diff --git a/client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java b/client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java
index 38dbbb8f151..d448275d358 100644
--- a/client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java
+++ b/client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java
@@ -486,9 +486,18 @@ final class RequestConverters {
     }
 
     static Request reindex(ReindexRequest reindexRequest) throws IOException {
+        return prepareReindexRequest(reindexRequest, true);
+    }
+
+    static Request submitReindex(ReindexRequest reindexRequest) throws IOException {
+        return prepareReindexRequest(reindexRequest, false);
+    }
+
+    private static Request prepareReindexRequest(ReindexRequest reindexRequest, boolean waitForCompletion) throws IOException {
         String endpoint = new EndpointBuilder().addPathPart("_reindex").build();
         Request request = new Request(HttpPost.METHOD_NAME, endpoint);
         Params params = new Params(request)
+            .withWaitForCompletion(waitForCompletion)
             .withRefresh(reindexRequest.isRefresh())
             .withTimeout(reindexRequest.getTimeout())
             .withWaitForActiveShards(reindexRequest.getWaitForActiveShards())
@@ -897,11 +906,8 @@ final class RequestConverters {
             return this;
         }
 
-        Params withWaitForCompletion(boolean waitForCompletion) {
-            if (waitForCompletion) {
-                return putParam("wait_for_completion", Boolean.TRUE.toString());
-            }
-            return this;
+        Params withWaitForCompletion(Boolean waitForCompletion) {
+            return putParam("wait_for_completion", waitForCompletion.toString());
         }
 
         Params withNodes(String[] nodes) {
diff --git a/client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java b/client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java
index 582f917e43b..8b740994e3b 100644
--- a/client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java
+++ b/client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java
@@ -60,6 +60,7 @@ import org.elasticsearch.client.core.CountRequest;
 import org.elasticsearch.client.core.CountResponse;
 import org.elasticsearch.client.core.TermVectorsResponse;
 import org.elasticsearch.client.core.TermVectorsRequest;
+import org.elasticsearch.client.tasks.TaskSubmissionResponse;
 import org.elasticsearch.common.CheckedConsumer;
 import org.elasticsearch.common.CheckedFunction;
 import org.elasticsearch.common.ParseField;
@@ -476,6 +477,20 @@ public class RestHighLevelClient implements Closeable {
         );
     }
 
+    /**
+     * Submits a reindex task.
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html">Reindex API on elastic.co</a>
+     * @param reindexRequest the request
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the submission response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public final TaskSubmissionResponse submitReindexTask(ReindexRequest reindexRequest, RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(
+            reindexRequest, RequestConverters::submitReindex, options, TaskSubmissionResponse::fromXContent, emptySet()
+        );
+    }
+
     /**
      * Asynchronously executes a reindex request.
      * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html">Reindex API on elastic.co</a>
diff --git a/client/rest-high-level/src/main/java/org/elasticsearch/client/tasks/TaskSubmissionResponse.java b/client/rest-high-level/src/main/java/org/elasticsearch/client/tasks/TaskSubmissionResponse.java
new file mode 100644
index 00000000000..7bc104c9bbf
--- /dev/null
+++ b/client/rest-high-level/src/main/java/org/elasticsearch/client/tasks/TaskSubmissionResponse.java
@@ -0,0 +1,78 @@
+/*
+ * 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.client.tasks;
+
+import org.elasticsearch.action.ActionResponse;
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+public class TaskSubmissionResponse extends ActionResponse {
+
+    private static final ParseField TASK = new ParseField("task");
+
+    public static final ConstructingObjectParser<TaskSubmissionResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "task_submission_response",
+        true, a -> new TaskSubmissionResponse((String) a[0]));
+
+    static {
+        PARSER.declareString(ConstructingObjectParser.optionalConstructorArg(), TASK);
+    }
+
+    private final String task;
+
+    TaskSubmissionResponse(String task) {
+        this.task = task;
+    }
+
+    /**
+     * Get the task id
+     *
+     * @return the id of the reindex task.
+     */
+    public String getTask() {
+        return task;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(task);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+        if (other == null || getClass() != other.getClass()) {
+            return false;
+        }
+        TaskSubmissionResponse that = (TaskSubmissionResponse) other;
+        return Objects.equals(task, that.task);
+    }
+
+    public static TaskSubmissionResponse fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+}
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/CrudIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/CrudIT.java
index 1dd27cff0d9..fed0e892156 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/CrudIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/CrudIT.java
@@ -60,8 +60,6 @@ import org.elasticsearch.index.query.IdsQueryBuilder;
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.DeleteByQueryAction;
 import org.elasticsearch.index.reindex.DeleteByQueryRequest;
-import org.elasticsearch.index.reindex.ReindexAction;
-import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryAction;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
 import org.elasticsearch.rest.RestStatus;
@@ -706,111 +704,6 @@ public class CrudIT extends ESRestHighLevelClientTestCase {
         validateBulkResponses(nbItems, errors, bulkResponse, bulkRequest);
     }
 
-    public void testReindex() throws Exception {
-        final String sourceIndex = "source1";
-        final String destinationIndex = "dest";
-        {
-            // Prepare
-            Settings settings = Settings.builder()
-                .put("number_of_shards", 1)
-                .put("number_of_replicas", 0)
-                .build();
-            createIndex(sourceIndex, settings);
-            createIndex(destinationIndex, settings);
-            BulkRequest bulkRequest = new BulkRequest()
-                    .add(new IndexRequest(sourceIndex, "type", "1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON))
-                    .add(new IndexRequest(sourceIndex, "type", "2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
-                    .setRefreshPolicy(RefreshPolicy.IMMEDIATE);
-            assertEquals(
-                RestStatus.OK,
-                highLevelClient().bulk(
-                    bulkRequest,
-                    RequestOptions.DEFAULT
-                ).status()
-            );
-        }
-        {
-            // test1: create one doc in dest
-            ReindexRequest reindexRequest = new ReindexRequest();
-            reindexRequest.setSourceIndices(sourceIndex);
-            reindexRequest.setDestIndex(destinationIndex);
-            reindexRequest.setSourceQuery(new IdsQueryBuilder().addIds("1").types("type"));
-            reindexRequest.setRefresh(true);
-            BulkByScrollResponse bulkResponse = execute(reindexRequest, highLevelClient()::reindex, highLevelClient()::reindexAsync);
-            assertEquals(1, bulkResponse.getCreated());
-            assertEquals(1, bulkResponse.getTotal());
-            assertEquals(0, bulkResponse.getDeleted());
-            assertEquals(0, bulkResponse.getNoops());
-            assertEquals(0, bulkResponse.getVersionConflicts());
-            assertEquals(1, bulkResponse.getBatches());
-            assertTrue(bulkResponse.getTook().getMillis() > 0);
-            assertEquals(1, bulkResponse.getBatches());
-            assertEquals(0, bulkResponse.getBulkFailures().size());
-            assertEquals(0, bulkResponse.getSearchFailures().size());
-        }
-        {
-            // test2: create 1 and update 1
-            ReindexRequest reindexRequest = new ReindexRequest();
-            reindexRequest.setSourceIndices(sourceIndex);
-            reindexRequest.setDestIndex(destinationIndex);
-            BulkByScrollResponse bulkResponse = execute(reindexRequest, highLevelClient()::reindex, highLevelClient()::reindexAsync);
-            assertEquals(1, bulkResponse.getCreated());
-            assertEquals(2, bulkResponse.getTotal());
-            assertEquals(1, bulkResponse.getUpdated());
-            assertEquals(0, bulkResponse.getDeleted());
-            assertEquals(0, bulkResponse.getNoops());
-            assertEquals(0, bulkResponse.getVersionConflicts());
-            assertEquals(1, bulkResponse.getBatches());
-            assertTrue(bulkResponse.getTook().getMillis() > 0);
-            assertEquals(1, bulkResponse.getBatches());
-            assertEquals(0, bulkResponse.getBulkFailures().size());
-            assertEquals(0, bulkResponse.getSearchFailures().size());
-        }
-        {
-            // test reindex rethrottling
-            ReindexRequest reindexRequest = new ReindexRequest();
-            reindexRequest.setSourceIndices(sourceIndex);
-            reindexRequest.setDestIndex(destinationIndex);
-
-            // this following settings are supposed to halt reindexing after first document
-            reindexRequest.setSourceBatchSize(1);
-            reindexRequest.setRequestsPerSecond(0.00001f);
-            final CountDownLatch reindexTaskFinished = new CountDownLatch(1);
-            highLevelClient().reindexAsync(reindexRequest, RequestOptions.DEFAULT, new ActionListener<BulkByScrollResponse>() {
-
-                @Override
-                public void onResponse(BulkByScrollResponse response) {
-                    reindexTaskFinished.countDown();
-                }
-
-                @Override
-                public void onFailure(Exception e) {
-                    fail(e.toString());
-                }
-            });
-
-            TaskId taskIdToRethrottle = findTaskToRethrottle(ReindexAction.NAME);
-            float requestsPerSecond = 1000f;
-            ListTasksResponse response = execute(new RethrottleRequest(taskIdToRethrottle, requestsPerSecond),
-                    highLevelClient()::reindexRethrottle, highLevelClient()::reindexRethrottleAsync);
-            assertThat(response.getTasks(), hasSize(1));
-            assertEquals(taskIdToRethrottle, response.getTasks().get(0).getTaskId());
-            assertThat(response.getTasks().get(0).getStatus(), instanceOf(RawTaskStatus.class));
-            assertEquals(Float.toString(requestsPerSecond),
-                    ((RawTaskStatus) response.getTasks().get(0).getStatus()).toMap().get("requests_per_second").toString());
-            reindexTaskFinished.await(2, TimeUnit.SECONDS);
-
-            // any rethrottling after the reindex is done performed with the same taskId should result in a failure
-            response = execute(new RethrottleRequest(taskIdToRethrottle, requestsPerSecond),
-                    highLevelClient()::reindexRethrottle, highLevelClient()::reindexRethrottleAsync);
-            assertTrue(response.getTasks().isEmpty());
-            assertFalse(response.getNodeFailures().isEmpty());
-            assertEquals(1, response.getNodeFailures().size());
-            assertEquals("Elasticsearch exception [type=resource_not_found_exception, reason=task [" + taskIdToRethrottle + "] is missing]",
-                    response.getNodeFailures().get(0).getCause().getMessage());
-        }
-    }
-
     private TaskId findTaskToRethrottle(String actionName) throws IOException {
         long start = System.nanoTime();
         ListTasksRequest request = new ListTasksRequest();
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/ReindexIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/ReindexIT.java
new file mode 100644
index 00000000000..afc5e99b5f0
--- /dev/null
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/ReindexIT.java
@@ -0,0 +1,133 @@
+/*
+ * 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.client;
+
+import org.elasticsearch.action.bulk.BulkRequest;
+import org.elasticsearch.action.index.IndexRequest;
+import org.elasticsearch.action.support.WriteRequest;
+import org.elasticsearch.client.tasks.TaskSubmissionResponse;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.index.query.IdsQueryBuilder;
+import org.elasticsearch.index.reindex.BulkByScrollResponse;
+import org.elasticsearch.index.reindex.ReindexRequest;
+import org.elasticsearch.rest.RestStatus;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.function.BooleanSupplier;
+
+public class ReindexIT extends ESRestHighLevelClientTestCase {
+
+    public void testReindex() throws IOException {
+        final String sourceIndex = "source1";
+        final String destinationIndex = "dest";
+        {
+            // Prepare
+            Settings settings = Settings.builder()
+                .put("number_of_shards", 1)
+                .put("number_of_replicas", 0)
+                .build();
+            createIndex(sourceIndex, settings);
+            createIndex(destinationIndex, settings);
+            BulkRequest bulkRequest = new BulkRequest()
+                .add(new IndexRequest(sourceIndex, "type", "1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON))
+                .add(new IndexRequest(sourceIndex, "type", "2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
+            assertEquals(
+                RestStatus.OK,
+                highLevelClient().bulk(
+                    bulkRequest,
+                    RequestOptions.DEFAULT
+                ).status()
+            );
+        }
+        {
+            // reindex one document with id 1 from source to destination
+            ReindexRequest reindexRequest = new ReindexRequest();
+            reindexRequest.setSourceIndices(sourceIndex);
+            reindexRequest.setDestIndex(destinationIndex);
+            reindexRequest.setSourceQuery(new IdsQueryBuilder().addIds("1").types("type"));
+            reindexRequest.setRefresh(true);
+
+            BulkByScrollResponse bulkResponse = execute(reindexRequest, highLevelClient()::reindex, highLevelClient()::reindexAsync);
+
+            assertEquals(1, bulkResponse.getCreated());
+            assertEquals(1, bulkResponse.getTotal());
+            assertEquals(0, bulkResponse.getDeleted());
+            assertEquals(0, bulkResponse.getNoops());
+            assertEquals(0, bulkResponse.getVersionConflicts());
+            assertEquals(1, bulkResponse.getBatches());
+            assertTrue(bulkResponse.getTook().getMillis() > 0);
+            assertEquals(1, bulkResponse.getBatches());
+            assertEquals(0, bulkResponse.getBulkFailures().size());
+            assertEquals(0, bulkResponse.getSearchFailures().size());
+        }
+    }
+
+    public void testReindexTask() throws IOException, InterruptedException {
+        final String sourceIndex = "source123";
+        final String destinationIndex = "dest2";
+        {
+            // Prepare
+            Settings settings = Settings.builder()
+                .put("number_of_shards", 1)
+                .put("number_of_replicas", 0)
+                .build();
+            createIndex(sourceIndex, settings);
+            createIndex(destinationIndex, settings);
+            BulkRequest bulkRequest = new BulkRequest()
+                .add(new IndexRequest(sourceIndex, "type", "1").source(Collections.singletonMap("foo", "bar"), XContentType.JSON))
+                .add(new IndexRequest(sourceIndex, "type", "2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
+            assertEquals(
+                RestStatus.OK,
+                highLevelClient().bulk(
+                    bulkRequest,
+                    RequestOptions.DEFAULT
+                ).status()
+            );
+        }
+        {
+            ReindexRequest reindexRequest = new ReindexRequest();
+            reindexRequest.setSourceIndices(sourceIndex);
+            reindexRequest.setDestIndex(destinationIndex);
+            reindexRequest.setSourceQuery(new IdsQueryBuilder().addIds("1").types("type"));
+            reindexRequest.setRefresh(true);
+
+            TaskSubmissionResponse reindexSubmission = highLevelClient().submitReindexTask(reindexRequest, RequestOptions.DEFAULT);
+
+            BooleanSupplier hasUpgradeCompleted = checkCompletionStatus(reindexSubmission.getTask());
+            awaitBusy(hasUpgradeCompleted);
+        }
+    }
+
+    private BooleanSupplier checkCompletionStatus(String taskId) {
+        return () -> {
+            try {
+                Response response = client().performRequest(new Request("GET", "/_tasks/" + taskId));
+                return (boolean) entityAsMap(response).get("completed");
+            } catch (IOException e) {
+                fail(e.getMessage());
+                return false;
+            }
+        };
+    }
+}
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java
index 066fb5d8cc9..20419ac314a 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java
@@ -348,6 +348,7 @@ public class RequestConvertersTests extends ESTestCase {
         setRandomTimeout(reindexRequest::setTimeout, ReplicationRequest.DEFAULT_TIMEOUT, expectedParams);
         setRandomWaitForActiveShards(reindexRequest::setWaitForActiveShards, ActiveShardCount.DEFAULT, expectedParams);
         expectedParams.put("scroll", reindexRequest.getScrollTime().getStringRep());
+        expectedParams.put("wait_for_completion", Boolean.TRUE.toString());
         Request request = RequestConverters.reindex(reindexRequest);
         assertEquals("/_reindex", request.getEndpoint());
         assertEquals(HttpPost.METHOD_NAME, request.getMethod());
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java
index dfb9848126d..4c7e8790ed6 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java
@@ -83,6 +83,7 @@ import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.InternalAggregationTestCase;
 import org.elasticsearch.test.rest.yaml.restspec.ClientYamlSuiteRestApi;
 import org.elasticsearch.test.rest.yaml.restspec.ClientYamlSuiteRestSpec;
+import org.hamcrest.Matchers;
 import org.junit.Before;
 
 import java.io.IOException;
@@ -114,6 +115,8 @@ import static org.mockito.Mockito.when;
 
 public class RestHighLevelClientTests extends ESTestCase {
 
+    private static final String SUBMIT_TASK_PREFIX = "submit_";
+    private static final String SUBMIT_TASK_SUFFIX = "_task";
     private static final ProtocolVersion HTTP_PROTOCOL = new ProtocolVersion("http", 1, 1);
     private static final RequestLine REQUEST_LINE = new BasicRequestLine(HttpGet.METHOD_NAME, "/", HTTP_PROTOCOL);
 
@@ -728,47 +731,11 @@ public class RestHighLevelClientTests extends ESTestCase {
 
             //we convert all the method names to snake case, hence we need to look for the '_async' suffix rather than 'Async'
             if (apiName.endsWith("_async")) {
-                assertTrue("async method [" + method.getName() + "] doesn't have corresponding sync method",
-                        methods.containsKey(apiName.substring(0, apiName.length() - 6)));
-                assertThat("async method [" + method + "] should return void", method.getReturnType(), equalTo(Void.TYPE));
-                assertEquals("async method [" + method + "] should not throw any exceptions", 0, method.getExceptionTypes().length);
-                if (apiName.equals("security.authenticate_async") || apiName.equals("security.get_ssl_certificates_async")) {
-                    assertEquals(2, method.getParameterTypes().length);
-                    assertThat(method.getParameterTypes()[0], equalTo(RequestOptions.class));
-                    assertThat(method.getParameterTypes()[1], equalTo(ActionListener.class));
-                } else {
-                    assertEquals("async method [" + method + "] has the wrong number of arguments", 3, method.getParameterTypes().length);
-                    assertThat("the first parameter to async method [" + method + "] should be a request type",
-                        method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
-                    assertThat("the second parameter to async method [" + method + "] is the wrong type",
-                        method.getParameterTypes()[1], equalTo(RequestOptions.class));
-                    assertThat("the third parameter to async method [" + method + "] is the wrong type",
-                        method.getParameterTypes()[2], equalTo(ActionListener.class));
-                }
+                assertAsyncMethod(methods, method, apiName);
+            } else if (isSubmitTaskMethod(apiName)) {
+                assertSubmitTaskMethod(methods, method, apiName, restSpec);
             } else {
-                //A few methods return a boolean rather than a response object
-                if (apiName.equals("ping") || apiName.contains("exist")) {
-                    assertThat("the return type for method [" + method + "] is incorrect",
-                        method.getReturnType().getSimpleName(), equalTo("boolean"));
-                } else {
-                    assertThat("the return type for method [" + method + "] is incorrect",
-                        method.getReturnType().getSimpleName(), endsWith("Response"));
-                }
-
-                assertEquals("incorrect number of exceptions for method [" + method + "]", 1, method.getExceptionTypes().length);
-                //a few methods don't accept a request object as argument
-                if (apiName.equals("ping") || apiName.equals("info") || apiName.equals("security.get_ssl_certificates")
-                    || apiName.equals("security.authenticate")) {
-                    assertEquals("incorrect number of arguments for method [" + method + "]", 1, method.getParameterTypes().length);
-                    assertThat("the parameter to method [" + method + "] is the wrong type",
-                        method.getParameterTypes()[0], equalTo(RequestOptions.class));
-                } else {
-                    assertEquals("incorrect number of arguments for method [" + method + "]", 2, method.getParameterTypes().length);
-                    assertThat("the first parameter to method [" + method + "] is the wrong type",
-                        method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
-                    assertThat("the second parameter to method [" + method + "] is the wrong type",
-                        method.getParameterTypes()[1], equalTo(RequestOptions.class));
-                }
+                assertSyncMethod(method, apiName);
 
                 boolean remove = apiSpec.remove(apiName);
                 if (remove == false) {
@@ -804,6 +771,74 @@ public class RestHighLevelClientTests extends ESTestCase {
         assertThat("Some API are not supported but they should be: " + apiSpec, apiSpec.size(), equalTo(0));
     }
 
+    private void assertSyncMethod(Method method, String apiName) {
+        //A few methods return a boolean rather than a response object
+        if (apiName.equals("ping") || apiName.contains("exist")) {
+            assertThat("the return type for method [" + method + "] is incorrect",
+                method.getReturnType().getSimpleName(), equalTo("boolean"));
+        } else {
+            assertThat("the return type for method [" + method + "] is incorrect",
+                method.getReturnType().getSimpleName(), endsWith("Response"));
+        }
+
+        assertEquals("incorrect number of exceptions for method [" + method + "]", 1, method.getExceptionTypes().length);
+        //a few methods don't accept a request object as argument
+        if (apiName.equals("ping") || apiName.equals("info") || apiName.equals("security.get_ssl_certificates")
+            || apiName.equals("security.authenticate")) {
+            assertEquals("incorrect number of arguments for method [" + method + "]", 1, method.getParameterTypes().length);
+            assertThat("the parameter to method [" + method + "] is the wrong type",
+                method.getParameterTypes()[0], equalTo(RequestOptions.class));
+        } else {
+            assertEquals("incorrect number of arguments for method [" + method + "]", 2, method.getParameterTypes().length);
+            assertThat("the first parameter to method [" + method + "] is the wrong type",
+                method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
+            assertThat("the second parameter to method [" + method + "] is the wrong type",
+                method.getParameterTypes()[1], equalTo(RequestOptions.class));
+        }
+    }
+
+    private void assertAsyncMethod(Map<String, Method> methods, Method method, String apiName) {
+        assertTrue("async method [" + method.getName() + "] doesn't have corresponding sync method",
+                methods.containsKey(apiName.substring(0, apiName.length() - 6)));
+        assertThat("async method [" + method + "] should return void", method.getReturnType(), equalTo(Void.TYPE));
+        assertEquals("async method [" + method + "] should not throw any exceptions", 0, method.getExceptionTypes().length);
+        if (apiName.equals("security.authenticate_async") || apiName.equals("security.get_ssl_certificates_async")) {
+            assertEquals(2, method.getParameterTypes().length);
+            assertThat(method.getParameterTypes()[0], equalTo(RequestOptions.class));
+            assertThat(method.getParameterTypes()[1], equalTo(ActionListener.class));
+        } else {
+            assertEquals("async method [" + method + "] has the wrong number of arguments", 3, method.getParameterTypes().length);
+            assertThat("the first parameter to async method [" + method + "] should be a request type",
+                method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
+            assertThat("the second parameter to async method [" + method + "] is the wrong type",
+                method.getParameterTypes()[1], equalTo(RequestOptions.class));
+            assertThat("the third parameter to async method [" + method + "] is the wrong type",
+                method.getParameterTypes()[2], equalTo(ActionListener.class));
+        }
+    }
+
+    private void assertSubmitTaskMethod(Map<String, Method> methods, Method method, String apiName, ClientYamlSuiteRestSpec restSpec) {
+        String methodName = extractMethodName(apiName);
+        assertTrue("submit task method [" + method.getName() + "] doesn't have corresponding sync method",
+            methods.containsKey(methodName));
+        assertEquals("submit task method [" + method + "] has the wrong number of arguments", 2, method.getParameterTypes().length);
+        assertThat("the first parameter to submit task method [" + method + "] is the wrong type",
+            method.getParameterTypes()[0].getSimpleName(), endsWith("Request"));
+        assertThat("the second parameter to submit task method [" + method + "] is the wrong type",
+            method.getParameterTypes()[1], equalTo(RequestOptions.class));
+
+        assertThat("submit task method [" + method + "] must have wait_for_completion parameter in rest spec",
+            restSpec.getApi(methodName).getParams(), Matchers.hasKey("wait_for_completion"));
+    }
+
+    private String extractMethodName(String apiName) {
+        return apiName.substring(SUBMIT_TASK_PREFIX.length(), apiName.length() - SUBMIT_TASK_SUFFIX.length());
+    }
+
+    private boolean isSubmitTaskMethod(String apiName) {
+        return apiName.startsWith(SUBMIT_TASK_PREFIX) && apiName.endsWith(SUBMIT_TASK_SUFFIX);
+    }
+
     private static Stream<Tuple<String, Method>> getSubClientMethods(String namespace, Class<?> clientClass) {
         return Arrays.stream(clientClass.getMethods()).filter(method -> method.getDeclaringClass().equals(clientClass))
                 .map(method -> Tuple.tuple(namespace + "." + toSnakeCase(method.getName()), method))
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/SnapshotRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/SnapshotRequestConvertersTests.java
index efd321aa7ee..ca86a912042 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/SnapshotRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/SnapshotRequestConvertersTests.java
@@ -51,7 +51,7 @@ import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
 
 public class SnapshotRequestConvertersTests extends ESTestCase {
-    
+
     public void testGetRepositories() {
         Map<String, String> expectedParams = new HashMap<>();
         StringBuilder endpoint = new StringBuilder("/_snapshot");
@@ -61,14 +61,14 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         RequestConvertersTests.setRandomLocal(getRepositoriesRequest, expectedParams);
 
         if (randomBoolean()) {
-            String[] entries = new String[] { "a", "b", "c" };
+            String[] entries = new String[]{"a", "b", "c"};
             getRepositoriesRequest.repositories(entries);
             endpoint.append("/" + String.join(",", entries));
         }
 
         Request request = SnapshotRequestConverters.getRepositories(getRepositoriesRequest);
-        assertThat(endpoint.toString(), equalTo(request.getEndpoint()));
-        assertThat(HttpGet.METHOD_NAME, equalTo(request.getMethod()));
+        assertThat(request.getEndpoint(), equalTo(endpoint.toString()));
+        assertThat(request.getMethod(), equalTo(HttpGet.METHOD_NAME));
         assertThat(expectedParams, equalTo(request.getParameters()));
     }
 
@@ -88,8 +88,8 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
                 .build());
 
         Request request = SnapshotRequestConverters.createRepository(putRepositoryRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpPut.METHOD_NAME, equalTo(request.getMethod()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpPut.METHOD_NAME));
         RequestConvertersTests.assertToXContentBody(putRepositoryRequest, request.getEntity());
     }
 
@@ -105,9 +105,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         RequestConvertersTests.setRandomTimeout(deleteRepositoryRequest::timeout, AcknowledgedRequest.DEFAULT_ACK_TIMEOUT, expectedParams);
 
         Request request = SnapshotRequestConverters.deleteRepository(deleteRepositoryRequest);
-        assertThat(endpoint.toString(), equalTo(request.getEndpoint()));
-        assertThat(HttpDelete.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint.toString()));
+        assertThat(request.getMethod(), equalTo(HttpDelete.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         assertNull(request.getEntity());
     }
 
@@ -121,9 +121,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         RequestConvertersTests.setRandomTimeout(verifyRepositoryRequest::timeout, AcknowledgedRequest.DEFAULT_ACK_TIMEOUT, expectedParams);
 
         Request request = SnapshotRequestConverters.verifyRepository(verifyRepositoryRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpPost.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpPost.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
     }
 
     public void testCreateSnapshot() throws IOException {
@@ -137,14 +137,12 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         Boolean waitForCompletion = randomBoolean();
         createSnapshotRequest.waitForCompletion(waitForCompletion);
 
-        if (waitForCompletion) {
-            expectedParams.put("wait_for_completion", waitForCompletion.toString());
-        }
+        expectedParams.put("wait_for_completion", waitForCompletion.toString());
 
         Request request = SnapshotRequestConverters.createSnapshot(createSnapshotRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpPut.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpPut.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         RequestConvertersTests.assertToXContentBody(createSnapshotRequest, request.getEntity());
     }
 
@@ -178,9 +176,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         }
 
         Request request = SnapshotRequestConverters.getSnapshots(getSnapshotsRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpGet.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpGet.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         assertNull(request.getEntity());
     }
 
@@ -202,9 +200,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         expectedParams.put("verbose", Boolean.toString(verbose));
 
         Request request = SnapshotRequestConverters.getSnapshots(getSnapshotsRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpGet.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpGet.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         assertNull(request.getEntity());
     }
 
@@ -239,10 +237,10 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
 
         RestoreSnapshotRequest restoreSnapshotRequest = new RestoreSnapshotRequest(repository, snapshot);
         RequestConvertersTests.setRandomMasterTimeout(restoreSnapshotRequest, expectedParams);
-        if (randomBoolean()) {
-            restoreSnapshotRequest.waitForCompletion(true);
-            expectedParams.put("wait_for_completion", "true");
-        }
+        boolean waitForCompletion = randomBoolean();
+        restoreSnapshotRequest.waitForCompletion(waitForCompletion);
+        expectedParams.put("wait_for_completion", Boolean.toString(waitForCompletion));
+
         if (randomBoolean()) {
             String timeout = randomTimeValue();
             restoreSnapshotRequest.masterNodeTimeout(timeout);
@@ -250,9 +248,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         }
 
         Request request = SnapshotRequestConverters.restoreSnapshot(restoreSnapshotRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpPost.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpPost.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         RequestConvertersTests.assertToXContentBody(restoreSnapshotRequest, request.getEntity());
     }
 
@@ -269,9 +267,9 @@ public class SnapshotRequestConvertersTests extends ESTestCase {
         RequestConvertersTests.setRandomMasterTimeout(deleteSnapshotRequest, expectedParams);
 
         Request request = SnapshotRequestConverters.deleteSnapshot(deleteSnapshotRequest);
-        assertThat(endpoint, equalTo(request.getEndpoint()));
-        assertThat(HttpDelete.METHOD_NAME, equalTo(request.getMethod()));
-        assertThat(expectedParams, equalTo(request.getParameters()));
+        assertThat(request.getEndpoint(), equalTo(endpoint));
+        assertThat(request.getMethod(), equalTo(HttpDelete.METHOD_NAME));
+        assertThat(request.getParameters(), equalTo(expectedParams));
         assertNull(request.getEntity());
     }
 }
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksRequestConvertersTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksRequestConvertersTests.java
index ff6726faee1..4b7889d3b7e 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksRequestConvertersTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksRequestConvertersTests.java
@@ -62,12 +62,10 @@ public class TasksRequestConvertersTests extends ESTestCase {
                     expectedParams.put("detailed", "true");
                 }
             }
-            if (randomBoolean()) {
-                request.setWaitForCompletion(randomBoolean());
-                if (request.getWaitForCompletion()) {
-                    expectedParams.put("wait_for_completion", "true");
-                }
-            }
+
+            request.setWaitForCompletion(randomBoolean());
+            expectedParams.put("wait_for_completion", Boolean.toString(request.getWaitForCompletion()));
+
             if (randomBoolean()) {
                 String timeout = randomTimeValue();
                 request.setTimeout(timeout);
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/tasks/TaskSubmissionResponseTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/tasks/TaskSubmissionResponseTests.java
new file mode 100644
index 00000000000..4e21b28dd81
--- /dev/null
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/tasks/TaskSubmissionResponseTests.java
@@ -0,0 +1,51 @@
+/*
+ * 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.client.tasks;
+
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+
+import static org.elasticsearch.test.AbstractXContentTestCase.xContentTester;
+
+public class TaskSubmissionResponseTests extends ESTestCase {
+
+    public void testFromXContent() throws IOException {
+        xContentTester(
+            this::createParser,
+            this::createTestInstance,
+            this::toXContent,
+            TaskSubmissionResponse::fromXContent)
+            .supportsUnknownFields(true)
+            .test();
+    }
+
+    private void toXContent(TaskSubmissionResponse response, XContentBuilder xContentBuilder) throws IOException {
+        xContentBuilder.startObject();
+        xContentBuilder.field("task", response.getTask());
+        xContentBuilder.endObject();
+    }
+
+    private TaskSubmissionResponse createTestInstance() {
+        String taskId = randomAlphaOfLength(5) + ":" + randomLong();
+        return new TaskSubmissionResponse(taskId);
+    }
+}