setSource("field", "value1"));
         requests.add(client().prepareIndex("index", "child", "2").setParent("1").setSource("field", "value2"));
-        requests.add(client().prepareIndex("index", "parent", "2").setSource("{}"));
+        requests.add(client().prepareIndex("index", "parent", "2").setSource("{}", XContentType.JSON));
         requests.add(client().prepareIndex("index", "child", "3").setParent("2").setSource("field", "value1"));
         indexRandom(true, requests);
 
@@ -938,7 +948,7 @@ public class InnerHitsIT extends ESIntegTestCase {
     public void testDontExplode() throws Exception {
         assertAcked(prepareCreate("index1").addMapping("child", "_parent", "type=parent"));
         List<IndexRequestBuilder> requests = new ArrayList<>();
-        requests.add(client().prepareIndex("index1", "parent", "1").setSource("{}"));
+        requests.add(client().prepareIndex("index1", "parent", "1").setSource("{}", XContentType.JSON));
         requests.add(client().prepareIndex("index1", "child", "1").setParent("1").setSource("field", "value1"));
         indexRandom(true, requests);
 
@@ -1025,7 +1035,7 @@ public class InnerHitsIT extends ESIntegTestCase {
         );
         createIndex("index2");
         client().prepareIndex("index1", "parent_type", "1").setSource("nested_type", Collections.singletonMap("key", "value")).get();
-        client().prepareIndex("index1", "child_type", "2").setParent("1").setSource("{}").get();
+        client().prepareIndex("index1", "child_type", "2").setParent("1").setSource("{}", XContentType.JSON).get();
         client().prepareIndex("index2", "type", "3").setSource("key", "value").get();
         refresh();
 
diff --git a/core/src/test/java/org/elasticsearch/search/fields/SearchFieldsIT.java b/core/src/test/java/org/elasticsearch/search/fields/SearchFieldsIT.java
index 236d5ce1ab..a952ae8639 100644
--- a/core/src/test/java/org/elasticsearch/search/fields/SearchFieldsIT.java
+++ b/core/src/test/java/org/elasticsearch/search/fields/SearchFieldsIT.java
@@ -28,6 +28,7 @@ import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.joda.Joda;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.index.fielddata.ScriptDocValues;
 import org.elasticsearch.index.query.QueryBuilders;
@@ -689,8 +690,8 @@ public class SearchFieldsIT extends ESIntegTestCase {
                 .endArray()
                 .endObject().bytes();
 
-        client().prepareIndex("my-index", "my-type1", "1").setSource(source).get();
-        client().prepareIndex("my-index", "my-type2", "1").setRefreshPolicy(IMMEDIATE).setSource(source).get();
+        client().prepareIndex("my-index", "my-type1", "1").setSource(source, XContentType.JSON).get();
+        client().prepareIndex("my-index", "my-type2", "1").setRefreshPolicy(IMMEDIATE).setSource(source, XContentType.JSON).get();
 
 
         String field = "field1.field2.field3.field4";
diff --git a/core/src/test/java/org/elasticsearch/search/geo/GeoFilterIT.java b/core/src/test/java/org/elasticsearch/search/geo/GeoFilterIT.java
index 2707e3c0b2..568c723f8d 100644
--- a/core/src/test/java/org/elasticsearch/search/geo/GeoFilterIT.java
+++ b/core/src/test/java/org/elasticsearch/search/geo/GeoFilterIT.java
@@ -47,6 +47,7 @@ import org.elasticsearch.common.logging.ESLoggerFactory;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.search.SearchHit;
@@ -230,7 +231,7 @@ public class GeoFilterIT extends ESIntegTestCase {
                                 new CoordinatesBuilder().coordinate(-4, -4).coordinate(-4, 4).coordinate(4, 4).coordinate(4, -4).close()));
         BytesReference data = jsonBuilder().startObject().field("area", polygon).endObject().bytes();
 
-        client().prepareIndex("shapes", "polygon", "1").setSource(data).execute().actionGet();
+        client().prepareIndex("shapes", "polygon", "1").setSource(data, XContentType.JSON).execute().actionGet();
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         // Point in polygon
@@ -292,7 +293,7 @@ public class GeoFilterIT extends ESIntegTestCase {
                             new CoordinatesBuilder().coordinate(-4, -4).coordinate(-4, 4).coordinate(4, 4).coordinate(4, -4).close()));
 
         data = jsonBuilder().startObject().field("area", inverse).endObject().bytes();
-        client().prepareIndex("shapes", "polygon", "2").setSource(data).execute().actionGet();
+        client().prepareIndex("shapes", "polygon", "2").setSource(data, XContentType.JSON).execute().actionGet();
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         // re-check point on polygon hole
@@ -326,7 +327,7 @@ public class GeoFilterIT extends ESIntegTestCase {
                 .coordinate(170, -10).coordinate(190, -10).coordinate(190, 10).coordinate(170, 10).close());
 
         data = jsonBuilder().startObject().field("area", builder).endObject().bytes();
-        client().prepareIndex("shapes", "polygon", "1").setSource(data).execute().actionGet();
+        client().prepareIndex("shapes", "polygon", "1").setSource(data, XContentType.JSON).execute().actionGet();
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         // Create a polygon crossing longitude 180 with hole.
@@ -335,7 +336,7 @@ public class GeoFilterIT extends ESIntegTestCase {
                     .hole(new LineStringBuilder(new CoordinatesBuilder().coordinate(175, -5).coordinate(185, -5).coordinate(185, 5).coordinate(175, 5).close()));
 
         data = jsonBuilder().startObject().field("area", builder).endObject().bytes();
-        client().prepareIndex("shapes", "polygon", "1").setSource(data).execute().actionGet();
+        client().prepareIndex("shapes", "polygon", "1").setSource(data, XContentType.JSON).execute().actionGet();
         client().admin().indices().prepareRefresh().execute().actionGet();
 
         result = client().prepareSearch()
@@ -384,7 +385,7 @@ public class GeoFilterIT extends ESIntegTestCase {
 
         client().admin().indices().prepareCreate("countries").setSettings(settings)
                 .addMapping("country", xContentBuilder.string()).execute().actionGet();
-        BulkResponse bulk = client().prepareBulk().add(bulkAction, 0, bulkAction.length, null, null).execute().actionGet();
+        BulkResponse bulk = client().prepareBulk().add(bulkAction, 0, bulkAction.length, null, null, xContentBuilder.contentType()).get();
 
         for (BulkItemResponse item : bulk.getItems()) {
             assertFalse("unable to index data", item.isFailed());
diff --git a/core/src/test/java/org/elasticsearch/search/geo/GeoShapeQueryTests.java b/core/src/test/java/org/elasticsearch/search/geo/GeoShapeQueryTests.java
index 067c2dcac0..7e8aa1ad9d 100644
--- a/core/src/test/java/org/elasticsearch/search/geo/GeoShapeQueryTests.java
+++ b/core/src/test/java/org/elasticsearch/search/geo/GeoShapeQueryTests.java
@@ -21,6 +21,7 @@ package org.elasticsearch.search.geo;
 
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.locationtech.spatial4j.shape.Rectangle;
 import com.vividsolutions.jts.geom.Coordinate;
 
@@ -69,7 +70,8 @@ public class GeoShapeQueryTests extends ESSingleNodeTestCase {
         client().admin().indices().prepareCreate("test").addMapping("type1", mapping).execute().actionGet();
         ensureGreen();
 
-        client().prepareIndex("test", "type1", "aNullshape").setSource("{\"location\": null}").setRefreshPolicy(IMMEDIATE).get();
+        client().prepareIndex("test", "type1", "aNullshape").setSource("{\"location\": null}", XContentType.JSON)
+            .setRefreshPolicy(IMMEDIATE).get();
         GetResponse result = client().prepareGet("test", "type1", "aNullshape").execute().actionGet();
         assertThat(result.getField("location"), nullValue());
     }
@@ -252,8 +254,8 @@ public class GeoShapeQueryTests extends ESSingleNodeTestCase {
                 .setSource(
                         String.format(
                                 Locale.ROOT, "{ %s, \"1\" : { %s, \"2\" : { %s, \"3\" : { %s } }} }", location, location, location, location
-                        )
-                ).setRefreshPolicy(IMMEDIATE).get();
+                        ), XContentType.JSON)
+            .setRefreshPolicy(IMMEDIATE).get();
         client().prepareIndex("test", "type", "1")
                 .setSource(jsonBuilder().startObject().startObject("location")
                         .field("type", "polygon")
diff --git a/core/src/test/java/org/elasticsearch/search/msearch/MultiSearchIT.java b/core/src/test/java/org/elasticsearch/search/msearch/MultiSearchIT.java
index ccc3102f3a..c7e78f2cc2 100644
--- a/core/src/test/java/org/elasticsearch/search/msearch/MultiSearchIT.java
+++ b/core/src/test/java/org/elasticsearch/search/msearch/MultiSearchIT.java
@@ -21,6 +21,7 @@ package org.elasticsearch.search.msearch;
 
 import org.elasticsearch.action.search.MultiSearchRequest;
 import org.elasticsearch.action.search.MultiSearchResponse;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -59,7 +60,7 @@ public class MultiSearchIT extends ESIntegTestCase {
         createIndex("test");
         int numDocs = randomIntBetween(0, 16);
         for (int i = 0; i < numDocs; i++) {
-            client().prepareIndex("test", "type", Integer.toString(i)).setSource("{}").get();
+            client().prepareIndex("test", "type", Integer.toString(i)).setSource("{}", XContentType.JSON).get();
         }
         refresh();
 
diff --git a/core/src/test/java/org/elasticsearch/search/preference/SearchPreferenceIT.java b/core/src/test/java/org/elasticsearch/search/preference/SearchPreferenceIT.java
index 2914755ed7..4b3b890a20 100644
--- a/core/src/test/java/org/elasticsearch/search/preference/SearchPreferenceIT.java
+++ b/core/src/test/java/org/elasticsearch/search/preference/SearchPreferenceIT.java
@@ -27,6 +27,7 @@ import org.elasticsearch.client.Client;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.test.ESIntegTestCase;
 
@@ -98,7 +99,7 @@ public class SearchPreferenceIT extends ESIntegTestCase {
     }
 
     public void testSimplePreference() throws Exception {
-        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 1}").get();
+        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 1}", XContentType.JSON).get();
         ensureGreen();
 
         client().prepareIndex("test", "type1").setSource("field1", "value1").execute().actionGet();
@@ -131,7 +132,7 @@ public class SearchPreferenceIT extends ESIntegTestCase {
     }
 
     public void testReplicaPreference() throws Exception {
-        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 0}").get();
+        client().admin().indices().prepareCreate("test").setSettings("{\"number_of_replicas\": 0}", XContentType.JSON).get();
         ensureGreen();
 
         client().prepareIndex("test", "type1").setSource("field1", "value1").execute().actionGet();
@@ -147,7 +148,7 @@ public class SearchPreferenceIT extends ESIntegTestCase {
         SearchResponse resp = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_replica_first").execute().actionGet();
         assertThat(resp.getHits().totalHits(), equalTo(1L));
 
-        client().admin().indices().prepareUpdateSettings("test").setSettings("{\"number_of_replicas\": 1}").get();
+        client().admin().indices().prepareUpdateSettings("test").setSettings("{\"number_of_replicas\": 1}", XContentType.JSON).get();
         ensureGreen("test");
 
         resp = client().prepareSearch().setQuery(matchAllQuery()).setPreference("_replica").execute().actionGet();
diff --git a/core/src/test/java/org/elasticsearch/search/query/QueryStringIT.java b/core/src/test/java/org/elasticsearch/search/query/QueryStringIT.java
index 2fe14e4ee1..1dbeb24d4e 100644
--- a/core/src/test/java/org/elasticsearch/search/query/QueryStringIT.java
+++ b/core/src/test/java/org/elasticsearch/search/query/QueryStringIT.java
@@ -37,6 +37,7 @@ import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.Operator;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.index.query.QueryStringQueryBuilder;
@@ -64,7 +65,7 @@ public class QueryStringIT extends ESIntegTestCase {
     @Before
     public void setup() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/elasticsearch/search/query/all-query-index.json");
-        prepareCreate("test").setSource(indexBody).get();
+        prepareCreate("test").setSource(indexBody, XContentType.JSON).get();
         ensureGreen("test");
     }
 
@@ -151,7 +152,7 @@ public class QueryStringIT extends ESIntegTestCase {
     public void testDocWithAllTypes() throws Exception {
         List<IndexRequestBuilder> reqs = new ArrayList<>();
         String docBody = copyToStringFromClasspath("/org/elasticsearch/search/query/all-example-document.json");
-        reqs.add(client().prepareIndex("test", "doc", "1").setSource(docBody));
+        reqs.add(client().prepareIndex("test", "doc", "1").setSource(docBody, XContentType.JSON));
         indexRandom(true, false, reqs);
 
         SearchResponse resp = client().prepareSearch("test").setQuery(queryStringQuery("foo")).get();
@@ -214,7 +215,7 @@ public class QueryStringIT extends ESIntegTestCase {
 
     public void testExplicitAllFieldsRequested() throws Exception {
         String indexBody = copyToStringFromClasspath("/org/elasticsearch/search/query/all-query-index-with-all.json");
-        prepareCreate("test2").setSource(indexBody).get();
+        prepareCreate("test2").setSource(indexBody, XContentType.JSON).get();
         ensureGreen("test2");
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
diff --git a/core/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java b/core/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
index ebc2df30e1..7cb9627cf1 100644
--- a/core/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
+++ b/core/src/test/java/org/elasticsearch/search/query/SearchQueryIT.java
@@ -29,6 +29,7 @@ import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.BoolQueryBuilder;
 import org.elasticsearch.index.query.MatchQueryBuilder;
 import org.elasticsearch.index.query.MultiMatchQueryBuilder;
@@ -1796,8 +1797,8 @@ public class SearchQueryIT extends ESIntegTestCase {
     }
 
     public void testSearchEmptyDoc() {
-        assertAcked(prepareCreate("test").setSettings("{\"index.analysis.analyzer.default.type\":\"keyword\"}"));
-        client().prepareIndex("test", "type1", "1").setSource("{}").get();
+        assertAcked(prepareCreate("test").setSettings("{\"index.analysis.analyzer.default.type\":\"keyword\"}", XContentType.JSON));
+        client().prepareIndex("test", "type1", "1").setSource("{}", XContentType.JSON).get();
 
         refresh();
         assertHitCount(client().prepareSearch().setQuery(matchAllQuery()).get(), 1L);
diff --git a/core/src/test/java/org/elasticsearch/search/query/SimpleQueryStringIT.java b/core/src/test/java/org/elasticsearch/search/query/SimpleQueryStringIT.java
index 3ed464f312..1bec4bb20b 100644
--- a/core/src/test/java/org/elasticsearch/search/query/SimpleQueryStringIT.java
+++ b/core/src/test/java/org/elasticsearch/search/query/SimpleQueryStringIT.java
@@ -27,6 +27,7 @@ import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.BoolQueryBuilder;
 import org.elasticsearch.index.query.Operator;
 import org.elasticsearch.index.query.QueryBuilders;
@@ -471,7 +472,7 @@ public class SimpleQueryStringIT extends ESIntegTestCase {
 
         List<IndexRequestBuilder> reqs = new ArrayList<>();
         String docBody = copyToStringFromClasspath("/org/elasticsearch/search/query/all-example-document.json");
-        reqs.add(client().prepareIndex("test", "doc", "1").setSource(docBody));
+        reqs.add(client().prepareIndex("test", "doc", "1").setSource(docBody, XContentType.JSON));
         indexRandom(true, false, reqs);
 
         SearchResponse resp = client().prepareSearch("test").setQuery(simpleQueryStringQuery("foo")).get();
diff --git a/core/src/test/java/org/elasticsearch/search/scroll/RestClearScrollActionTests.java b/core/src/test/java/org/elasticsearch/search/scroll/RestClearScrollActionTests.java
index df89bda88d..ae8ad66ac8 100644
--- a/core/src/test/java/org/elasticsearch/search/scroll/RestClearScrollActionTests.java
+++ b/core/src/test/java/org/elasticsearch/search/scroll/RestClearScrollActionTests.java
@@ -24,6 +24,7 @@ import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.action.search.RestClearScrollAction;
@@ -48,7 +49,8 @@ public class RestClearScrollActionTests extends ESTestCase {
 
     public void testParseClearScrollRequestWithInvalidJsonThrowsException() throws Exception {
         RestClearScrollAction action = new RestClearScrollAction(Settings.EMPTY, mock(RestController.class));
-        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray("{invalid_json}")).build();
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry())
+            .withContent(new BytesArray("{invalid_json}"), XContentType.JSON).build();
         Exception e = expectThrows(IllegalArgumentException.class, () -> action.prepareRequest(request, null));
         assertThat(e.getMessage(), equalTo("Failed to parse request body"));
     }
diff --git a/core/src/test/java/org/elasticsearch/search/scroll/RestSearchScrollActionTests.java b/core/src/test/java/org/elasticsearch/search/scroll/RestSearchScrollActionTests.java
index 7d2a5024cc..662bc07f90 100644
--- a/core/src/test/java/org/elasticsearch/search/scroll/RestSearchScrollActionTests.java
+++ b/core/src/test/java/org/elasticsearch/search/scroll/RestSearchScrollActionTests.java
@@ -25,6 +25,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.action.search.RestSearchScrollAction;
@@ -52,7 +53,8 @@ public class RestSearchScrollActionTests extends ESTestCase {
 
     public void testParseSearchScrollRequestWithInvalidJsonThrowsException() throws Exception {
         RestSearchScrollAction action = new RestSearchScrollAction(Settings.EMPTY, mock(RestController.class));
-        RestRequest request = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray("{invalid_json}")).build();
+        RestRequest request = new FakeRestRequest.Builder(xContentRegistry())
+            .withContent(new BytesArray("{invalid_json}"), XContentType.JSON).build();
         Exception e = expectThrows(IllegalArgumentException.class, () -> action.prepareRequest(request, null));
         assertThat(e.getMessage(), equalTo("Failed to parse request body"));
     }
diff --git a/core/src/test/java/org/elasticsearch/search/scroll/SearchScrollIT.java b/core/src/test/java/org/elasticsearch/search/scroll/SearchScrollIT.java
index 3927d87912..1f368cb35d 100644
--- a/core/src/test/java/org/elasticsearch/search/scroll/SearchScrollIT.java
+++ b/core/src/test/java/org/elasticsearch/search/scroll/SearchScrollIT.java
@@ -521,7 +521,7 @@ public class SearchScrollIT extends ESIntegTestCase {
     private void assertToXContentResponse(ClearScrollResponse response, boolean succeed, int numFreed) throws IOException {
         XContentBuilder builder = XContentFactory.jsonBuilder();
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false).v2();
+        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
         assertThat(map.get("succeeded"), is(succeed));
         assertThat(map.get("num_freed"), equalTo(numFreed));
     }
diff --git a/core/src/test/java/org/elasticsearch/search/simple/SimpleSearchIT.java b/core/src/test/java/org/elasticsearch/search/simple/SimpleSearchIT.java
index 099cce038c..f63f13b6dd 100644
--- a/core/src/test/java/org/elasticsearch/search/simple/SimpleSearchIT.java
+++ b/core/src/test/java/org/elasticsearch/search/simple/SimpleSearchIT.java
@@ -26,6 +26,7 @@ import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.rest.RestStatus;
@@ -289,7 +290,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
 
     public void testInsaneFromAndSize() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertWindowFails(client().prepareSearch("idx").setFrom(Integer.MAX_VALUE));
         assertWindowFails(client().prepareSearch("idx").setSize(Integer.MAX_VALUE));
@@ -297,7 +298,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
 
     public void testTooLargeFromAndSize() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertWindowFails(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)));
         assertWindowFails(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1));
@@ -307,7 +308,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
 
     public void testLargeFromAndSizeSucceeds() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) - 10).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
@@ -318,7 +319,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
     public void testTooLargeFromAndSizeOkBySetting() throws Exception {
         prepareCreate("idx").setSettings(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(),
                 IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 2).get();
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1).get(), 1);
@@ -333,7 +334,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
                         Settings.builder().put(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(),
                                 IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 2))
                 .get());
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY)).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) + 1).get(), 1);
@@ -343,7 +344,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
 
     public void testTooLargeFromAndSizeBackwardsCompatibilityRecommendation() throws Exception {
         prepareCreate("idx").setSettings(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(), Integer.MAX_VALUE).get();
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(client().prepareSearch("idx").setFrom(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 10).get(), 1);
         assertHitCount(client().prepareSearch("idx").setSize(IndexSettings.MAX_RESULT_WINDOW_SETTING.get(Settings.EMPTY) * 10).get(), 1);
@@ -353,7 +354,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
 
     public void testTooLargeRescoreWindow() throws Exception {
         createIndex("idx");
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertRescoreWindowFails(Integer.MAX_VALUE);
         assertRescoreWindowFails(IndexSettings.MAX_RESCORE_WINDOW_SETTING.get(Settings.EMPTY) + 1);
@@ -363,7 +364,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
         int defaultMaxWindow = IndexSettings.MAX_RESCORE_WINDOW_SETTING.get(Settings.EMPTY);
         prepareCreate("idx").setSettings(IndexSettings.MAX_RESCORE_WINDOW_SETTING.getKey(),
                 defaultMaxWindow * 2).get();
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(
                 client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -374,7 +375,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
         int defaultMaxWindow = IndexSettings.MAX_RESCORE_WINDOW_SETTING.get(Settings.EMPTY);
         prepareCreate("idx").setSettings(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(), // Note that this is the RESULT window.
                 defaultMaxWindow * 2).get();
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(
                 client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -388,7 +389,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
                 .setSettings(
                         Settings.builder().put(IndexSettings.MAX_RESCORE_WINDOW_SETTING.getKey(), defaultMaxWindow * 2))
                 .get());
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(
                 client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
@@ -403,7 +404,7 @@ public class SimpleSearchIT extends ESIntegTestCase {
                         // Note that this is the RESULT window
                         Settings.builder().put(IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(), defaultMaxWindow * 2))
                 .get());
-        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}"));
+        indexRandom(true, client().prepareIndex("idx", "type").setSource("{}", XContentType.JSON));
 
         assertHitCount(
                 client().prepareSearch("idx").addRescorer(new QueryRescorerBuilder(matchAllQuery()).windowSize(defaultMaxWindow + 1)).get(),
diff --git a/core/src/test/java/org/elasticsearch/search/sort/FieldSortIT.java b/core/src/test/java/org/elasticsearch/search/sort/FieldSortIT.java
index 84dd3dabf6..7659576555 100644
--- a/core/src/test/java/org/elasticsearch/search/sort/FieldSortIT.java
+++ b/core/src/test/java/org/elasticsearch/search/sort/FieldSortIT.java
@@ -31,6 +31,7 @@ import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.Uid;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
@@ -91,7 +92,7 @@ public class FieldSortIT extends ESIntegTestCase {
                 assertAcked(prepareCreate("test_" + i).addAlias(new Alias("test")));
             }
             if (i > 0) {
-                client().prepareIndex("test_" + i, "foo", "" + i).setSource("{\"entry\": " + i + "}").get();
+                client().prepareIndex("test_" + i, "foo", "" + i).setSource("{\"entry\": " + i + "}", XContentType.JSON).get();
             }
         }
         refresh();
@@ -422,9 +423,9 @@ public class FieldSortIT extends ESIntegTestCase {
         assertAcked(client().admin().indices().prepareCreate("test")
                 .addMapping("type", "field1", "type=keyword").get());
 
-        client().prepareIndex("test", "post", "1").setSource("{\"field1\":\"value1\"}").execute().actionGet();
-        client().prepareIndex("test", "post", "2").setSource("{\"field1\":\"value2\"}").execute().actionGet();
-        client().prepareIndex("test", "post", "3").setSource("{\"field1\":\"value3\"}").execute().actionGet();
+        client().prepareIndex("test", "post", "1").setSource("{\"field1\":\"value1\"}", XContentType.JSON).execute().actionGet();
+        client().prepareIndex("test", "post", "2").setSource("{\"field1\":\"value2\"}", XContentType.JSON).execute().actionGet();
+        client().prepareIndex("test", "post", "3").setSource("{\"field1\":\"value3\"}", XContentType.JSON).execute().actionGet();
         refresh();
         SearchResponse result = client().prepareSearch("test").setQuery(matchAllQuery()).setTrackScores(true)
                 .addSort("field1", SortOrder.ASC).execute().actionGet();
diff --git a/core/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java b/core/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java
index 0000e73e27..6116cfa8b9 100644
--- a/core/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java
+++ b/core/src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreIT.java
@@ -65,6 +65,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.indices.IndicesService;
@@ -533,7 +534,7 @@ public class SharedClusterSnapshotRestoreIT extends AbstractSnapshotIntegTestCas
                 .endObject()
                 .endArray()
                 .endObject().bytes();
-            assertAcked(client().admin().cluster().preparePutPipeline("barbaz", pipelineSource).get());
+            assertAcked(client().admin().cluster().preparePutPipeline("barbaz", pipelineSource, XContentType.JSON).get());
         }
 
         if(testScript) {
@@ -541,7 +542,7 @@ public class SharedClusterSnapshotRestoreIT extends AbstractSnapshotIntegTestCas
             assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(MockScriptEngine.NAME)
                 .setId("foobar")
-                .setContent(new BytesArray("{\"script\":\"1\"}")));
+                .setContent(new BytesArray("{\"script\":\"1\"}"), XContentType.JSON));
         }
 
         logger.info("--> snapshot without global state");
diff --git a/core/src/test/java/org/elasticsearch/snapshots/SnapshotRequestsTests.java b/core/src/test/java/org/elasticsearch/snapshots/SnapshotRequestsTests.java
index cdacabdd66..a8e1eeaec1 100644
--- a/core/src/test/java/org/elasticsearch/snapshots/SnapshotRequestsTests.java
+++ b/core/src/test/java/org/elasticsearch/snapshots/SnapshotRequestsTests.java
@@ -79,7 +79,7 @@ public class SnapshotRequestsTests extends ESTestCase {
 
         BytesReference bytes = builder.endObject().bytes();
 
-        request.source(XContentHelper.convertToMap(bytes, true).v2());
+        request.source(XContentHelper.convertToMap(bytes, true, builder.contentType()).v2());
 
         assertEquals("test-repo", request.repository());
         assertEquals("test-snap", request.snapshot());
@@ -137,7 +137,7 @@ public class SnapshotRequestsTests extends ESTestCase {
 
         BytesReference bytes = builder.endObject().bytes();
 
-        request.source(XContentHelper.convertToMap(bytes, true).v2());
+        request.source(XContentHelper.convertToMap(bytes, true, builder.contentType()).v2());
 
         assertEquals("test-repo", request.repository());
         assertEquals("test-snap", request.snapshot());
diff --git a/core/src/test/java/org/elasticsearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java b/core/src/test/java/org/elasticsearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
index 7fc1490de7..6dd4fa384e 100644
--- a/core/src/test/java/org/elasticsearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
+++ b/core/src/test/java/org/elasticsearch/test/search/aggregations/bucket/SharedSignificantTermsTestMethods.java
@@ -21,6 +21,7 @@ package org.elasticsearch.test.search.aggregations.bucket;
 
 import org.elasticsearch.action.index.IndexRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.aggregations.bucket.significant.SignificantTerms;
 import org.elasticsearch.search.aggregations.bucket.terms.StringTerms;
@@ -80,7 +81,7 @@ public class SharedSignificantTermsTestMethods {
         if (type.equals("text")) {
             textMappings += ",fielddata=true";
         }
-        assertAcked(testCase.prepareCreate(INDEX_NAME).setSettings(settings)
+        assertAcked(testCase.prepareCreate(INDEX_NAME).setSettings(settings, XContentType.JSON)
                 .addMapping("doc", "text", textMappings, CLASS_FIELD, "type=keyword"));
         String[] gb = {"0", "1"};
         List<IndexRequestBuilder> indexRequestBuilderList = new ArrayList<>();
diff --git a/core/src/test/java/org/elasticsearch/threadpool/ThreadPoolSerializationTests.java b/core/src/test/java/org/elasticsearch/threadpool/ThreadPoolSerializationTests.java
index 01fc15e6f7..33047b2d12 100644
--- a/core/src/test/java/org/elasticsearch/threadpool/ThreadPoolSerializationTests.java
+++ b/core/src/test/java/org/elasticsearch/threadpool/ThreadPoolSerializationTests.java
@@ -78,7 +78,7 @@ public class ThreadPoolSerializationTests extends ESTestCase {
         info.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
 
-        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false).v2();
+        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
         assertThat(map, hasKey("foo"));
         map = (Map<String, Object>) map.get("foo");
         assertThat(map, hasKey("queue_size"));
@@ -100,7 +100,7 @@ public class ThreadPoolSerializationTests extends ESTestCase {
         info.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
 
-        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false).v2();
+        Map<String, Object> map = XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
         assertThat(map, hasKey("foo"));
         map = (Map<String, Object>) map.get("foo");
         assertThat(map, hasKey("queue_size"));
diff --git a/core/src/test/java/org/elasticsearch/update/UpdateIT.java b/core/src/test/java/org/elasticsearch/update/UpdateIT.java
index 2c98b39364..bc06582321 100644
--- a/core/src/test/java/org/elasticsearch/update/UpdateIT.java
+++ b/core/src/test/java/org/elasticsearch/update/UpdateIT.java
@@ -34,6 +34,7 @@ import org.elasticsearch.client.transport.NoNodeAvailableException;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.MergePolicyConfig;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.DocumentMissingException;
@@ -536,7 +537,7 @@ public class UpdateIT extends ESIntegTestCase {
         // With internal versions, tt means "if object is there with version X, update it or explode. If it is not there, index.
         client().prepareUpdate(indexOrAlias(), "type", "3")
                 .setScript(new Script(ScriptType.INLINE, "put_values", "", Collections.singletonMap("text", "v2")))
-                .setVersion(10).setUpsert("{ \"text\": \"v0\" }").get();
+                .setVersion(10).setUpsert("{ \"text\": \"v0\" }", XContentType.JSON).get();
         get = get("test", "type", "3");
         assertThat(get.getVersion(), equalTo(1L));
         assertThat((String) get.getSource().get("text"), equalTo("v0"));
diff --git a/core/src/test/java/org/elasticsearch/update/UpdateNoopIT.java b/core/src/test/java/org/elasticsearch/update/UpdateNoopIT.java
index f14d91465f..beab15165d 100644
--- a/core/src/test/java/org/elasticsearch/update/UpdateNoopIT.java
+++ b/core/src/test/java/org/elasticsearch/update/UpdateNoopIT.java
@@ -245,7 +245,7 @@ public class UpdateNoopIT extends ESIntegTestCase {
 
     private UpdateResponse update(Boolean detectNoop, long expectedVersion, XContentBuilder xContentBuilder) {
         UpdateRequestBuilder updateRequest = client().prepareUpdate("test", "type1", "1")
-                .setDoc(xContentBuilder.bytes().utf8ToString())
+                .setDoc(xContentBuilder)
                 .setDocAsUpsert(true)
                 .setFields("_source");
         if (detectNoop != null) {
diff --git a/distribution/integ-test-zip/src/test/java/org/elasticsearch/test/rest/CreatedLocationHeaderIT.java b/distribution/integ-test-zip/src/test/java/org/elasticsearch/test/rest/CreatedLocationHeaderIT.java
index 71ec194866..c61b736bf6 100644
--- a/distribution/integ-test-zip/src/test/java/org/elasticsearch/test/rest/CreatedLocationHeaderIT.java
+++ b/distribution/integ-test-zip/src/test/java/org/elasticsearch/test/rest/CreatedLocationHeaderIT.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.test.rest;
 
+import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.elasticsearch.client.Response;
 
@@ -47,12 +48,14 @@ public class CreatedLocationHeaderIT extends ESRestTestCase {
     public void testUpsert() throws IOException {
         locationTestCase(client().performRequest("POST", "test/test/1/_update", emptyMap(), new StringEntity("{"
                 + "\"doc\": {\"test\": \"test\"},"
-                + "\"doc_as_upsert\": true}")));
+                + "\"doc_as_upsert\": true}", ContentType.APPLICATION_JSON)));
     }
 
     private void locationTestCase(String method, String url) throws IOException {
-        locationTestCase(client().performRequest(method, url, emptyMap(), new StringEntity("{\"test\": \"test\"}")));
-        locationTestCase(client().performRequest(method, url + "?routing=cat", emptyMap(), new StringEntity("{\"test\": \"test\"}")));
+        locationTestCase(client().performRequest(method, url, emptyMap(),
+            new StringEntity("{\"test\": \"test\"}", ContentType.APPLICATION_JSON)));
+        locationTestCase(client().performRequest(method, url + "?routing=cat", emptyMap(),
+            new StringEntity("{\"test\": \"test\"}", ContentType.APPLICATION_JSON)));
     }
 
     private void locationTestCase(Response response) throws IOException {
diff --git a/docs/reference/api-conventions.asciidoc b/docs/reference/api-conventions.asciidoc
index 712a7969a0..7e8ed1c1c8 100644
--- a/docs/reference/api-conventions.asciidoc
+++ b/docs/reference/api-conventions.asciidoc
@@ -670,7 +670,27 @@ The response looks like:
 
 For libraries that don't accept a request body for non-POST requests,
 you can pass the request body as the `source` query string parameter
-instead.
+instead. When using this method, the `source_content_type` parameter
+should also be passed with a media type value that indicates the format
+of the source, such as `application/json`.
+
+[float]
+=== Content-Type auto-detection
+
+deprecated[5.3.0, Provide the proper Content-Type header]
+
+The content sent in a request body or using the `source` query string
+parameter is inspected to automatically determine the content type
+(JSON, YAML, SMILE, or CBOR).
+
+A strict mode can be enabled which disables auto-detection and requires
+that all requests with a body have a Content-Type header that maps to
+a supported format. To enabled this strict mode, add the following
+setting to the `elasticsearch.yml` file:
+
+    http.content_type.required: true
+
+The default value is `false`.
 
 [[url-access-control]]
 == URL-based access control
@@ -682,7 +702,7 @@ the choice of specifying an index in the URL and on each individual request
 within the request body. This can make URL-based access control challenging.
 
 To prevent the user from overriding the index which has been specified in the
-URL, add this setting to the `config.yml` file:
+URL, add this setting to the `elasticsearch.yml` file:
 
     rest.action.multi.allow_explicit_index: false
 
diff --git a/docs/reference/migration/migrate_6_0/rest.asciidoc b/docs/reference/migration/migrate_6_0/rest.asciidoc
index 1999ff6517..f7b52b914d 100644
--- a/docs/reference/migration/migrate_6_0/rest.asciidoc
+++ b/docs/reference/migration/migrate_6_0/rest.asciidoc
@@ -13,6 +13,12 @@ has been removed in Elasticsearch 6.0.0.
 In previous versions of Elasticsearch, documents were allowed to contain duplicate keys. Elasticsearch 6.0.0
  enforces that all keys are unique. This applies to all content types: JSON, CBOR, Yaml and Smile.
 
+==== Content-Type Auto-detection
+
+In previous versions of Elasticsearch, having a proper Content-Type for the data in a request was not enforced.
+Elasticsearch 6.0.0 enforces that all requests with a body must have a supported Content-Type and this type will
+be used when parsing the data.
+
 ==== Boolean API parameters
 
 All REST APIs parameters (both request parameters and JSON body) support providing boolean "false" as the
diff --git a/docs/reference/modules/http.asciidoc b/docs/reference/modules/http.asciidoc
index 065c91349c..3682234f5e 100644
--- a/docs/reference/modules/http.asciidoc
+++ b/docs/reference/modules/http.asciidoc
@@ -100,6 +100,9 @@ simple message will be returned. Defaults to `true`
 
 |`http.pipelining.max_events` |The maximum number of events to be queued up in memory before a HTTP connection is closed, defaults to `10000`.
 
+|`http.content_type.required`|Enables or disables strict checking and usage of
+the `Content-Type` header for all requests with content, defaults to `false`.
+
 |=======================================================================
 
 It also uses the common
diff --git a/modules/lang-expression/src/test/java/org/elasticsearch/script/expression/StoredExpressionTests.java b/modules/lang-expression/src/test/java/org/elasticsearch/script/expression/StoredExpressionTests.java
index e2e7b81933..697dbf6257 100644
--- a/modules/lang-expression/src/test/java/org/elasticsearch/script/expression/StoredExpressionTests.java
+++ b/modules/lang-expression/src/test/java/org/elasticsearch/script/expression/StoredExpressionTests.java
@@ -21,6 +21,7 @@ package org.elasticsearch.script.expression;
 
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.Script;
 import org.elasticsearch.script.ScriptType;
@@ -53,9 +54,9 @@ public class StoredExpressionTests extends ESIntegTestCase {
         client().admin().cluster().preparePutStoredScript()
                 .setLang(ExpressionScriptEngineService.NAME)
                 .setId("script1")
-                .setContent(new BytesArray("{\"script\":\"2\"}"))
+                .setContent(new BytesArray("{\"script\":\"2\"}"), XContentType.JSON)
                 .get();
-        client().prepareIndex("test", "scriptTest", "1").setSource("{\"theField\":\"foo\"}").get();
+        client().prepareIndex("test", "scriptTest", "1").setSource("{\"theField\":\"foo\"}", XContentType.JSON).get();
         try {
             client().prepareUpdate("test", "scriptTest", "1")
                     .setScript(new Script(ScriptType.STORED, ExpressionScriptEngineService.NAME, "script1", Collections.emptyMap())).get();
diff --git a/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestPutSearchTemplateAction.java b/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestPutSearchTemplateAction.java
index 6c22b0160b..83925f0ec0 100644
--- a/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestPutSearchTemplateAction.java
+++ b/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestPutSearchTemplateAction.java
@@ -47,7 +47,7 @@ public class RestPutSearchTemplateAction extends BaseRestHandler {
         String id = request.param("id");
         BytesReference content = request.content();
 
-        PutStoredScriptRequest put = new PutStoredScriptRequest(id, Script.DEFAULT_TEMPLATE_LANG, content);
+        PutStoredScriptRequest put = new PutStoredScriptRequest(id, Script.DEFAULT_TEMPLATE_LANG, content, request.getXContentType());
         return channel -> client.admin().cluster().putStoredScript(put, new AcknowledgedRestListener<>(channel));
     }
 }
diff --git a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MultiSearchTemplateRequestTests.java b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MultiSearchTemplateRequestTests.java
index 3e4471509e..7dad299a40 100644
--- a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MultiSearchTemplateRequestTests.java
+++ b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MultiSearchTemplateRequestTests.java
@@ -20,6 +20,7 @@
 package org.elasticsearch.script.mustache;
 
 import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.script.ScriptType;
 import org.elasticsearch.test.ESTestCase;
@@ -34,7 +35,8 @@ public class MultiSearchTemplateRequestTests extends ESTestCase {
 
     public void testParseRequest() throws Exception {
         byte[] data = StreamsUtils.copyToBytesFromClasspath("/org/elasticsearch/script/mustache/simple-msearch-template.json");
-        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry()).withContent(new BytesArray(data)).build();
+        RestRequest restRequest = new FakeRestRequest.Builder(xContentRegistry())
+            .withContent(new BytesArray(data), XContentType.JSON).build();
 
         MultiSearchTemplateRequest request = RestMultiSearchTemplateAction.parseRequest(restRequest, true);
 
diff --git a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MustacheTests.java b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MustacheTests.java
index ba19febfd2..2b11df1939 100644
--- a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MustacheTests.java
+++ b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MustacheTests.java
@@ -279,7 +279,8 @@ public class MustacheTests extends ESTestCase {
                         .endArray()
                     .endObject();
 
-        Map<String, Object> ctx = Collections.singletonMap("ctx", XContentHelper.convertToMap(builder.bytes(), false).v2());
+        Map<String, Object> ctx =
+            Collections.singletonMap("ctx", XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2());
 
         assertScript("{{#ctx.bulks}}{{#toJson}}.{{/toJson}}{{/ctx.bulks}}", ctx,
                 equalTo("{\"index\":\"index-1\",\"id\":1,\"type\":\"type-1\"}{\"index\":\"index-2\",\"id\":2,\"type\":\"type-2\"}"));
@@ -320,7 +321,8 @@ public class MustacheTests extends ESTestCase {
                                                     .endArray()
                                                 .endObject();
 
-        Map<String, Object> ctx = Collections.singletonMap("ctx", XContentHelper.convertToMap(builder.bytes(), false).v2());
+        Map<String, Object> ctx =
+            Collections.singletonMap("ctx", XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2());
 
         assertScript("{{#join}}ctx.people.0.emails{{/join}}", ctx,
                 equalTo("john@smith.com,john.smith@email.com,jsmith@email.com"));
diff --git a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/SearchTemplateIT.java b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/SearchTemplateIT.java
index 8f6e77fc51..19a7023833 100644
--- a/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/SearchTemplateIT.java
+++ b/modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/SearchTemplateIT.java
@@ -24,6 +24,7 @@ import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.ScriptType;
@@ -159,7 +160,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                         "                    \"theField\" : \"{{fieldParam}}\"}" +
                         "       }" +
                         "}" +
-                        "}")));
+                        "}"), XContentType.JSON));
 
 
         assertAcked(client().admin().cluster().preparePutStoredScript()
@@ -171,18 +172,18 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                         "                    \"theField\" : \"{{fieldParam}}\"}" +
                         "       }" +
                         "}" +
-                        "}")));
+                        "}"), XContentType.JSON));
 
         GetStoredScriptResponse getResponse = client().admin().cluster()
                 .prepareGetStoredScript(MustacheScriptEngineService.NAME, "testTemplate").get();
         assertNotNull(getResponse.getSource());
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}"));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
@@ -221,7 +222,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                         "       }" +
                         "}" +
                         "}"
-                ))
+                ), XContentType.JSON)
         );
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(MustacheScriptEngineService.NAME)
@@ -233,7 +234,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                         "                    \"theField\" : \"{{fieldParam}}\"}" +
                         "       }" +
                         "}" +
-                        "}"))
+                        "}"), XContentType.JSON)
         );
         assertAcked(client().admin().cluster().preparePutStoredScript()
                 .setLang(MustacheScriptEngineService.NAME)
@@ -243,15 +244,15 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                         "             \"match\":{" +
                         "                    \"theField\" : \"{{fieldParam}}\"}" +
                         "       }" +
-                        "}"))
+                        "}"), XContentType.JSON)
         );
 
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}"));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
@@ -315,7 +316,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                     .setLang(MustacheScriptEngineService.NAME)
                     .setId("git01")
                     .setContent(new BytesArray("{\"template\":{\"query\": {\"match\": {\"searchtext\": {\"query\": \"{{P_Keyword1}}\"," +
-                            "\"type\": \"ooophrase_prefix\"}}}}}")));
+                            "\"type\": \"ooophrase_prefix\"}}}}}"), XContentType.JSON));
 
             GetStoredScriptResponse getResponse = client().admin().cluster()
                     .prepareGetStoredScript(MustacheScriptEngineService.NAME, "git01").get();
@@ -335,7 +336,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                     .setLang(MustacheScriptEngineService.NAME)
                     .setId("git01")
                     .setContent(new BytesArray("{\"query\": {\"match\": {\"searchtext\": {\"query\": \"{{P_Keyword1}}\"," +
-                            "\"type\": \"phrase_prefix\"}}}}")));
+                            "\"type\": \"phrase_prefix\"}}}}"), XContentType.JSON));
 
             SearchTemplateResponse searchResponse = new SearchTemplateRequestBuilder(client())
                     .setRequest(new SearchRequest("testindex").types("test"))
@@ -343,7 +344,6 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                     .get();
             assertHitCount(searchResponse.getResponse(), 1);
             assertWarnings("Deprecated field [type] used, replaced by [match_phrase and match_phrase_prefix query]");
-
         }
     }
 
@@ -353,14 +353,14 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                 client().admin().cluster().preparePutStoredScript()
                         .setLang(MustacheScriptEngineService.NAME)
                         .setId("4")
-                        .setContent(jsonBuilder().startObject().field("template", multiQuery).endObject().bytes())
+                        .setContent(jsonBuilder().startObject().field("template", multiQuery).endObject().bytes(), XContentType.JSON)
         );
         BulkRequestBuilder bulkRequestBuilder = client().prepareBulk();
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}"));
-        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}"));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "1").setSource("{\"theField\":\"foo\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "2").setSource("{\"theField\":\"foo 2\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "3").setSource("{\"theField\":\"foo 3\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "4").setSource("{\"theField\":\"foo 4\"}", XContentType.JSON));
+        bulkRequestBuilder.add(client().prepareIndex("test", "type", "5").setSource("{\"theField\":\"bar\"}", XContentType.JSON));
         bulkRequestBuilder.get();
         client().admin().indices().prepareRefresh().get();
 
diff --git a/modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java b/modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java
index 632c502283..97a65a29ad 100644
--- a/modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java
+++ b/modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java
@@ -57,6 +57,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.analysis.FieldNameAnalyzer;
 import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.DocumentMapperForType;
@@ -94,6 +95,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
     private final String field;
     private final String documentType;
     private final BytesReference document;
+    private final XContentType documentXContentType;
 
     private final String indexedDocumentIndex;
     private final String indexedDocumentType;
@@ -102,7 +104,16 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
     private final String indexedDocumentPreference;
     private final Long indexedDocumentVersion;
 
+    /**
+     * @deprecated use {@link #PercolateQueryBuilder(String, String, BytesReference, XContentType)} with the document content type to avoid
+     * autodetection
+     */
+    @Deprecated
     public PercolateQueryBuilder(String field, String documentType, BytesReference document) {
+        this(field, documentType, document, XContentFactory.xContentType(document));
+    }
+
+    public PercolateQueryBuilder(String field, String documentType, BytesReference document, XContentType documentXContentType) {
         if (field == null) {
             throw new IllegalArgumentException("[field] is a required argument");
         }
@@ -115,6 +126,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
         this.field = field;
         this.documentType = documentType;
         this.document = document;
+        this.documentXContentType = Objects.requireNonNull(documentXContentType);
         indexedDocumentIndex = null;
         indexedDocumentType = null;
         indexedDocumentId = null;
@@ -150,6 +162,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
         this.indexedDocumentPreference = indexedDocumentPreference;
         this.indexedDocumentVersion = indexedDocumentVersion;
         this.document = null;
+        this.documentXContentType = null;
     }
 
     /**
@@ -170,6 +183,15 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
             indexedDocumentVersion = null;
         }
         document = in.readOptionalBytesReference();
+        if (document != null) {
+            if (in.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+                documentXContentType = XContentType.readFrom(in);
+            } else {
+                documentXContentType = XContentFactory.xContentType(document);
+            }
+        } else {
+            documentXContentType = null;
+        }
     }
 
     @Override
@@ -188,6 +210,9 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
             out.writeBoolean(false);
         }
         out.writeOptionalBytesReference(document);
+        if (document != null && out.getVersion().after(Version.V_5_3_0_UNRELEASED)) { // TODO update to onOrAfter after backporting
+            documentXContentType.writeTo(out);
+        }
     }
 
     @Override
@@ -294,7 +319,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
 
         PercolateQueryBuilder queryBuilder;
         if (source != null) {
-            queryBuilder = new PercolateQueryBuilder(field, documentType, source);
+            queryBuilder = new PercolateQueryBuilder(field, documentType, source, XContentType.JSON);
         } else if (indexedDocumentId != null) {
             queryBuilder = new PercolateQueryBuilder(field, documentType, indexedDocumentIndex, indexedDocumentType,
                     indexedDocumentId, indexedDocumentRouting, indexedDocumentPreference, indexedDocumentVersion);
@@ -350,7 +375,8 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
                 "indexed document [" + indexedDocumentIndex + "/" + indexedDocumentType + "/" + indexedDocumentId + "] source disabled"
             );
         }
-        return new PercolateQueryBuilder(field, documentType, getResponse.getSourceAsBytesRef());
+        final BytesReference source = getResponse.getSourceAsBytesRef();
+        return new PercolateQueryBuilder(field, documentType, source, XContentFactory.xContentType(source));
     }
 
     @Override
@@ -370,7 +396,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
         DocumentMapperForType docMapperForType = mapperService.documentMapperWithAutoCreate(documentType);
         DocumentMapper docMapper = docMapperForType.getDocumentMapper();
 
-        ParsedDocument doc = docMapper.parse(source(context.index().getName(), documentType, "_temp_id", document));
+        ParsedDocument doc = docMapper.parse(source(context.index().getName(), documentType, "_temp_id", document, documentXContentType));
 
         FieldNameAnalyzer fieldNameAnalyzer = (FieldNameAnalyzer) docMapper.mappers().indexAnalyzer();
         // Need to this custom impl because FieldNameAnalyzer is strict and the percolator sometimes isn't when
@@ -435,6 +461,11 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
         return document;
     }
 
+    //pkg-private for testing
+    XContentType getXContentType() {
+        return documentXContentType;
+    }
+
     static IndexSearcher createMultiDocumentSearcher(Analyzer analyzer, ParsedDocument doc) {
         RAMDirectory ramDirectory = new RAMDirectory();
         try (IndexWriter indexWriter = new IndexWriter(ramDirectory, new IndexWriterConfig(analyzer))) {
diff --git a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolateQueryBuilderTests.java b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolateQueryBuilderTests.java
index e1589cba14..23f3fc77c2 100644
--- a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolateQueryBuilderTests.java
+++ b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolateQueryBuilderTests.java
@@ -27,14 +27,18 @@ import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.elasticsearch.ResourceNotFoundException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
 import org.elasticsearch.action.get.GetRequest;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.get.GetResult;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.ParseContext;
@@ -48,6 +52,7 @@ import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Base64;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -107,7 +112,7 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
             return new PercolateQueryBuilder(queryField, docType, indexedDocumentIndex, indexedDocumentType, indexedDocumentId,
                     indexedDocumentRouting, indexedDocumentPreference, indexedDocumentVersion);
         } else {
-            return new PercolateQueryBuilder(queryField, docType, documentSource);
+            return new PercolateQueryBuilder(queryField, docType, documentSource, XContentType.JSON);
         }
     }
 
@@ -155,7 +160,8 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
         IllegalStateException e = expectThrows(IllegalStateException.class, () -> pqb.toQuery(createShardContext()));
         assertThat(e.getMessage(), equalTo("query builder must be rewritten first"));
         QueryBuilder rewrite = pqb.rewrite(createShardContext());
-        PercolateQueryBuilder geoShapeQueryBuilder = new PercolateQueryBuilder(pqb.getField(), pqb.getDocumentType(), documentSource);
+        PercolateQueryBuilder geoShapeQueryBuilder =
+            new PercolateQueryBuilder(pqb.getField(), pqb.getDocumentType(), documentSource, XContentType.JSON);
         assertEquals(geoShapeQueryBuilder, rewrite);
     }
 
@@ -176,14 +182,16 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
 
     public void testRequiredParameters() {
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> {
-            new PercolateQueryBuilder(null, null, new BytesArray("{}"));
+            new PercolateQueryBuilder(null, null, new BytesArray("{}"), XContentType.JSON);
         });
         assertThat(e.getMessage(), equalTo("[field] is a required argument"));
 
-        e = expectThrows(IllegalArgumentException.class, () -> new PercolateQueryBuilder("_field", null, new BytesArray("{}")));
+        e = expectThrows(IllegalArgumentException.class,
+            () -> new PercolateQueryBuilder("_field", null, new BytesArray("{}"), XContentType.JSON));
         assertThat(e.getMessage(), equalTo("[document_type] is a required argument"));
 
-        e = expectThrows(IllegalArgumentException.class, () -> new PercolateQueryBuilder("_field", "_document_type", null));
+        e = expectThrows(IllegalArgumentException.class,
+            () -> new PercolateQueryBuilder("_field", "_document_type", null, null));
         assertThat(e.getMessage(), equalTo("[document] is a required argument"));
 
         e = expectThrows(IllegalArgumentException.class, () -> {
@@ -226,7 +234,7 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
         }
 
         Analyzer analyzer = new WhitespaceAnalyzer();
-        ParsedDocument parsedDocument = new ParsedDocument(null, null, "_id", "_type", null, docs, null, null);
+        ParsedDocument parsedDocument = new ParsedDocument(null, null, "_id", "_type", null, docs, null, null, null);
         IndexSearcher indexSearcher = PercolateQueryBuilder.createMultiDocumentSearcher(analyzer, parsedDocument);
         assertThat(indexSearcher.getIndexReader().numDocs(), equalTo(numDocs));
 
@@ -239,6 +247,26 @@ public class PercolateQueryBuilderTests extends AbstractQueryTestCase<PercolateQ
         assertThat(result.clauses().get(1).getOccur(), equalTo(BooleanClause.Occur.MUST_NOT));
     }
 
+    public void testSerializationBwc() throws IOException {
+        final byte[] data = Base64.getDecoder().decode("P4AAAAAFZmllbGQEdHlwZQAAAAAAAA57ImZvbyI6ImJhciJ9AAAAAA==");
+        final Version version = randomFrom(Version.V_5_0_0, Version.V_5_0_1, Version.V_5_0_2,
+            Version.V_5_0_3_UNRELEASED, Version.V_5_1_1_UNRELEASED, Version.V_5_1_2_UNRELEASED, Version.V_5_2_0_UNRELEASED);
+        try (StreamInput in = StreamInput.wrap(data)) {
+            in.setVersion(version);
+            PercolateQueryBuilder queryBuilder = new PercolateQueryBuilder(in);
+            assertEquals("type", queryBuilder.getDocumentType());
+            assertEquals("field", queryBuilder.getField());
+            assertEquals("{\"foo\":\"bar\"}", queryBuilder.getDocument().utf8ToString());
+            assertEquals(XContentType.JSON, queryBuilder.getXContentType());
+
+            try (BytesStreamOutput out = new BytesStreamOutput()) {
+                out.setVersion(version);
+                queryBuilder.writeTo(out);
+                assertArrayEquals(data, out.bytes().toBytesRef().bytes);
+            }
+        }
+    }
+
     private static BytesReference randomSource() {
         try {
             XContentBuilder xContent = XContentFactory.jsonBuilder();
diff --git a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorFieldMapperTests.java b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorFieldMapperTests.java
index 4d94ab3a29..d47e0a4614 100644
--- a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorFieldMapperTests.java
+++ b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorFieldMapperTests.java
@@ -565,7 +565,7 @@ public class PercolatorFieldMapperTests extends ESSingleNodeTestCase {
 
         ParsedDocument doc = mapperService.documentMapper(typeName).parse("test", typeName, "1",
                 XContentFactory.jsonBuilder().startObject()
-                        .rawField(fieldName, new BytesArray(query.string()))
+                        .rawField(fieldName, new BytesArray(query.string()), query.contentType())
                         .endObject().bytes());
         BytesRef querySource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
         Map<String, Object> parsedQuery = XContentHelper.convertToMap(new BytesArray(querySource), true).v2();
@@ -592,7 +592,7 @@ public class PercolatorFieldMapperTests extends ESSingleNodeTestCase {
 
         doc = mapperService.documentMapper(typeName).parse("test", typeName, "1",
                 XContentFactory.jsonBuilder().startObject()
-                        .rawField(fieldName, new BytesArray(query.string()))
+                        .rawField(fieldName, new BytesArray(query.string()), query.contentType())
                         .endObject().bytes());
         querySource = doc.rootDoc().getFields(fieldType.queryBuilderField.name())[0].binaryValue();
         parsedQuery = XContentHelper.convertToMap(new BytesArray(querySource), true).v2();
diff --git a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorQuerySearchIT.java b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorQuerySearchIT.java
index 1cce5fdbbd..07fc9aa2fe 100644
--- a/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorQuerySearchIT.java
+++ b/modules/percolator/src/test/java/org/elasticsearch/percolator/PercolatorQuerySearchIT.java
@@ -28,6 +28,7 @@ import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.index.query.MatchPhraseQueryBuilder;
 import org.elasticsearch.index.query.MultiMatchQueryBuilder;
@@ -94,7 +95,8 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
             .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
             .execute().actionGet();
         SearchResponse response = client().prepareSearch("index")
-            .setQuery(new PercolateQueryBuilder("query", "type", jsonBuilder().startObject().field("field1", "b").endObject().bytes()))
+            .setQuery(new PercolateQueryBuilder("query", "type", jsonBuilder().startObject().field("field1", "b").endObject().bytes(),
+                XContentType.JSON))
             .get();
         assertHitCount(response, 1);
         assertSearchHits(response, "1");
@@ -122,7 +124,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         BytesReference source = jsonBuilder().startObject().endObject().bytes();
         logger.info("percolating empty doc");
         SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
@@ -130,7 +132,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         source = jsonBuilder().startObject().field("field1", "value").endObject().bytes();
         logger.info("percolating doc with 1 field");
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .addSort("_uid", SortOrder.ASC)
                 .get();
         assertHitCount(response, 2);
@@ -140,7 +142,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         source = jsonBuilder().startObject().field("field1", "value").field("field2", "value").endObject().bytes();
         logger.info("percolating doc with 2 fields");
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .addSort("_uid", SortOrder.ASC)
                 .get();
         assertHitCount(response, 3);
@@ -199,7 +201,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         // Test long range:
         BytesReference source = jsonBuilder().startObject().field("field1", 12).endObject().bytes();
         SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("3"));
@@ -207,7 +209,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
 
         source = jsonBuilder().startObject().field("field1", 11).endObject().bytes();
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("1"));
@@ -215,7 +217,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         // Test double range:
         source = jsonBuilder().startObject().field("field2", 12).endObject().bytes();
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("6"));
@@ -223,7 +225,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
 
         source = jsonBuilder().startObject().field("field2", 11).endObject().bytes();
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("4"));
@@ -231,7 +233,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         // Test IP range:
         source = jsonBuilder().startObject().field("field3", "192.168.1.5").endObject().bytes();
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 2);
         assertThat(response.getHits().getAt(0).getId(), equalTo("9"));
@@ -239,7 +241,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
 
         source = jsonBuilder().startObject().field("field3", "192.168.1.4").endObject().bytes();
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("7"));
@@ -263,7 +265,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
                         .must(matchQuery("field2", "value"))
                 ).endObject()).get();
 
-        client().prepareIndex("test", "type", "1").setSource("{}").get();
+        client().prepareIndex("test", "type", "1").setSource("{}", XContentType.JSON).get();
         client().prepareIndex("test", "type", "2").setSource("field1", "value").get();
         client().prepareIndex("test", "type", "3").setSource("field1", "value", "field2", "value").get();
         client().admin().indices().prepareRefresh().get();
@@ -305,7 +307,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
             .setSource(jsonBuilder().startObject().field("query", matchAllQuery()).endObject())
             .get();
 
-        client().prepareIndex("test", "type", "1").setSource("{}").get();
+        client().prepareIndex("test", "type", "1").setSource("{}", XContentType.JSON).get();
         client().admin().indices().prepareRefresh().get();
 
         logger.info("percolating empty doc with source disabled");
@@ -376,7 +378,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
                 .field("field2", "the quick brown fox falls down into the well")
                 .endObject().bytes();
         SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", source))
+                .setQuery(new PercolateQueryBuilder("query", "type", source, XContentType.JSON))
                 .addSort("_uid", SortOrder.ASC)
                 .get();
         assertHitCount(response, 4);
@@ -423,7 +425,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
                 .field("field1", "The quick brown fox jumps over the lazy dog")
                 .endObject().bytes();
         SearchResponse searchResponse = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("query", "type", document))
+                .setQuery(new PercolateQueryBuilder("query", "type", document, XContentType.JSON))
                 .highlighter(new HighlightBuilder().field("field1"))
                 .addSort("_uid", SortOrder.ASC)
                 .get();
@@ -457,7 +459,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         client().admin().indices().prepareRefresh().get();
 
         SearchResponse response = client().prepareSearch().setQuery(
-                new PercolateQueryBuilder("query", "type", new BytesArray("{\"field\" : [\"brown\", \"fox\"]}"))
+                new PercolateQueryBuilder("query", "type", new BytesArray("{\"field\" : [\"brown\", \"fox\"]}"), XContentType.JSON)
         ).get();
         assertHitCount(response, 1);
         assertThat(response.getHits().getAt(0).getId(), equalTo("2"));
@@ -517,7 +519,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
 
         BytesReference source = jsonBuilder().startObject().field("field", "value").endObject().bytes();
         SearchResponse response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder(queryFieldName, "doc_type", source))
+                .setQuery(new PercolateQueryBuilder(queryFieldName, "doc_type", source, XContentType.JSON))
                 .setIndices("test1")
                 .get();
         assertHitCount(response, 1);
@@ -526,7 +528,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         assertThat(response.getHits().getAt(0).index(), equalTo("test1"));
 
         response = client().prepareSearch()
-                .setQuery(new PercolateQueryBuilder("object_field." + queryFieldName, "doc_type", source))
+                .setQuery(new PercolateQueryBuilder("object_field." + queryFieldName, "doc_type", source, XContentType.JSON))
                 .setIndices("test2")
                 .get();
         assertHitCount(response, 1);
@@ -576,7 +578,7 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
                                     .startObject().field("name", "virginia potts").endObject()
                                     .startObject().field("name", "tony stark").endObject()
                                 .endArray()
-                            .endObject().bytes()))
+                            .endObject().bytes(), XContentType.JSON))
                 .addSort("_doc", SortOrder.ASC)
                 .get();
         assertHitCount(response, 1);
@@ -590,14 +592,15 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
                                     .startObject().field("name", "virginia stark").endObject()
                                     .startObject().field("name", "tony stark").endObject()
                                 .endArray()
-                            .endObject().bytes()))
+                            .endObject().bytes(), XContentType.JSON))
                 .addSort("_doc", SortOrder.ASC)
                 .get();
         assertHitCount(response, 0);
 
         response = client().prepareSearch()
                 .setQuery(new PercolateQueryBuilder("query", "employee",
-                        XContentFactory.jsonBuilder().startObject().field("companyname", "notstark").endObject().bytes()))
+                        XContentFactory.jsonBuilder().startObject().field("companyname", "notstark").endObject().bytes(),
+                    XContentType.JSON))
                 .addSort("_doc", SortOrder.ASC)
                 .get();
         assertHitCount(response, 0);
@@ -632,16 +635,16 @@ public class PercolatorQuerySearchIT extends ESSingleNodeTestCase {
         MultiSearchResponse response = client().prepareMultiSearch()
             .add(client().prepareSearch("test")
                 .setQuery(new PercolateQueryBuilder("query", "type",
-                    jsonBuilder().startObject().field("field1", "b").endObject().bytes())))
+                    jsonBuilder().startObject().field("field1", "b").endObject().bytes(), XContentType.JSON)))
             .add(client().prepareSearch("test")
                 .setQuery(new PercolateQueryBuilder("query", "type",
-                    yamlBuilder().startObject().field("field1", "c").endObject().bytes())))
+                    yamlBuilder().startObject().field("field1", "c").endObject().bytes(), XContentType.JSON)))
             .add(client().prepareSearch("test")
                 .setQuery(new PercolateQueryBuilder("query", "type",
-                    smileBuilder().startObject().field("field1", "b c").endObject().bytes())))
+                    smileBuilder().startObject().field("field1", "b c").endObject().bytes(), XContentType.JSON)))
             .add(client().prepareSearch("test")
                 .setQuery(new PercolateQueryBuilder("query", "type",
-                    jsonBuilder().startObject().field("field1", "d").endObject().bytes())))
+                    jsonBuilder().startObject().field("field1", "d").endObject().bytes(), XContentType.JSON)))
             .add(client().prepareSearch("test")
                 .setQuery(new PercolateQueryBuilder("query", "type", "test", "type", "1", null, null, null)))
             .add(client().prepareSearch("test") // non existing doc, so error element
diff --git a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/TransportReindexAction.java b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/TransportReindexAction.java
index 03e4960cc9..aa0dcd1961 100644
--- a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/TransportReindexAction.java
+++ b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/TransportReindexAction.java
@@ -62,6 +62,10 @@ import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.mapper.VersionFieldMapper;
 import org.elasticsearch.index.reindex.remote.RemoteInfo;
@@ -72,6 +76,8 @@ import org.elasticsearch.tasks.Task;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
+import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -321,7 +327,24 @@ public class TransportReindexAction extends HandledTransportAction<ReindexReques
 
             // id and source always come from the found doc. Scripts can change them but they operate on the index request.
             index.id(doc.getId());
-            index.source(doc.getSource());
+
+            // the source xcontent type and destination could be different
+            final XContentType sourceXContentType = doc.getXContentType();
+            final XContentType mainRequestXContentType = mainRequest.getDestination().getContentType();
+            if (mainRequestXContentType != null && doc.getXContentType() != mainRequestXContentType) {
+                // we need to convert
+                try (XContentParser parser = sourceXContentType.xContent().createParser(NamedXContentRegistry.EMPTY, doc.getSource());
+                     XContentBuilder builder = XContentBuilder.builder(mainRequestXContentType.xContent())) {
+                    parser.nextToken();
+                    builder.copyCurrentStructure(parser);
+                    index.source(builder.bytes(), builder.contentType());
+                } catch (IOException e) {
+                    throw new UncheckedIOException("failed to convert hit from " + sourceXContentType + " to "
+                        + mainRequestXContentType, e);
+                }
+            } else {
+                index.source(doc.getSource(), doc.getXContentType());
+            }
 
             /*
              * The rest of the index request just has to be copied from the template. It may be changed later from scripts or the superclass
@@ -329,7 +352,6 @@ public class TransportReindexAction extends HandledTransportAction<ReindexReques
              */
             index.routing(mainRequest.getDestination().routing());
             index.parent(mainRequest.getDestination().parent());
-            index.contentType(mainRequest.getDestination().getContentType());
             index.setPipeline(mainRequest.getDestination().getPipeline());
             // OpType is synthesized from version so it is handled when we copy version above.
 
diff --git a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuilders.java b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuilders.java
index 8e61c14c6c..a6afa6df39 100644
--- a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuilders.java
+++ b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuilders.java
@@ -172,6 +172,22 @@ final class RemoteRequestBuilders {
     }
 
     static HttpEntity scrollEntity(String scroll) {
-        return new StringEntity(scroll, ContentType.TEXT_PLAIN);
+        try (XContentBuilder entity = JsonXContent.contentBuilder()) {
+            return new StringEntity(entity.startObject()
+                .field("scroll_id", scroll)
+                .endObject().string(), ContentType.APPLICATION_JSON);
+        } catch (IOException e) {
+            throw new ElasticsearchException("failed to build scroll entity", e);
+        }
+    }
+
+    static HttpEntity clearScrollEntity(String scroll) {
+        try (XContentBuilder entity = JsonXContent.contentBuilder()) {
+            return new StringEntity(entity.startObject()
+                .array("scroll_id", scroll)
+                .endObject().string(), ContentType.APPLICATION_JSON);
+        } catch (IOException e) {
+            throw new ElasticsearchException("failed to build clear scroll entity", e);
+        }
     }
 }
diff --git a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteResponseParsers.java b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteResponseParsers.java
index 31bcb3a825..e9807bdfa5 100644
--- a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteResponseParsers.java
+++ b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteResponseParsers.java
@@ -26,6 +26,7 @@ import org.elasticsearch.action.bulk.byscroll.ScrollableHitSource.Response;
 import org.elasticsearch.action.bulk.byscroll.ScrollableHitSource.SearchFailure;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.ParsingException;
+import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser;
@@ -33,7 +34,7 @@ import org.elasticsearch.common.xcontent.ObjectParser.ValueType;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentLocation;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.common.xcontent.json.JsonXContent;
+import org.elasticsearch.common.xcontent.XContentType;
 
 import java.io.IOException;
 import java.util.List;
@@ -54,7 +55,7 @@ final class RemoteResponseParsers {
     /**
      * Parser for an individual {@code hit} element.
      */
-    public static final ConstructingObjectParser<BasicHit, Void> HIT_PARSER =
+    public static final ConstructingObjectParser<BasicHit, XContentType> HIT_PARSER =
             new ConstructingObjectParser<>("hit", true, a -> {
                 int i = 0;
                 String index = (String) a[i++];
@@ -68,15 +69,16 @@ final class RemoteResponseParsers {
         HIT_PARSER.declareString(constructorArg(), new ParseField("_type"));
         HIT_PARSER.declareString(constructorArg(), new ParseField("_id"));
         HIT_PARSER.declareLong(optionalConstructorArg(), new ParseField("_version"));
-        HIT_PARSER.declareObject(BasicHit::setSource, (p, s) -> {
+        HIT_PARSER.declareObject(((basicHit, tuple) -> basicHit.setSource(tuple.v1(), tuple.v2())), (p, s) -> {
             try {
                 /*
                  * We spool the data from the remote back into xcontent so we can get bytes to send. There ought to be a better way but for
                  * now this should do.
                  */
-                try (XContentBuilder b = JsonXContent.contentBuilder()) {
+                try (XContentBuilder b = XContentBuilder.builder(s.xContent())) {
                     b.copyCurrentStructure(p);
-                    return b.bytes();
+                    // a hack but this lets us get the right xcontent type to go with the source
+                    return new Tuple<>(b.bytes(), s);
                 }
             } catch (IOException e) {
                 throw new ParsingException(p.getTokenLocation(), "[hit] failed to parse [_source]", e);
@@ -92,7 +94,7 @@ final class RemoteResponseParsers {
             String routing;
             String parent;
         }
-        ObjectParser<Fields, Void> fieldsParser = new ObjectParser<>("fields", Fields::new);
+        ObjectParser<Fields, XContentType> fieldsParser = new ObjectParser<>("fields", Fields::new);
         HIT_PARSER.declareObject((hit, fields) -> {
             hit.setRouting(fields.routing);
             hit.setParent(fields.parent);
@@ -105,7 +107,7 @@ final class RemoteResponseParsers {
     /**
      * Parser for the {@code hits} element. Parsed to an array of {@code [total (Long), hits (List<Hit>)]}.
      */
-    public static final ConstructingObjectParser<Object[], Void> HITS_PARSER =
+    public static final ConstructingObjectParser<Object[], XContentType> HITS_PARSER =
             new ConstructingObjectParser<>("hits", true, a -> a);
     static {
         HITS_PARSER.declareLong(constructorArg(), new ParseField("total"));
@@ -115,7 +117,7 @@ final class RemoteResponseParsers {
     /**
      * Parser for {@code failed} shards in the {@code _shards} elements.
      */
-    public static final ConstructingObjectParser<SearchFailure, Void> SEARCH_FAILURE_PARSER =
+    public static final ConstructingObjectParser<SearchFailure, XContentType> SEARCH_FAILURE_PARSER =
             new ConstructingObjectParser<>("failure", true, a -> {
                 int i = 0;
                 String index = (String) a[i++];
@@ -148,7 +150,7 @@ final class RemoteResponseParsers {
      * Parser for the {@code _shards} element. Throws everything out except the errors array if there is one. If there isn't one then it
      * parses to an empty list.
      */
-    public static final ConstructingObjectParser<List<Throwable>, Void> SHARDS_PARSER =
+    public static final ConstructingObjectParser<List<Throwable>, XContentType> SHARDS_PARSER =
             new ConstructingObjectParser<>("_shards", true, a -> {
                 @SuppressWarnings("unchecked")
                 List<Throwable> failures = (List<Throwable>) a[0];
@@ -159,7 +161,7 @@ final class RemoteResponseParsers {
         SHARDS_PARSER.declareObjectArray(optionalConstructorArg(), SEARCH_FAILURE_PARSER, new ParseField("failures"));
     }
 
-    public static final ConstructingObjectParser<Response, Void> RESPONSE_PARSER =
+    public static final ConstructingObjectParser<Response, XContentType> RESPONSE_PARSER =
             new ConstructingObjectParser<>("search_response", true, a -> {
                 int i = 0;
                 Throwable catastrophicFailure = (Throwable) a[i++];
@@ -198,9 +200,9 @@ final class RemoteResponseParsers {
      * Collects stuff about Throwables and attempts to rebuild them.
      */
     public static class ThrowableBuilder {
-        public static final BiFunction<XContentParser, Void, Throwable> PARSER;
+        public static final BiFunction<XContentParser, XContentType, Throwable> PARSER;
         static {
-            ObjectParser<ThrowableBuilder, Void> parser = new ObjectParser<>("reason", true, ThrowableBuilder::new);
+            ObjectParser<ThrowableBuilder, XContentType> parser = new ObjectParser<>("reason", true, ThrowableBuilder::new);
             PARSER = parser.andThen(ThrowableBuilder::build);
             parser.declareString(ThrowableBuilder::setType, new ParseField("type"));
             parser.declareString(ThrowableBuilder::setReason, new ParseField("reason"));
@@ -219,7 +221,7 @@ final class RemoteResponseParsers {
 
         public Throwable build() {
             Throwable t = buildWithoutCause();
-            if (causedBy != null) { 
+            if (causedBy != null) {
                 t.initCause(causedBy);
             }
             return t;
@@ -264,10 +266,10 @@ final class RemoteResponseParsers {
     /**
      * Parses the main action to return just the {@linkplain Version} that it returns. We throw everything else out.
      */
-    public static final ConstructingObjectParser<Version, Void> MAIN_ACTION_PARSER = new ConstructingObjectParser<>(
+    public static final ConstructingObjectParser<Version, XContentType> MAIN_ACTION_PARSER = new ConstructingObjectParser<>(
             "/", true, a -> (Version) a[0]);
     static {
-        ConstructingObjectParser<Version, Void> versionParser = new ConstructingObjectParser<>(
+        ConstructingObjectParser<Version, XContentType> versionParser = new ConstructingObjectParser<>(
                 "version", true, a -> Version.fromString((String) a[0]));
         versionParser.declareString(constructorArg(), new ParseField("number"));
         MAIN_ACTION_PARSER.declareObject(constructorArg(), versionParser, new ParseField("version"));
diff --git a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteScrollableHitSource.java b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteScrollableHitSource.java
index 5b0785fc0c..9c78d14c69 100644
--- a/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteScrollableHitSource.java
+++ b/modules/reindex/src/main/java/org/elasticsearch/index/reindex/remote/RemoteScrollableHitSource.java
@@ -21,6 +21,7 @@ package org.elasticsearch.index.reindex.remote;
 
 import org.apache.http.ContentTooLongException;
 import org.apache.http.HttpEntity;
+import org.apache.http.entity.ContentType;
 import org.apache.http.util.EntityUtils;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -57,6 +58,7 @@ import java.util.function.Consumer;
 import static java.util.Collections.emptyMap;
 import static org.elasticsearch.common.unit.TimeValue.timeValueMillis;
 import static org.elasticsearch.common.unit.TimeValue.timeValueNanos;
+import static org.elasticsearch.index.reindex.remote.RemoteRequestBuilders.clearScrollEntity;
 import static org.elasticsearch.index.reindex.remote.RemoteRequestBuilders.initialSearchEntity;
 import static org.elasticsearch.index.reindex.remote.RemoteRequestBuilders.initialSearchParams;
 import static org.elasticsearch.index.reindex.remote.RemoteRequestBuilders.initialSearchPath;
@@ -110,7 +112,7 @@ public class RemoteScrollableHitSource extends ScrollableHitSource {
 
     @Override
     protected void clearScroll(String scrollId, Runnable onCompletion) {
-        client.performRequestAsync("DELETE", scrollPath(), emptyMap(), scrollEntity(scrollId), new ResponseListener() {
+        client.performRequestAsync("DELETE", scrollPath(), emptyMap(), clearScrollEntity(scrollId), new ResponseListener() {
             @Override
             public void onSuccess(org.elasticsearch.client.Response response) {
                 logger.debug("Successfully cleared [{}]", scrollId);
@@ -140,7 +142,7 @@ public class RemoteScrollableHitSource extends ScrollableHitSource {
     }
 
     private <T> void execute(String method, String uri, Map<String, String> params, HttpEntity entity,
-            BiFunction<XContentParser, Void, T> parser, Consumer<? super T> listener) {
+                             BiFunction<XContentParser, XContentType, T> parser, Consumer<? super T> listener) {
         // Preserve the thread context so headers survive after the call
         java.util.function.Supplier<ThreadContext.StoredContext> contextSupplier = threadPool.getThreadContext().newRestorableContext(true);
         class RetryHelper extends AbstractRunnable {
@@ -160,7 +162,8 @@ public class RemoteScrollableHitSource extends ScrollableHitSource {
                                 InputStream content = responseEntity.getContent();
                                 XContentType xContentType = null;
                                 if (responseEntity.getContentType() != null) {
-                                    xContentType = XContentType.fromMediaTypeOrFormat(responseEntity.getContentType().getValue());
+                                    final String mimeType = ContentType.parse(responseEntity.getContentType().getValue()).getMimeType();
+                                    xContentType = XContentType.fromMediaType(mimeType);
                                 }
                                 if (xContentType == null) {
                                     try {
@@ -175,7 +178,7 @@ public class RemoteScrollableHitSource extends ScrollableHitSource {
                                 // EMPTY is safe here because we don't call namedObject
                                 try (XContentParser xContentParser = xContentType.xContent().createParser(NamedXContentRegistry.EMPTY,
                                     content)) {
-                                    parsedResponse = parser.apply(xContentParser, null);
+                                    parsedResponse = parser.apply(xContentParser, xContentType);
                                 } catch (ParsingException e) {
                                 /* Because we're streaming the response we can't get a copy of it here. The best we can do is hint that it
                                  * is totally wrong and we're probably not talking to Elasticsearch. */
diff --git a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/CancelTests.java b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/CancelTests.java
index 5e5716d6b1..01c5977e82 100644
--- a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/CancelTests.java
+++ b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/CancelTests.java
@@ -28,6 +28,7 @@ import org.elasticsearch.action.bulk.byscroll.BulkByScrollTask;
 import org.elasticsearch.action.ingest.DeletePipelineRequest;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.engine.Engine.Operation.Origin;
@@ -204,7 +205,7 @@ public class CancelTests extends ReindexTestCase {
                 "      \"test\" : {}\n" +
                 "  } ]\n" +
                 "}");
-        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline).get());
+        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, XContentType.JSON).get());
 
         testCancel(UpdateByQueryAction.NAME, updateByQuery().setPipeline("set-processed").source(INDEX), (response, total, modified) -> {
             assertThat(response, matcher().updated(modified).reasonCancelled(equalTo("by user request")));
@@ -237,7 +238,7 @@ public class CancelTests extends ReindexTestCase {
                 "      \"test\" : {}\n" +
                 "  } ]\n" +
                 "}");
-        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline).get());
+        assertAcked(client().admin().cluster().preparePutPipeline("set-processed", pipeline, XContentType.JSON).get());
 
         testCancel(UpdateByQueryAction.NAME, updateByQuery().setPipeline("set-processed").source(INDEX).setSlices(5),
                 (response, total, modified) -> {
diff --git a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/RestReindexActionTests.java b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/RestReindexActionTests.java
index abef7fb590..b190aee361 100644
--- a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/RestReindexActionTests.java
+++ b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/RestReindexActionTests.java
@@ -143,7 +143,7 @@ public class RestReindexActionTests extends ESTestCase {
                 body.endObject();
             }
             body.endObject();
-            request.withContent(body.bytes());
+            request.withContent(body.bytes(), body.contentType());
         }
         request.withParams(singletonMap("pipeline", "doesn't matter"));
         Exception e = expectThrows(IllegalArgumentException.class, () -> action.buildRequest(request.build()));
diff --git a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuildersTests.java b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuildersTests.java
index a93b017caa..f9ab72506a 100644
--- a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuildersTests.java
+++ b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/remote/RemoteRequestBuildersTests.java
@@ -186,7 +186,8 @@ public class RemoteRequestBuildersTests extends ESTestCase {
     public void testScrollEntity() throws IOException {
         String scroll = randomAsciiOfLength(30);
         HttpEntity entity = scrollEntity(scroll);
-        assertEquals(ContentType.TEXT_PLAIN.toString(), entity.getContentType().getValue());
-        assertEquals(scroll, Streams.copyToString(new InputStreamReader(entity.getContent(), StandardCharsets.UTF_8)));
+        assertEquals(ContentType.APPLICATION_JSON.toString(), entity.getContentType().getValue());
+        assertThat(Streams.copyToString(new InputStreamReader(entity.getContent(), StandardCharsets.UTF_8)),
+            containsString("\"" + scroll + "\""));
     }
 }
diff --git a/modules/transport-netty4/src/main/java/org/elasticsearch/http/netty4/Netty4HttpRequest.java b/modules/transport-netty4/src/main/java/org/elasticsearch/http/netty4/Netty4HttpRequest.java
index 10a2da21ac..c3b37ef7be 100644
--- a/modules/transport-netty4/src/main/java/org/elasticsearch/http/netty4/Netty4HttpRequest.java
+++ b/modules/transport-netty4/src/main/java/org/elasticsearch/http/netty4/Netty4HttpRequest.java
@@ -21,6 +21,7 @@ package org.elasticsearch.http.netty4;
 
 import io.netty.channel.Channel;
 import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpMethod;
 
 import org.elasticsearch.common.bytes.BytesArray;
@@ -30,7 +31,12 @@ import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.transport.netty4.Netty4Utils;
 
 import java.net.SocketAddress;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 public class Netty4HttpRequest extends RestRequest {
 
@@ -39,7 +45,7 @@ public class Netty4HttpRequest extends RestRequest {
     private final BytesReference content;
 
     Netty4HttpRequest(NamedXContentRegistry xContentRegistry, FullHttpRequest request, Channel channel) {
-        super(xContentRegistry, request.uri());
+        super(xContentRegistry, request.uri(), new HttpHeadersMap(request.headers()));
         this.request = request;
         this.channel = channel;
         if (request.content().isReadable()) {
@@ -120,14 +126,96 @@ public class Netty4HttpRequest extends RestRequest {
         return channel;
     }
 
-    @Override
-    public String header(String name) {
-        return request.headers().get(name);
-    }
+    /**
+     * A wrapper of {@link HttpHeaders} that implements a map to prevent copying unnecessarily. This class does not support modifications
+     * and due to the underlying implementation, it performs case insensitive lookups of key to values.
+     *
+     * It is important to note that this implementation does have some downsides in that each invocation of the
+     * {@link #values()} and {@link #entrySet()} methods will perform a copy of the values in the HttpHeaders rather than returning a
+     * view of the underlying values.
+     */
+    private static class HttpHeadersMap implements Map<String, List<String>> {
 
-    @Override
-    public Iterable<Map.Entry<String, String>> headers() {
-        return request.headers().entries();
-    }
+        private final HttpHeaders httpHeaders;
+
+        private HttpHeadersMap(HttpHeaders httpHeaders) {
+            this.httpHeaders = httpHeaders;
+        }
+
+        @Override
+        public int size() {
+            return httpHeaders.size();
+        }
+
+        @Override
+        public boolean isEmpty() {
+            return httpHeaders.isEmpty();
+        }
+
+        @Override
+        public boolean containsKey(Object key) {
+            return key instanceof String && httpHeaders.contains((String) key);
+        }
+
+        @Override
+        public boolean containsValue(Object value) {
+            return value instanceof List && httpHeaders.names().stream().map(httpHeaders::getAll).anyMatch(value::equals);
+        }
 
+        @Override
+        public List<String> get(Object key) {
+            return key instanceof String ? httpHeaders.getAll((String) key) : null;
+        }
+
+        @Override
+        public List<String> put(String key, List<String> value) {
+            throw new UnsupportedOperationException("modifications are not supported");
+        }
+
+        @Override
+        public List<String> remove(Object key) {
+            throw new UnsupportedOperationException("modifications are not supported");
+        }
+
+        @Override
+        public void putAll(Map<? extends String, ? extends List<String>> m) {
+            throw new UnsupportedOperationException("modifications are not supported");
+        }
+
+        @Override
+        public void clear() {
+            throw new UnsupportedOperationException("modifications are not supported");
+        }
+
+        @Override
+        public Set<String> keySet() {
+            return httpHeaders.names();
+        }
+
+        @Override
+        public Collection<List<String>> values() {
+            return httpHeaders.names().stream().map(k -> Collections.unmodifiableList(httpHeaders.getAll(k))).collect(Collectors.toList());
+        }
+
+        @Override
+        public Set<Entry<String, List<String>>> entrySet() {
+            return httpHeaders.names().stream().map(k -> new Entry<String, List<String>>() {
+
+                @Override
+                public String getKey() {
+                    return k;
+                }
+
+                @Override
+                public List<String> getValue() {
+                    return httpHeaders.getAll(k);
+                }
+
+                @Override
+                public List<String> setValue(List<String> value) {
+                    throw new UnsupportedOperationException("modifications are not supported");
+                }
+            }).collect(Collectors.toSet());
+        }
+    }
 }
diff --git a/modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpClient.java b/modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpClient.java
index 959a4d7c9f..1050404563 100644
--- a/modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpClient.java
+++ b/modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpClient.java
@@ -122,6 +122,7 @@ class Netty4HttpClient implements Closeable {
             HttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, method, uriAndBody.v1(), content);
             request.headers().add(HttpHeaderNames.HOST, "localhost");
             request.headers().add(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());
+            request.headers().add(HttpHeaderNames.CONTENT_TYPE, "application/json");
             requests.add(request);
         }
         return sendRequests(remoteAddress, requests);
diff --git a/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingIT.java b/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingIT.java
index c4de761c8e..92cbb2e6e3 100644
--- a/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingIT.java
+++ b/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingIT.java
@@ -22,6 +22,7 @@ import org.elasticsearch.action.admin.indices.mapping.get.GetMappingsResponse;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.plugin.mapper.MapperSizePlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -107,7 +108,7 @@ public class SizeMappingIT extends ESIntegTestCase {
         assertAcked(prepareCreate("test").addMapping("type", "_size", "enabled=true"));
         final String source = "{\"f\":10}";
         indexRandom(true,
-                client().prepareIndex("test", "type", "1").setSource(source));
+                client().prepareIndex("test", "type", "1").setSource(source, XContentType.JSON));
         GetResponse getResponse = client().prepareGet("test", "type", "1").setStoredFields("_size").get();
         assertNotNull(getResponse.getField("_size"));
         assertEquals(source.length(), getResponse.getField("_size").getValue());
diff --git a/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingTests.java b/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingTests.java
index 3fa5300fb4..2cde1b1bd0 100644
--- a/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingTests.java
+++ b/plugins/mapper-size/src/test/java/org/elasticsearch/index/mapper/size/SizeMappingTests.java
@@ -27,6 +27,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
@@ -60,7 +61,7 @@ public class SizeMappingTests extends ESSingleNodeTestCase {
             .field("field", "value")
             .endObject()
             .bytes();
-        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source));
+        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source, XContentType.JSON));
 
         boolean stored = false;
         boolean points = false;
@@ -81,7 +82,7 @@ public class SizeMappingTests extends ESSingleNodeTestCase {
             .field("field", "value")
             .endObject()
             .bytes();
-        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source));
+        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source, XContentType.JSON));
 
         assertThat(doc.rootDoc().getField("_size"), nullValue());
     }
@@ -95,7 +96,7 @@ public class SizeMappingTests extends ESSingleNodeTestCase {
             .field("field", "value")
             .endObject()
             .bytes();
-        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source));
+        ParsedDocument doc = docMapper.parse(SourceToParse.source("test", "type", "1", source, XContentType.JSON));
 
         assertThat(doc.rootDoc().getField("_size"), nullValue());
     }
diff --git a/plugins/repository-azure/src/test/java/org/elasticsearch/cloud/azure/storage/AzureStorageSettingsFilterTests.java b/plugins/repository-azure/src/test/java/org/elasticsearch/cloud/azure/storage/AzureStorageSettingsFilterTests.java
index e82ed3a187..b67073d7d3 100644
--- a/plugins/repository-azure/src/test/java/org/elasticsearch/cloud/azure/storage/AzureStorageSettingsFilterTests.java
+++ b/plugins/repository-azure/src/test/java/org/elasticsearch/cloud/azure/storage/AzureStorageSettingsFilterTests.java
@@ -62,7 +62,7 @@ public class AzureStorageSettingsFilterTests extends ESTestCase {
         settings.toXContent(xContentBuilder, request);
         xContentBuilder.endObject();
         String filteredSettingsString = xContentBuilder.string();
-        filteredSettings = Settings.builder().loadFromSource(filteredSettingsString).build();
+        filteredSettings = Settings.builder().loadFromSource(filteredSettingsString, xContentBuilder.contentType()).build();
         assertThat(filteredSettings.getAsMap().keySet(), contains("cloud.azure.storage.azure1.default"));
     }
 
diff --git a/qa/backwards-5.0/src/test/java/org/elasticsearch/backwards/IndexingIT.java b/qa/backwards-5.0/src/test/java/org/elasticsearch/backwards/IndexingIT.java
index b5bd18aba5..90a5808710 100644
--- a/qa/backwards-5.0/src/test/java/org/elasticsearch/backwards/IndexingIT.java
+++ b/qa/backwards-5.0/src/test/java/org/elasticsearch/backwards/IndexingIT.java
@@ -19,6 +19,7 @@
 package org.elasticsearch.backwards;
 
 import org.apache.http.HttpHost;
+import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.util.EntityUtils;
 import org.elasticsearch.Version;
@@ -70,7 +71,7 @@ public class IndexingIT extends ESRestTestCase {
 
     private void createIndex(String name, Settings settings) throws IOException {
         assertOK(client().performRequest("PUT", name, Collections.emptyMap(),
-            new StringEntity("{ \"settings\": " + Strings.toString(settings) + " }")));
+            new StringEntity("{ \"settings\": " + Strings.toString(settings) + " }", ContentType.APPLICATION_JSON)));
     }
 
     private void updateIndexSetting(String name, Settings.Builder settings) throws IOException {
@@ -85,13 +86,14 @@ public class IndexingIT extends ESRestTestCase {
         for (int i = 0; i < numDocs; i++) {
             final int id = idStart + i;
             assertOK(client().performRequest("PUT", index + "/test/" + id, emptyMap(),
-                new StringEntity("{\"test\": \"test_" + id + "\"}")));
+                new StringEntity("{\"test\": \"test_" + id + "\"}", ContentType.APPLICATION_JSON)));
         }
         return numDocs;
     }
 
     public void testSeqNoCheckpoints() throws Exception {
         Nodes nodes = buildNodeAndVersions();
+        assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
         logger.info("cluster discovered: {}", nodes.toString());
         final String bwcNames = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.joining(","));
         Settings.Builder settings = Settings.builder()
diff --git a/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsDisabledIT.java b/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsDisabledIT.java
index 2cf681e9e5..51dbad22de 100644
--- a/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsDisabledIT.java
+++ b/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsDisabledIT.java
@@ -24,7 +24,6 @@ import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 import org.elasticsearch.common.network.NetworkModule;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
 import org.elasticsearch.test.ESIntegTestCase.Scope;
 
@@ -54,7 +53,7 @@ public class DetailedErrorsDisabledIT extends HttpSmokeTestCase {
             fail("request should have failed");
         } catch(ResponseException e) {
             Response response = e.getResponse();
-            assertThat(response.getHeader("Content-Type"), is("application/json"));
+            assertThat(response.getHeader("Content-Type"), is("application/json; charset=UTF-8"));
             assertThat(EntityUtils.toString(e.getResponse().getEntity()), is("{\"error\":\"error traces in responses are disabled.\"}"));
             assertThat(response.getStatusLine().getStatusCode(), is(400));
         }
diff --git a/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsEnabledIT.java b/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsEnabledIT.java
index cd3cf1a38d..d0b80595a2 100644
--- a/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsEnabledIT.java
+++ b/qa/smoke-test-http/src/test/java/org/elasticsearch/http/DetailedErrorsEnabledIT.java
@@ -22,7 +22,6 @@ package org.elasticsearch.http;
 import org.apache.http.util.EntityUtils;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
-import org.elasticsearch.test.ESIntegTestCase;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -52,7 +51,7 @@ public class DetailedErrorsEnabledIT extends HttpSmokeTestCase {
             fail("request should have failed");
         } catch(ResponseException e) {
             Response response = e.getResponse();
-            assertThat(response.getHeader("Content-Type"), containsString("application/json"));
+            assertThat(response.getHeader("Content-Type"), containsString("application/json; charset=UTF-8"));
             assertThat(EntityUtils.toString(response.getEntity()),
                     not(containsString("\"stack_trace\":\"[Validation Failed: 1: index / indices is missing;]; "
                     + "nested: ActionRequestValidationException[Validation Failed: 1:")));
diff --git a/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java b/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java
index 1e716d4f16..20c869d38c 100644
--- a/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java
@@ -41,6 +41,7 @@ import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.util.BigArrays;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.MapperTestUtils;
@@ -473,17 +474,23 @@ public abstract class IndexShardTestCase extends ESTestCase {
     }
 
     protected Engine.Index indexDoc(IndexShard shard, String type, String id, String source) throws IOException {
+        return indexDoc(shard, type, id, source, XContentType.JSON);
+    }
+
+    protected Engine.Index indexDoc(IndexShard shard, String type, String id, String source, XContentType xContentType) throws IOException {
         final Engine.Index index;
         if (shard.routingEntry().primary()) {
             index = shard.prepareIndexOnPrimary(
-                SourceToParse.source(SourceToParse.Origin.PRIMARY, shard.shardId().getIndexName(), type, id, new BytesArray(source)),
+                SourceToParse.source(SourceToParse.Origin.PRIMARY, shard.shardId().getIndexName(), type, id, new BytesArray(source),
+                    xContentType),
                 Versions.MATCH_ANY,
                 VersionType.INTERNAL,
                 IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP,
                 false);
         } else {
             index = shard.prepareIndexOnReplica(
-                SourceToParse.source(SourceToParse.Origin.PRIMARY, shard.shardId().getIndexName(), type, id, new BytesArray(source)),
+                SourceToParse.source(SourceToParse.Origin.PRIMARY, shard.shardId().getIndexName(), type, id, new BytesArray(source),
+                    xContentType),
                 randomInt(1 << 10), 1, VersionType.EXTERNAL, IndexRequest.UNSET_AUTO_GENERATED_TIMESTAMP, false);
         }
         shard.index(index);
diff --git a/test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java b/test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java
index 245ea6c08f..b1d66fd399 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java
@@ -96,6 +96,7 @@ import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.discovery.Discovery;
@@ -1226,10 +1227,10 @@ public abstract class ESIntegTestCase extends ESTestCase {
      *   return client().prepareIndex(index, type, id).setSource(source).execute().actionGet();
      * </pre>
      * <p>
-     * where source is a String.
+     * where source is a JSON String.
      */
     protected final IndexResponse index(String index, String type, String id, String source) {
-        return client().prepareIndex(index, type, id).setSource(source).execute().actionGet();
+        return client().prepareIndex(index, type, id).setSource(source, XContentType.JSON).execute().actionGet();
     }
 
     /**
@@ -1387,7 +1388,7 @@ public abstract class ESIntegTestCase extends ESTestCase {
                 String id = randomRealisticUnicodeOfLength(unicodeLen) + Integer.toString(dummmyDocIdGenerator.incrementAndGet());
                 String index = RandomPicks.randomFrom(random, indices);
                 bogusIds.add(new Tuple<>(index, id));
-                builders.add(client().prepareIndex(index, RANDOM_BOGUS_TYPE, id).setSource("{}"));
+                builders.add(client().prepareIndex(index, RANDOM_BOGUS_TYPE, id).setSource("{}", XContentType.JSON));
             }
         }
         final String[] indices = indicesSet.toArray(new String[indicesSet.size()]);
diff --git a/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java b/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
index c7203f9719..633a04f5f6 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
@@ -294,7 +294,7 @@ public abstract class ESTestCase extends LuceneTestCase {
     }
 
     private void ensureNoWarnings() throws IOException {
-        //Check that there are no unaccounted warning headers. These should be checked with {@link #checkWarningHeaders(String...)} in the
+        //Check that there are no unaccounted warning headers. These should be checked with {@link #assertWarnings(String...)} in the
         //appropriate test
         try {
             final List<String> warnings = threadContext.getResponseHeaders().get(DeprecationLogger.WARNING_HEADER);
diff --git a/test/framework/src/main/java/org/elasticsearch/test/XContentTestUtils.java b/test/framework/src/main/java/org/elasticsearch/test/XContentTestUtils.java
index 31380e25eb..dcad7187fb 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/XContentTestUtils.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/XContentTestUtils.java
@@ -41,7 +41,7 @@ public final class XContentTestUtils {
         builder.startObject();
         part.toXContent(builder, EMPTY_PARAMS);
         builder.endObject();
-        return XContentHelper.convertToMap(builder.bytes(), false).v2();
+        return XContentHelper.convertToMap(builder.bytes(), false, builder.contentType()).v2();
     }
 
 
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestChannel.java b/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestChannel.java
index 3d1ce29143..bca4af7bd6 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestChannel.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestChannel.java
@@ -19,9 +19,9 @@
 package org.elasticsearch.test.rest;
 
 import org.elasticsearch.common.Nullable;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.AbstractRestChannel;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
@@ -53,8 +53,8 @@ public final class FakeRestChannel extends AbstractRestChannel {
     }
 
     @Override
-    public XContentBuilder newBuilder(@Nullable BytesReference autoDetectSource, boolean useFiltering) throws IOException {
-        return super.newBuilder(autoDetectSource, useFiltering);
+    public XContentBuilder newBuilder(@Nullable XContentType requestContentType, boolean useFiltering) throws IOException {
+        return super.newBuilder(requestContentType, useFiltering);
     }
 
     @Override
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestRequest.java b/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestRequest.java
index ae8c4c82c4..83caf0293e 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestRequest.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/FakeRestRequest.java
@@ -21,28 +21,31 @@ package org.elasticsearch.test.rest;
 
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.rest.RestRequest;
 
+import java.net.SocketAddress;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 public class FakeRestRequest extends RestRequest {
 
-    private final Map<String, String> headers;
     private final BytesReference content;
     private final Method method;
-
+    private final SocketAddress remoteAddress;
 
     public FakeRestRequest() {
-        this(NamedXContentRegistry.EMPTY, new HashMap<>(), new HashMap<>(), null, Method.GET, "/");
+        this(NamedXContentRegistry.EMPTY, new HashMap<>(), new HashMap<>(), null, Method.GET, "/", null);
     }
 
-    private FakeRestRequest(NamedXContentRegistry xContentRegistry, Map<String, String> headers, Map<String, String> params,
-            BytesReference content, Method method, String path) {
-        super(xContentRegistry, params, path);
-        this.headers = headers;
+    private FakeRestRequest(NamedXContentRegistry xContentRegistry, Map<String, List<String>> headers, Map<String, String> params,
+                            BytesReference content, Method method, String path, SocketAddress remoteAddress) {
+        super(xContentRegistry, params, path, headers);
         this.content = content;
         this.method = method;
+        this.remoteAddress = remoteAddress;
     }
 
     @Override
@@ -66,19 +69,14 @@ public class FakeRestRequest extends RestRequest {
     }
 
     @Override
-    public String header(String name) {
-        return headers.get(name);
-    }
-
-    @Override
-    public Iterable<Map.Entry<String, String>> headers() {
-        return headers.entrySet();
+    public SocketAddress getRemoteAddress() {
+        return remoteAddress;
     }
 
     public static class Builder {
         private final NamedXContentRegistry xContentRegistry;
 
-        private Map<String, String> headers = new HashMap<>();
+        private Map<String, List<String>> headers = new HashMap<>();
 
         private Map<String, String> params = new HashMap<>();
 
@@ -88,11 +86,13 @@ public class FakeRestRequest extends RestRequest {
 
         private Method method = Method.GET;
 
+        private SocketAddress address = null;
+
         public Builder(NamedXContentRegistry xContentRegistry) {
             this.xContentRegistry = xContentRegistry;
         }
 
-        public Builder withHeaders(Map<String, String> headers) {
+        public Builder withHeaders(Map<String, List<String>> headers) {
             this.headers = headers;
             return this;
         }
@@ -102,8 +102,11 @@ public class FakeRestRequest extends RestRequest {
             return this;
         }
 
-        public Builder withContent(BytesReference content) {
+        public Builder withContent(BytesReference content, XContentType xContentType) {
             this.content = content;
+            if (xContentType != null) {
+                headers.put("Content-Type", Collections.singletonList(xContentType.mediaType()));
+            }
             return this;
         }
 
@@ -117,8 +120,13 @@ public class FakeRestRequest extends RestRequest {
             return this;
         }
 
+        public Builder withRemoteAddress(SocketAddress address) {
+            this.address = address;
+            return this;
+        }
+
         public FakeRestRequest build() {
-            return new FakeRestRequest(xContentRegistry, headers, params, content, method, path);
+            return new FakeRestRequest(xContentRegistry, headers, params, content, method, path, address);
         }
 
     }
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestClient.java b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestClient.java
index c18dad907b..aa51efaa33 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestClient.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestClient.java
@@ -55,13 +55,15 @@ public class ClientYamlTestClient {
     private final ClientYamlSuiteRestSpec restSpec;
     private final RestClient restClient;
     private final Version esVersion;
+    private final Map<HttpHost, Version> hostVersionMap;
 
     public ClientYamlTestClient(ClientYamlSuiteRestSpec restSpec, RestClient restClient, List<HttpHost> hosts,
-                                Version esVersion) throws IOException {
+                                Version esVersion, Map<HttpHost, Version> hostVersionMap) throws IOException {
         assert hosts.size() > 0;
         this.restSpec = restSpec;
         this.restClient = restClient;
         this.esVersion = esVersion;
+        this.hostVersionMap = hostVersionMap;
     }
 
     public Version getEsVersion() {
@@ -86,9 +88,9 @@ public class ClientYamlTestClient {
             // And everything else is a url parameter!
             try {
                 Response response = restClient.performRequest(method, path, queryStringParams, entity);
-                return new ClientYamlTestResponse(response);
+                return new ClientYamlTestResponse(response, hostVersionMap.get(response.getHost()));
             } catch(ResponseException e) {
-                throw new ClientYamlTestResponseException(e);
+                throw new ClientYamlTestResponseException(e, hostVersionMap.get(e.getResponse().getHost()));
             }
         }
 
@@ -122,6 +124,9 @@ public class ClientYamlTestClient {
             if (supportedMethods.contains("GET") && RandomizedTest.rarely()) {
                 logger.debug("sending the request body as source param with GET method");
                 queryStringParams.put("source", body);
+                if (esVersion.after(Version.V_5_3_0_UNRELEASED)) { // TODO make onOrAfter with backport
+                    queryStringParams.put("source_content_type", ContentType.APPLICATION_JSON.toString());
+                }
                 requestMethod = "GET";
             } else {
                 requestMethod = RandomizedTest.randomFrom(supportedMethods);
@@ -168,9 +173,9 @@ public class ClientYamlTestClient {
         logger.debug("calling api [{}]", apiName);
         try {
             Response response = restClient.performRequest(requestMethod, requestPath, queryStringParams, requestBody, requestHeaders);
-            return new ClientYamlTestResponse(response);
+            return new ClientYamlTestResponse(response, hostVersionMap.get(response.getHost()));
         } catch(ResponseException e) {
-            throw new ClientYamlTestResponseException(e);
+            throw new ClientYamlTestResponseException(e, hostVersionMap.get(e.getResponse().getHost()));
         }
     }
 
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestExecutionContext.java b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestExecutionContext.java
index 8215105887..27653a13f2 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestExecutionContext.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestExecutionContext.java
@@ -71,9 +71,9 @@ public class ClientYamlTestExecutionContext {
             throw e;
         } finally {
             // if we hit a bad exception the response is null
-            Object repsponseBody = response != null ? response.getBody() : null;
+            Object responseBody = response != null ? response.getBody() : null;
             //we always stash the last response body
-            stash.stashValue("body", repsponseBody);
+            stash.stashValue("body", responseBody);
         }
     }
 
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponse.java b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponse.java
index 481ae752d0..f47cfd68d4 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponse.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponse.java
@@ -21,6 +21,7 @@ package org.elasticsearch.test.rest.yaml;
 import org.apache.http.Header;
 import org.apache.http.client.methods.HttpHead;
 import org.apache.http.util.EntityUtils;
+import org.elasticsearch.Version;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.common.xcontent.XContentType;
 
@@ -37,10 +38,12 @@ public class ClientYamlTestResponse {
 
     private final Response response;
     private final String body;
+    private final Version nodeVersion;
     private ObjectPath parsedResponse;
 
-    ClientYamlTestResponse(Response response) throws IOException {
+    ClientYamlTestResponse(Response response, Version version) throws IOException {
         this.response = response;
+        this.nodeVersion = version;
         if (response.getEntity() != null) {
             try {
                 this.body = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
@@ -80,7 +83,18 @@ public class ClientYamlTestResponse {
         List<String> warningHeaders = new ArrayList<>();
         for (Header header : response.getHeaders()) {
             if (header.getName().equals("Warning")) {
-                warningHeaders.add(header.getValue());
+                if (nodeVersion.after(Version.V_5_3_0_UNRELEASED) && response.getRequestLine().getMethod().equals("GET")
+                    && response.getRequestLine().getUri().contains("source")
+                    && response.getRequestLine().getUri().contains("source_content_type") == false && header.getValue().startsWith(
+                        "Deprecated use of the [source] parameter without the [source_content_type] parameter.")) {
+                    // this is because we do not send the source content type header when the node is 5.3.0 or below and the request
+                    // might have been sent to a node with a version > 5.3.0 when running backwards 5.0 tests. The Java RestClient
+                    // has control of the node the request is sent to so we can only detect this after the fact right now
+                    // TODO remove this when we bump versions
+                } else {
+                    warningHeaders.add(header.getValue());
+                }
+
             }
         }
         return warningHeaders;
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponseException.java b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponseException.java
index 7d983d4802..48a7ee578d 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponseException.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ClientYamlTestResponseException.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.test.rest.yaml;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.client.ResponseException;
 
 import java.io.IOException;
@@ -32,10 +33,10 @@ public class ClientYamlTestResponseException extends IOException {
     private final ClientYamlTestResponse restTestResponse;
     private final ResponseException responseException;
 
-    ClientYamlTestResponseException(ResponseException responseException) throws IOException {
+    ClientYamlTestResponseException(ResponseException responseException, Version version) throws IOException {
         super(responseException);
         this.responseException = responseException;
-        this.restTestResponse = new ClientYamlTestResponse(responseException.getResponse());
+        this.restTestResponse = new ClientYamlTestResponse(responseException.getResponse(), version);
     }
 
     /**
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ESClientYamlSuiteTestCase.java b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ESClientYamlSuiteTestCase.java
index a45d92c969..411f657329 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ESClientYamlSuiteTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/yaml/ESClientYamlSuiteTestCase.java
@@ -53,6 +53,7 @@ import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -125,6 +126,7 @@ public abstract class ESClientYamlSuiteTestCase extends ESRestTestCase {
             validateSpec(restSpec);
             List<HttpHost> hosts = getClusterHosts();
             RestClient restClient = client();
+            Tuple<Version, Map<HttpHost, Version>> versionMapTuple = readVersionsFromInfo(restClient, hosts.size());
             Version esVersion;
             try {
                 Tuple<Version, Version> versionVersionTuple = readVersionsFromCatNodes(restClient);
@@ -135,13 +137,14 @@ public abstract class ESClientYamlSuiteTestCase extends ESRestTestCase {
             } catch (ResponseException ex) {
                 if (ex.getResponse().getStatusLine().getStatusCode() == 403) {
                     logger.warn("Fallback to simple info '/' request, _cat/nodes is not authorized");
-                    esVersion = readVersionsFromInfo(restClient, hosts.size());
+                    esVersion = versionMapTuple.v1();
                     logger.info("initializing yaml client, minimum es version: [{}] hosts: {}", esVersion, hosts);
                 } else {
                     throw ex;
                 }
             }
-            ClientYamlTestClient clientYamlTestClient = new ClientYamlTestClient(restSpec, restClient, hosts, esVersion);
+            ClientYamlTestClient clientYamlTestClient =
+                new ClientYamlTestClient(restSpec, restClient, hosts, esVersion, versionMapTuple.v2());
             restTestExecutionContext = new ClientYamlTestExecutionContext(clientYamlTestClient);
             adminExecutionContext = new ClientYamlTestExecutionContext(clientYamlTestClient);
             String[] blacklist = resolvePathsProperty(REST_TESTS_BLACKLIST, null);
@@ -290,7 +293,7 @@ public abstract class ESClientYamlSuiteTestCase extends ESRestTestCase {
     private static Tuple<Version, Version> readVersionsFromCatNodes(RestClient restClient) throws IOException {
         // we simply go to the _cat/nodes API and parse all versions in the cluster
         Response response = restClient.performRequest("GET", "/_cat/nodes", Collections.singletonMap("h", "version,master"));
-        ClientYamlTestResponse restTestResponse = new ClientYamlTestResponse(response);
+        ClientYamlTestResponse restTestResponse = new ClientYamlTestResponse(response, Version.CURRENT);
         String nodesCatResponse = restTestResponse.getBodyAsString();
         String[] split = nodesCatResponse.split("\n");
         Version version = null;
@@ -313,12 +316,13 @@ public abstract class ESClientYamlSuiteTestCase extends ESRestTestCase {
         return new Tuple<>(version, masterVersion);
     }
 
-    private static Version readVersionsFromInfo(RestClient restClient, int numHosts) throws IOException {
+    private static Tuple<Version, Map<HttpHost, Version>> readVersionsFromInfo(RestClient restClient, int numHosts) throws IOException {
         Version version = null;
+        Map<HttpHost, Version> hostVersionMap = new HashMap<>();
         for (int i = 0; i < numHosts; i++) {
             //we don't really use the urls here, we rely on the client doing round-robin to touch all the nodes in the cluster
             Response response = restClient.performRequest("GET", "/");
-            ClientYamlTestResponse restTestResponse = new ClientYamlTestResponse(response);
+            ClientYamlTestResponse restTestResponse = new ClientYamlTestResponse(response, Version.CURRENT);
             Object latestVersion = restTestResponse.evaluate("version.number");
             if (latestVersion == null) {
                 throw new RuntimeException("elasticsearch version not found in the response");
@@ -329,8 +333,9 @@ public abstract class ESClientYamlSuiteTestCase extends ESRestTestCase {
             } else if (version.onOrAfter(currentVersion)) {
                 version = currentVersion;
             }
+            hostVersionMap.put(response.getHost(), currentVersion);
         }
-        return version;
+        return new Tuple<>(version, Collections.unmodifiableMap(hostVersionMap));
     }
 
     public void test() throws IOException {
author	Jay Modi <jaymode@users.noreply.github.com>	2017-02-02 14:07:13 -0500
committer	GitHub <noreply@github.com>	2017-02-02 14:07:13 -0500
commit	7520a107bee67099338813728147d2aee25ed240 (patch)
tree	22828e74c5aa601c185c36c7463665fbfeaa4c51
parent	b41d5747f0bd67dad05c8168312ba456bcdaebda (diff)