diff --git a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
index 6ace2998698b..fa6da27a72bd 100644
--- a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
+++ b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
@@ -33,8 +33,9 @@
 
 package com.google.gcloud.pubsub.spi.v1;
 
-import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable;
+import com.google.api.gax.grpc.ApiCallable.BundlableApiCallableInfo;
+import com.google.api.gax.grpc.BundlerFactory;
 import com.google.api.gax.protobuf.PathTemplate;
 import com.google.protobuf.Empty;
 import com.google.pubsub.v1.DeleteTopicRequest;
@@ -65,9 +66,25 @@
  */
 @javax.annotation.Generated("by GAPIC")
 public class PublisherApi implements AutoCloseable {
+  // ========
+  // Members
+  // ========
+
+  private final ManagedChannel channel;
+  private final List<AutoCloseable> closeables = new ArrayList<>();
+
+  private final ApiCallable<Topic, Topic> createTopicCallable;
+  private final ApiCallable<PublishRequest, PublishResponse> publishCallable;
+  private final ApiCallable<GetTopicRequest, Topic> getTopicCallable;
+  private final ApiCallable<ListTopicsRequest, ListTopicsResponse> listTopicsCallable;
+  private final ApiCallable<ListTopicsRequest, Iterable<Topic>> listTopicsIterableCallable;
+  private final ApiCallable<ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse>
+      listTopicSubscriptionsCallable;
+  private final ApiCallable<ListTopicSubscriptionsRequest, Iterable<String>>
+      listTopicSubscriptionsIterableCallable;
+  private final ApiCallable<DeleteTopicRequest, Empty> deleteTopicCallable;
 
   public static class ResourceNames {
-    private ResourceNames() {}
 
     // =======================
     // ResourceNames Constants
@@ -93,6 +110,8 @@ private ResourceNames() {}
     private static final PathTemplate TOPIC_PATH_TEMPLATE =
         PathTemplate.create("projects/{project}/topics/{topic}");
 
+    private ResourceNames() {}
+
     // ==============================
     // Resource Name Helper Functions
     // ==============================
@@ -153,24 +172,6 @@ public static final String parseTopicFromTopicPath(String topicPath) {
     }
   }
 
-  // ========
-  // Members
-  // ========
-
-  private final ManagedChannel channel;
-  private final List<AutoCloseable> closeables = new ArrayList<>();
-
-  private final ApiCallable<Topic, Topic> createTopicCallable;
-  private final ApiCallable<PublishRequest, PublishResponse> publishCallable;
-  private final ApiCallable<GetTopicRequest, Topic> getTopicCallable;
-  private final ApiCallable<ListTopicsRequest, ListTopicsResponse> listTopicsCallable;
-  private final ApiCallable<ListTopicsRequest, Iterable<Topic>> listTopicsIterableCallable;
-  private final ApiCallable<ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse>
-      listTopicSubscriptionsCallable;
-  private final ApiCallable<ListTopicSubscriptionsRequest, Iterable<String>>
-      listTopicSubscriptionsIterableCallable;
-  private final ApiCallable<DeleteTopicRequest, Empty> deleteTopicCallable;
-
   // ===============
   // Factory Methods
   // ===============
@@ -186,8 +187,9 @@ public static PublisherApi create() throws IOException {
   }
 
   /**
-   * Constructs an instance of PublisherApi, using the given settings. The channels are created based
-   * on the settings passed in, or defaults for any settings that are not set.
+   * Constructs an instance of PublisherApi, using the given settings.
+   * The channels are created based on the settings passed in, or defaults for any
+   * settings that are not set.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -197,8 +199,9 @@ public static PublisherApi create(PublisherSettings settings) throws IOException
   }
 
   /**
-   * Constructs an instance of PublisherApi, using the given settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of PublisherApi, using the given settings.
+   * This is protected so that it easy to make a subclass, but otherwise, the static
+   * factory methods should be preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -207,7 +210,14 @@ protected PublisherApi(PublisherSettings settings) throws IOException {
     this.channel = settings.getChannel();
 
     this.createTopicCallable = settings.createTopicMethod().build(settings);
-    this.publishCallable = settings.publishMethod().build(settings);
+    BundlableApiCallableInfo<PublishRequest, PublishResponse> bundlablePublish =
+        settings.publishMethod().buildBundlable(settings);
+    this.publishCallable = bundlablePublish.getApiCallable();
+    BundlerFactory<PublishRequest, PublishResponse> publishBundlerFactory =
+        bundlablePublish.getBundlerFactory();
+    if (publishBundlerFactory != null) {
+      this.closeables.add(publishBundlerFactory);
+    }
     this.getTopicCallable = settings.getTopicMethod().build(settings);
     this.listTopicsCallable = settings.listTopicsMethod().build(settings);
     this.listTopicsIterableCallable = settings.listTopicsMethod().buildPageStreaming(settings);
diff --git a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
index 70b188735890..11566404546f 100644
--- a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
+++ b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
@@ -38,8 +38,11 @@
 import com.google.api.gax.core.RetryParams;
 import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable.ApiCallableBuilder;
+import com.google.api.gax.grpc.ApiCallable.BundlableApiCallableBuilder;
 import com.google.api.gax.grpc.ApiCallable.PageStreamingApiCallableBuilder;
-import com.google.api.gax.grpc.PageDescriptor;
+import com.google.api.gax.grpc.BundlingDescriptor;
+import com.google.api.gax.grpc.PageStreamingDescriptor;
+import com.google.api.gax.grpc.RequestIssuer;
 import com.google.api.gax.grpc.ServiceApiSettings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -56,8 +59,12 @@
 import com.google.pubsub.v1.PublishRequest;
 import com.google.pubsub.v1.PublishResponse;
 import com.google.pubsub.v1.PublisherGrpc;
+import com.google.pubsub.v1.PubsubMessage;
 import com.google.pubsub.v1.Topic;
 import io.grpc.Status;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 
 // Manually-added imports: add custom (non-generated) imports after this point.
 
@@ -132,9 +139,11 @@ public class PublisherSettings extends ServiceApiSettings {
     RETRY_PARAM_DEFINITIONS = definitions.build();
   }
 
+  private final MethodBuilders methods;
+
   private static class MethodBuilders {
     private final ApiCallableBuilder<Topic, Topic> createTopicMethod;
-    private final ApiCallableBuilder<PublishRequest, PublishResponse> publishMethod;
+    private final BundlableApiCallableBuilder<PublishRequest, PublishResponse> publishMethod;
     private final ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod;
     private final PageStreamingApiCallableBuilder<ListTopicsRequest, ListTopicsResponse, Topic>
         listTopicsMethod;
@@ -149,7 +158,8 @@ public MethodBuilders() {
       createTopicMethod.setRetryableCodes(RETRYABLE_CODE_DEFINITIONS.get("idempotent"));
       createTopicMethod.setRetryParams(RETRY_PARAM_DEFINITIONS.get("default"));
 
-      publishMethod = new ApiCallableBuilder<>(PublisherGrpc.METHOD_PUBLISH);
+      publishMethod =
+          new BundlableApiCallableBuilder<>(PublisherGrpc.METHOD_PUBLISH, PUBLISH_BUNDLING_DESC);
       publishMethod.setRetryableCodes(RETRYABLE_CODE_DEFINITIONS.get("non_idempotent"));
       publishMethod.setRetryParams(RETRY_PARAM_DEFINITIONS.get("default"));
 
@@ -187,8 +197,6 @@ public MethodBuilders() {
     }
   }
 
-  private final MethodBuilders methods;
-
   // ===============
   // Factory Methods
   // ===============
@@ -211,8 +219,9 @@ public static PublisherSettings create() {
   }
 
   /**
-   * Constructs an instance of PublisherSettings with default settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of PublisherSettings with default settings. This is protected
+   * so that it easy to make a subclass, but otherwise, the static factory methods should be
+   * preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -223,7 +232,7 @@ protected PublisherSettings(MethodBuilders methods) {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method createTopic.
+   * Returns the builder for the API method createTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -233,17 +242,17 @@ public ApiCallableBuilder<Topic, Topic> createTopicMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method publish.
+   * Returns the builder for the API method publish.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
    */
-  public ApiCallableBuilder<PublishRequest, PublishResponse> publishMethod() {
+  public BundlableApiCallableBuilder<PublishRequest, PublishResponse> publishMethod() {
     return methods.publishMethod;
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method getTopic.
+   * Returns the builder for the API method getTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -253,7 +262,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listTopics.
+   * Returns the builder for the API method listTopics.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -264,7 +273,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listTopicSubscriptions.
+   * Returns the builder for the API method listTopicSubscriptions.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -276,7 +285,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method deleteTopic.
+   * Returns the builder for the API method deleteTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -285,9 +294,9 @@ public ApiCallableBuilder<DeleteTopicRequest, Empty> deleteTopicMethod() {
     return methods.deleteTopicMethod;
   }
 
-  private static PageDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>
+  private static PageStreamingDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>
       LIST_TOPICS_PAGE_STR_DESC =
-          new PageDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>() {
+          new PageStreamingDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>() {
             @Override
             public Object emptyToken() {
               return "";
@@ -309,10 +318,10 @@ public Iterable<Topic> extractResources(ListTopicsResponse payload) {
             }
           };
 
-  private static PageDescriptor<
+  private static PageStreamingDescriptor<
           ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse, String>
       LIST_TOPIC_SUBSCRIPTIONS_PAGE_STR_DESC =
-          new PageDescriptor<
+          new PageStreamingDescriptor<
               ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse, String>() {
             @Override
             public Object emptyToken() {
@@ -337,4 +346,66 @@ public Iterable<String> extractResources(ListTopicSubscriptionsResponse payload)
               return payload.getSubscriptionsList();
             }
           };
+
+  private static BundlingDescriptor<PublishRequest, PublishResponse> PUBLISH_BUNDLING_DESC =
+      new BundlingDescriptor<PublishRequest, PublishResponse>() {
+        @Override
+        public String getBundlePartitionKey(PublishRequest request) {
+          return request.getTopic();
+        }
+
+        @Override
+        public PublishRequest mergeRequests(Collection<PublishRequest> requests) {
+          PublishRequest firstRequest = requests.iterator().next();
+
+          List<PubsubMessage> elements = new ArrayList<>();
+          for (PublishRequest request : requests) {
+            elements.addAll(request.getMessagesList());
+          }
+
+          PublishRequest bundleRequest =
+              PublishRequest.newBuilder()
+                  .setTopic(firstRequest.getTopic())
+                  .addAllMessages(elements)
+                  .build();
+          return bundleRequest;
+        }
+
+        @Override
+        public void splitResponse(
+            PublishResponse bundleResponse,
+            Collection<? extends RequestIssuer<PublishRequest, PublishResponse>> bundle) {
+          int bundleMessageIndex = 0;
+          for (RequestIssuer<PublishRequest, PublishResponse> responder : bundle) {
+            List<String> subresponseElements = new ArrayList<>();
+            int subresponseCount = responder.getRequest().getMessagesCount();
+            for (int i = 0; i < subresponseCount; i++) {
+              subresponseElements.add(bundleResponse.getMessageIds(bundleMessageIndex));
+              bundleMessageIndex += 1;
+            }
+            PublishResponse response =
+                PublishResponse.newBuilder().addAllMessageIds(subresponseElements).build();
+            responder.setResponse(response);
+          }
+        }
+
+        @Override
+        public void splitException(
+            Throwable throwable,
+            Collection<? extends RequestIssuer<PublishRequest, PublishResponse>> bundle) {
+          for (RequestIssuer<PublishRequest, PublishResponse> responder : bundle) {
+            responder.setException(throwable);
+          }
+        }
+
+        @Override
+        public long countElements(PublishRequest request) {
+          return request.getMessagesCount();
+        }
+
+        @Override
+        public long countBytes(PublishRequest request) {
+          return request.getSerializedSize();
+        }
+      };
 }
diff --git a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
index 16e1435b8582..d53dca7f8885 100644
--- a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
+++ b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
@@ -33,7 +33,6 @@
 
 package com.google.gcloud.pubsub.spi.v1;
 
-import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable;
 import com.google.api.gax.protobuf.PathTemplate;
 import com.google.protobuf.Empty;
@@ -66,9 +65,26 @@
  */
 @javax.annotation.Generated("by GAPIC")
 public class SubscriberApi implements AutoCloseable {
+  // ========
+  // Members
+  // ========
+
+  private final ManagedChannel channel;
+  private final List<AutoCloseable> closeables = new ArrayList<>();
+
+  private final ApiCallable<Subscription, Subscription> createSubscriptionCallable;
+  private final ApiCallable<GetSubscriptionRequest, Subscription> getSubscriptionCallable;
+  private final ApiCallable<ListSubscriptionsRequest, ListSubscriptionsResponse>
+      listSubscriptionsCallable;
+  private final ApiCallable<ListSubscriptionsRequest, Iterable<Subscription>>
+      listSubscriptionsIterableCallable;
+  private final ApiCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionCallable;
+  private final ApiCallable<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineCallable;
+  private final ApiCallable<AcknowledgeRequest, Empty> acknowledgeCallable;
+  private final ApiCallable<PullRequest, PullResponse> pullCallable;
+  private final ApiCallable<ModifyPushConfigRequest, Empty> modifyPushConfigCallable;
 
   public static class ResourceNames {
-    private ResourceNames() {}
 
     // =======================
     // ResourceNames Constants
@@ -94,6 +110,8 @@ private ResourceNames() {}
     private static final PathTemplate SUBSCRIPTION_PATH_TEMPLATE =
         PathTemplate.create("projects/{project}/subscriptions/{subscription}");
 
+    private ResourceNames() {}
+
     // ==============================
     // Resource Name Helper Functions
     // ==============================
@@ -155,25 +173,6 @@ public static final String parseSubscriptionFromSubscriptionPath(String subscrip
     }
   }
 
-  // ========
-  // Members
-  // ========
-
-  private final ManagedChannel channel;
-  private final List<AutoCloseable> closeables = new ArrayList<>();
-
-  private final ApiCallable<Subscription, Subscription> createSubscriptionCallable;
-  private final ApiCallable<GetSubscriptionRequest, Subscription> getSubscriptionCallable;
-  private final ApiCallable<ListSubscriptionsRequest, ListSubscriptionsResponse>
-      listSubscriptionsCallable;
-  private final ApiCallable<ListSubscriptionsRequest, Iterable<Subscription>>
-      listSubscriptionsIterableCallable;
-  private final ApiCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionCallable;
-  private final ApiCallable<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineCallable;
-  private final ApiCallable<AcknowledgeRequest, Empty> acknowledgeCallable;
-  private final ApiCallable<PullRequest, PullResponse> pullCallable;
-  private final ApiCallable<ModifyPushConfigRequest, Empty> modifyPushConfigCallable;
-
   // ===============
   // Factory Methods
   // ===============
@@ -189,8 +188,9 @@ public static SubscriberApi create() throws IOException {
   }
 
   /**
-   * Constructs an instance of SubscriberApi, using the given settings. The channels are created based
-   * on the settings passed in, or defaults for any settings that are not set.
+   * Constructs an instance of SubscriberApi, using the given settings.
+   * The channels are created based on the settings passed in, or defaults for any
+   * settings that are not set.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -200,8 +200,9 @@ public static SubscriberApi create(SubscriberSettings settings) throws IOExcepti
   }
 
   /**
-   * Constructs an instance of SubscriberApi, using the given settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of SubscriberApi, using the given settings.
+   * This is protected so that it easy to make a subclass, but otherwise, the static
+   * factory methods should be preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
diff --git a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
index 2680d8429938..d9da44aa81f7 100644
--- a/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
+++ b/gcloud-java-pubsub/baseline/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
@@ -39,7 +39,7 @@
 import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable.ApiCallableBuilder;
 import com.google.api.gax.grpc.ApiCallable.PageStreamingApiCallableBuilder;
-import com.google.api.gax.grpc.PageDescriptor;
+import com.google.api.gax.grpc.PageStreamingDescriptor;
 import com.google.api.gax.grpc.ServiceApiSettings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -133,6 +133,8 @@ public class SubscriberSettings extends ServiceApiSettings {
     RETRY_PARAM_DEFINITIONS = definitions.build();
   }
 
+  private final MethodBuilders methods;
+
   private static class MethodBuilders {
     private final ApiCallableBuilder<Subscription, Subscription> createSubscriptionMethod;
     private final ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionMethod;
@@ -198,8 +200,6 @@ public MethodBuilders() {
     }
   }
 
-  private final MethodBuilders methods;
-
   // ===============
   // Factory Methods
   // ===============
@@ -222,8 +222,9 @@ public static SubscriberSettings create() {
   }
 
   /**
-   * Constructs an instance of SubscriberSettings with default settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of SubscriberSettings with default settings. This is protected
+   * so that it easy to make a subclass, but otherwise, the static factory methods should be
+   * preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -234,7 +235,7 @@ protected SubscriberSettings(MethodBuilders methods) {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method createSubscription.
+   * Returns the builder for the API method createSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -244,7 +245,7 @@ public ApiCallableBuilder<Subscription, Subscription> createSubscriptionMethod()
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method getSubscription.
+   * Returns the builder for the API method getSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -254,7 +255,7 @@ public ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionM
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listSubscriptions.
+   * Returns the builder for the API method listSubscriptions.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -266,7 +267,7 @@ public ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionM
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method deleteSubscription.
+   * Returns the builder for the API method deleteSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -276,7 +277,7 @@ public ApiCallableBuilder<DeleteSubscriptionRequest, Empty> deleteSubscriptionMe
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method modifyAckDeadline.
+   * Returns the builder for the API method modifyAckDeadline.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -286,7 +287,7 @@ public ApiCallableBuilder<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineMeth
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method acknowledge.
+   * Returns the builder for the API method acknowledge.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -296,7 +297,7 @@ public ApiCallableBuilder<AcknowledgeRequest, Empty> acknowledgeMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method pull.
+   * Returns the builder for the API method pull.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -306,7 +307,7 @@ public ApiCallableBuilder<PullRequest, PullResponse> pullMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method modifyPushConfig.
+   * Returns the builder for the API method modifyPushConfig.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -315,9 +316,11 @@ public ApiCallableBuilder<ModifyPushConfigRequest, Empty> modifyPushConfigMethod
     return methods.modifyPushConfigMethod;
   }
 
-  private static PageDescriptor<ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>
+  private static PageStreamingDescriptor<
+          ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>
       LIST_SUBSCRIPTIONS_PAGE_STR_DESC =
-          new PageDescriptor<ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>() {
+          new PageStreamingDescriptor<
+              ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>() {
             @Override
             public Object emptyToken() {
               return "";
diff --git a/gcloud-java-pubsub/pom.xml b/gcloud-java-pubsub/pom.xml
index 2fccc5a6560c..2bd755f63a8c 100644
--- a/gcloud-java-pubsub/pom.xml
+++ b/gcloud-java-pubsub/pom.xml
@@ -19,7 +19,7 @@
     <dependency>
       <groupId>com.google.api</groupId>
       <artifactId>gax</artifactId>
-      <version>0.0.4</version>
+      <version>0.0.5</version>
     </dependency>
     <dependency>
       <groupId>com.google.api.grpc</groupId>
diff --git a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
index 6ace2998698b..fa6da27a72bd 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherApi.java
@@ -33,8 +33,9 @@
 
 package com.google.gcloud.pubsub.spi.v1;
 
-import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable;
+import com.google.api.gax.grpc.ApiCallable.BundlableApiCallableInfo;
+import com.google.api.gax.grpc.BundlerFactory;
 import com.google.api.gax.protobuf.PathTemplate;
 import com.google.protobuf.Empty;
 import com.google.pubsub.v1.DeleteTopicRequest;
@@ -65,9 +66,25 @@
  */
 @javax.annotation.Generated("by GAPIC")
 public class PublisherApi implements AutoCloseable {
+  // ========
+  // Members
+  // ========
+
+  private final ManagedChannel channel;
+  private final List<AutoCloseable> closeables = new ArrayList<>();
+
+  private final ApiCallable<Topic, Topic> createTopicCallable;
+  private final ApiCallable<PublishRequest, PublishResponse> publishCallable;
+  private final ApiCallable<GetTopicRequest, Topic> getTopicCallable;
+  private final ApiCallable<ListTopicsRequest, ListTopicsResponse> listTopicsCallable;
+  private final ApiCallable<ListTopicsRequest, Iterable<Topic>> listTopicsIterableCallable;
+  private final ApiCallable<ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse>
+      listTopicSubscriptionsCallable;
+  private final ApiCallable<ListTopicSubscriptionsRequest, Iterable<String>>
+      listTopicSubscriptionsIterableCallable;
+  private final ApiCallable<DeleteTopicRequest, Empty> deleteTopicCallable;
 
   public static class ResourceNames {
-    private ResourceNames() {}
 
     // =======================
     // ResourceNames Constants
@@ -93,6 +110,8 @@ private ResourceNames() {}
     private static final PathTemplate TOPIC_PATH_TEMPLATE =
         PathTemplate.create("projects/{project}/topics/{topic}");
 
+    private ResourceNames() {}
+
     // ==============================
     // Resource Name Helper Functions
     // ==============================
@@ -153,24 +172,6 @@ public static final String parseTopicFromTopicPath(String topicPath) {
     }
   }
 
-  // ========
-  // Members
-  // ========
-
-  private final ManagedChannel channel;
-  private final List<AutoCloseable> closeables = new ArrayList<>();
-
-  private final ApiCallable<Topic, Topic> createTopicCallable;
-  private final ApiCallable<PublishRequest, PublishResponse> publishCallable;
-  private final ApiCallable<GetTopicRequest, Topic> getTopicCallable;
-  private final ApiCallable<ListTopicsRequest, ListTopicsResponse> listTopicsCallable;
-  private final ApiCallable<ListTopicsRequest, Iterable<Topic>> listTopicsIterableCallable;
-  private final ApiCallable<ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse>
-      listTopicSubscriptionsCallable;
-  private final ApiCallable<ListTopicSubscriptionsRequest, Iterable<String>>
-      listTopicSubscriptionsIterableCallable;
-  private final ApiCallable<DeleteTopicRequest, Empty> deleteTopicCallable;
-
   // ===============
   // Factory Methods
   // ===============
@@ -186,8 +187,9 @@ public static PublisherApi create() throws IOException {
   }
 
   /**
-   * Constructs an instance of PublisherApi, using the given settings. The channels are created based
-   * on the settings passed in, or defaults for any settings that are not set.
+   * Constructs an instance of PublisherApi, using the given settings.
+   * The channels are created based on the settings passed in, or defaults for any
+   * settings that are not set.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -197,8 +199,9 @@ public static PublisherApi create(PublisherSettings settings) throws IOException
   }
 
   /**
-   * Constructs an instance of PublisherApi, using the given settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of PublisherApi, using the given settings.
+   * This is protected so that it easy to make a subclass, but otherwise, the static
+   * factory methods should be preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -207,7 +210,14 @@ protected PublisherApi(PublisherSettings settings) throws IOException {
     this.channel = settings.getChannel();
 
     this.createTopicCallable = settings.createTopicMethod().build(settings);
-    this.publishCallable = settings.publishMethod().build(settings);
+    BundlableApiCallableInfo<PublishRequest, PublishResponse> bundlablePublish =
+        settings.publishMethod().buildBundlable(settings);
+    this.publishCallable = bundlablePublish.getApiCallable();
+    BundlerFactory<PublishRequest, PublishResponse> publishBundlerFactory =
+        bundlablePublish.getBundlerFactory();
+    if (publishBundlerFactory != null) {
+      this.closeables.add(publishBundlerFactory);
+    }
     this.getTopicCallable = settings.getTopicMethod().build(settings);
     this.listTopicsCallable = settings.listTopicsMethod().build(settings);
     this.listTopicsIterableCallable = settings.listTopicsMethod().buildPageStreaming(settings);
diff --git a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
index 70b188735890..11566404546f 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/PublisherSettings.java
@@ -38,8 +38,11 @@
 import com.google.api.gax.core.RetryParams;
 import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable.ApiCallableBuilder;
+import com.google.api.gax.grpc.ApiCallable.BundlableApiCallableBuilder;
 import com.google.api.gax.grpc.ApiCallable.PageStreamingApiCallableBuilder;
-import com.google.api.gax.grpc.PageDescriptor;
+import com.google.api.gax.grpc.BundlingDescriptor;
+import com.google.api.gax.grpc.PageStreamingDescriptor;
+import com.google.api.gax.grpc.RequestIssuer;
 import com.google.api.gax.grpc.ServiceApiSettings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -56,8 +59,12 @@
 import com.google.pubsub.v1.PublishRequest;
 import com.google.pubsub.v1.PublishResponse;
 import com.google.pubsub.v1.PublisherGrpc;
+import com.google.pubsub.v1.PubsubMessage;
 import com.google.pubsub.v1.Topic;
 import io.grpc.Status;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 
 // Manually-added imports: add custom (non-generated) imports after this point.
 
@@ -132,9 +139,11 @@ public class PublisherSettings extends ServiceApiSettings {
     RETRY_PARAM_DEFINITIONS = definitions.build();
   }
 
+  private final MethodBuilders methods;
+
   private static class MethodBuilders {
     private final ApiCallableBuilder<Topic, Topic> createTopicMethod;
-    private final ApiCallableBuilder<PublishRequest, PublishResponse> publishMethod;
+    private final BundlableApiCallableBuilder<PublishRequest, PublishResponse> publishMethod;
     private final ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod;
     private final PageStreamingApiCallableBuilder<ListTopicsRequest, ListTopicsResponse, Topic>
         listTopicsMethod;
@@ -149,7 +158,8 @@ public MethodBuilders() {
       createTopicMethod.setRetryableCodes(RETRYABLE_CODE_DEFINITIONS.get("idempotent"));
       createTopicMethod.setRetryParams(RETRY_PARAM_DEFINITIONS.get("default"));
 
-      publishMethod = new ApiCallableBuilder<>(PublisherGrpc.METHOD_PUBLISH);
+      publishMethod =
+          new BundlableApiCallableBuilder<>(PublisherGrpc.METHOD_PUBLISH, PUBLISH_BUNDLING_DESC);
       publishMethod.setRetryableCodes(RETRYABLE_CODE_DEFINITIONS.get("non_idempotent"));
       publishMethod.setRetryParams(RETRY_PARAM_DEFINITIONS.get("default"));
 
@@ -187,8 +197,6 @@ public MethodBuilders() {
     }
   }
 
-  private final MethodBuilders methods;
-
   // ===============
   // Factory Methods
   // ===============
@@ -211,8 +219,9 @@ public static PublisherSettings create() {
   }
 
   /**
-   * Constructs an instance of PublisherSettings with default settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of PublisherSettings with default settings. This is protected
+   * so that it easy to make a subclass, but otherwise, the static factory methods should be
+   * preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -223,7 +232,7 @@ protected PublisherSettings(MethodBuilders methods) {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method createTopic.
+   * Returns the builder for the API method createTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -233,17 +242,17 @@ public ApiCallableBuilder<Topic, Topic> createTopicMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method publish.
+   * Returns the builder for the API method publish.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
    */
-  public ApiCallableBuilder<PublishRequest, PublishResponse> publishMethod() {
+  public BundlableApiCallableBuilder<PublishRequest, PublishResponse> publishMethod() {
     return methods.publishMethod;
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method getTopic.
+   * Returns the builder for the API method getTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -253,7 +262,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listTopics.
+   * Returns the builder for the API method listTopics.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -264,7 +273,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listTopicSubscriptions.
+   * Returns the builder for the API method listTopicSubscriptions.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -276,7 +285,7 @@ public ApiCallableBuilder<GetTopicRequest, Topic> getTopicMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method deleteTopic.
+   * Returns the builder for the API method deleteTopic.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -285,9 +294,9 @@ public ApiCallableBuilder<DeleteTopicRequest, Empty> deleteTopicMethod() {
     return methods.deleteTopicMethod;
   }
 
-  private static PageDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>
+  private static PageStreamingDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>
       LIST_TOPICS_PAGE_STR_DESC =
-          new PageDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>() {
+          new PageStreamingDescriptor<ListTopicsRequest, ListTopicsResponse, Topic>() {
             @Override
             public Object emptyToken() {
               return "";
@@ -309,10 +318,10 @@ public Iterable<Topic> extractResources(ListTopicsResponse payload) {
             }
           };
 
-  private static PageDescriptor<
+  private static PageStreamingDescriptor<
           ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse, String>
       LIST_TOPIC_SUBSCRIPTIONS_PAGE_STR_DESC =
-          new PageDescriptor<
+          new PageStreamingDescriptor<
               ListTopicSubscriptionsRequest, ListTopicSubscriptionsResponse, String>() {
             @Override
             public Object emptyToken() {
@@ -337,4 +346,66 @@ public Iterable<String> extractResources(ListTopicSubscriptionsResponse payload)
               return payload.getSubscriptionsList();
             }
           };
+
+  private static BundlingDescriptor<PublishRequest, PublishResponse> PUBLISH_BUNDLING_DESC =
+      new BundlingDescriptor<PublishRequest, PublishResponse>() {
+        @Override
+        public String getBundlePartitionKey(PublishRequest request) {
+          return request.getTopic();
+        }
+
+        @Override
+        public PublishRequest mergeRequests(Collection<PublishRequest> requests) {
+          PublishRequest firstRequest = requests.iterator().next();
+
+          List<PubsubMessage> elements = new ArrayList<>();
+          for (PublishRequest request : requests) {
+            elements.addAll(request.getMessagesList());
+          }
+
+          PublishRequest bundleRequest =
+              PublishRequest.newBuilder()
+                  .setTopic(firstRequest.getTopic())
+                  .addAllMessages(elements)
+                  .build();
+          return bundleRequest;
+        }
+
+        @Override
+        public void splitResponse(
+            PublishResponse bundleResponse,
+            Collection<? extends RequestIssuer<PublishRequest, PublishResponse>> bundle) {
+          int bundleMessageIndex = 0;
+          for (RequestIssuer<PublishRequest, PublishResponse> responder : bundle) {
+            List<String> subresponseElements = new ArrayList<>();
+            int subresponseCount = responder.getRequest().getMessagesCount();
+            for (int i = 0; i < subresponseCount; i++) {
+              subresponseElements.add(bundleResponse.getMessageIds(bundleMessageIndex));
+              bundleMessageIndex += 1;
+            }
+            PublishResponse response =
+                PublishResponse.newBuilder().addAllMessageIds(subresponseElements).build();
+            responder.setResponse(response);
+          }
+        }
+
+        @Override
+        public void splitException(
+            Throwable throwable,
+            Collection<? extends RequestIssuer<PublishRequest, PublishResponse>> bundle) {
+          for (RequestIssuer<PublishRequest, PublishResponse> responder : bundle) {
+            responder.setException(throwable);
+          }
+        }
+
+        @Override
+        public long countElements(PublishRequest request) {
+          return request.getMessagesCount();
+        }
+
+        @Override
+        public long countBytes(PublishRequest request) {
+          return request.getSerializedSize();
+        }
+      };
 }
diff --git a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
index 16e1435b8582..d53dca7f8885 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberApi.java
@@ -33,7 +33,6 @@
 
 package com.google.gcloud.pubsub.spi.v1;
 
-import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable;
 import com.google.api.gax.protobuf.PathTemplate;
 import com.google.protobuf.Empty;
@@ -66,9 +65,26 @@
  */
 @javax.annotation.Generated("by GAPIC")
 public class SubscriberApi implements AutoCloseable {
+  // ========
+  // Members
+  // ========
+
+  private final ManagedChannel channel;
+  private final List<AutoCloseable> closeables = new ArrayList<>();
+
+  private final ApiCallable<Subscription, Subscription> createSubscriptionCallable;
+  private final ApiCallable<GetSubscriptionRequest, Subscription> getSubscriptionCallable;
+  private final ApiCallable<ListSubscriptionsRequest, ListSubscriptionsResponse>
+      listSubscriptionsCallable;
+  private final ApiCallable<ListSubscriptionsRequest, Iterable<Subscription>>
+      listSubscriptionsIterableCallable;
+  private final ApiCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionCallable;
+  private final ApiCallable<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineCallable;
+  private final ApiCallable<AcknowledgeRequest, Empty> acknowledgeCallable;
+  private final ApiCallable<PullRequest, PullResponse> pullCallable;
+  private final ApiCallable<ModifyPushConfigRequest, Empty> modifyPushConfigCallable;
 
   public static class ResourceNames {
-    private ResourceNames() {}
 
     // =======================
     // ResourceNames Constants
@@ -94,6 +110,8 @@ private ResourceNames() {}
     private static final PathTemplate SUBSCRIPTION_PATH_TEMPLATE =
         PathTemplate.create("projects/{project}/subscriptions/{subscription}");
 
+    private ResourceNames() {}
+
     // ==============================
     // Resource Name Helper Functions
     // ==============================
@@ -155,25 +173,6 @@ public static final String parseSubscriptionFromSubscriptionPath(String subscrip
     }
   }
 
-  // ========
-  // Members
-  // ========
-
-  private final ManagedChannel channel;
-  private final List<AutoCloseable> closeables = new ArrayList<>();
-
-  private final ApiCallable<Subscription, Subscription> createSubscriptionCallable;
-  private final ApiCallable<GetSubscriptionRequest, Subscription> getSubscriptionCallable;
-  private final ApiCallable<ListSubscriptionsRequest, ListSubscriptionsResponse>
-      listSubscriptionsCallable;
-  private final ApiCallable<ListSubscriptionsRequest, Iterable<Subscription>>
-      listSubscriptionsIterableCallable;
-  private final ApiCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionCallable;
-  private final ApiCallable<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineCallable;
-  private final ApiCallable<AcknowledgeRequest, Empty> acknowledgeCallable;
-  private final ApiCallable<PullRequest, PullResponse> pullCallable;
-  private final ApiCallable<ModifyPushConfigRequest, Empty> modifyPushConfigCallable;
-
   // ===============
   // Factory Methods
   // ===============
@@ -189,8 +188,9 @@ public static SubscriberApi create() throws IOException {
   }
 
   /**
-   * Constructs an instance of SubscriberApi, using the given settings. The channels are created based
-   * on the settings passed in, or defaults for any settings that are not set.
+   * Constructs an instance of SubscriberApi, using the given settings.
+   * The channels are created based on the settings passed in, or defaults for any
+   * settings that are not set.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -200,8 +200,9 @@ public static SubscriberApi create(SubscriberSettings settings) throws IOExcepti
   }
 
   /**
-   * Constructs an instance of SubscriberApi, using the given settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of SubscriberApi, using the given settings.
+   * This is protected so that it easy to make a subclass, but otherwise, the static
+   * factory methods should be preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
diff --git a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
index 2680d8429938..d9da44aa81f7 100644
--- a/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
+++ b/gcloud-java-pubsub/src/main/java/com/google/gcloud/pubsub/spi/v1/SubscriberSettings.java
@@ -39,7 +39,7 @@
 import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiCallable.ApiCallableBuilder;
 import com.google.api.gax.grpc.ApiCallable.PageStreamingApiCallableBuilder;
-import com.google.api.gax.grpc.PageDescriptor;
+import com.google.api.gax.grpc.PageStreamingDescriptor;
 import com.google.api.gax.grpc.ServiceApiSettings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -133,6 +133,8 @@ public class SubscriberSettings extends ServiceApiSettings {
     RETRY_PARAM_DEFINITIONS = definitions.build();
   }
 
+  private final MethodBuilders methods;
+
   private static class MethodBuilders {
     private final ApiCallableBuilder<Subscription, Subscription> createSubscriptionMethod;
     private final ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionMethod;
@@ -198,8 +200,6 @@ public MethodBuilders() {
     }
   }
 
-  private final MethodBuilders methods;
-
   // ===============
   // Factory Methods
   // ===============
@@ -222,8 +222,9 @@ public static SubscriberSettings create() {
   }
 
   /**
-   * Constructs an instance of SubscriberSettings with default settings. This is protected so that it
-   * easy to make a subclass, but otherwise, the static factory methods should be preferred.
+   * Constructs an instance of SubscriberSettings with default settings. This is protected
+   * so that it easy to make a subclass, but otherwise, the static factory methods should be
+   * preferred.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -234,7 +235,7 @@ protected SubscriberSettings(MethodBuilders methods) {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method createSubscription.
+   * Returns the builder for the API method createSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -244,7 +245,7 @@ public ApiCallableBuilder<Subscription, Subscription> createSubscriptionMethod()
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method getSubscription.
+   * Returns the builder for the API method getSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -254,7 +255,7 @@ public ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionM
   }
 
   /**
-   * Returns the PageStreamingApiCallableBuilder for the API method listSubscriptions.
+   * Returns the builder for the API method listSubscriptions.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -266,7 +267,7 @@ public ApiCallableBuilder<GetSubscriptionRequest, Subscription> getSubscriptionM
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method deleteSubscription.
+   * Returns the builder for the API method deleteSubscription.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -276,7 +277,7 @@ public ApiCallableBuilder<DeleteSubscriptionRequest, Empty> deleteSubscriptionMe
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method modifyAckDeadline.
+   * Returns the builder for the API method modifyAckDeadline.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -286,7 +287,7 @@ public ApiCallableBuilder<ModifyAckDeadlineRequest, Empty> modifyAckDeadlineMeth
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method acknowledge.
+   * Returns the builder for the API method acknowledge.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -296,7 +297,7 @@ public ApiCallableBuilder<AcknowledgeRequest, Empty> acknowledgeMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method pull.
+   * Returns the builder for the API method pull.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -306,7 +307,7 @@ public ApiCallableBuilder<PullRequest, PullResponse> pullMethod() {
   }
 
   /**
-   * Returns the ApiCallableBuilder for the API method modifyPushConfig.
+   * Returns the builder for the API method modifyPushConfig.
    *
    * <!-- manual edit -->
    * <!-- end manual edit -->
@@ -315,9 +316,11 @@ public ApiCallableBuilder<ModifyPushConfigRequest, Empty> modifyPushConfigMethod
     return methods.modifyPushConfigMethod;
   }
 
-  private static PageDescriptor<ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>
+  private static PageStreamingDescriptor<
+          ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>
       LIST_SUBSCRIPTIONS_PAGE_STR_DESC =
-          new PageDescriptor<ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>() {
+          new PageStreamingDescriptor<
+              ListSubscriptionsRequest, ListSubscriptionsResponse, Subscription>() {
             @Override
             public Object emptyToken() {
               return "";
diff --git a/gcloud-java-pubsub/src/test/java/com/google/gcloud/pubsub/spi/v1/PublisherApiTest.java b/gcloud-java-pubsub/src/test/java/com/google/gcloud/pubsub/spi/v1/PublisherApiTest.java
index aaf292ff917d..c25ca51ee713 100644
--- a/gcloud-java-pubsub/src/test/java/com/google/gcloud/pubsub/spi/v1/PublisherApiTest.java
+++ b/gcloud-java-pubsub/src/test/java/com/google/gcloud/pubsub/spi/v1/PublisherApiTest.java
@@ -16,6 +16,7 @@
 
 import com.google.api.gax.core.BackoffParams;
 import com.google.api.gax.core.RetryParams;
+import com.google.api.gax.grpc.BundlingSettings;
 import com.google.gcloud.pubsub.testing.LocalPubsubHelper;
 import com.google.protobuf.ByteString;
 import com.google.pubsub.v1.PubsubMessage;
@@ -30,6 +31,7 @@
 import java.util.Collections;
 import java.util.List;
 
+import org.joda.time.Duration;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Assert;
@@ -40,6 +42,7 @@
 public class PublisherApiTest {
   private static LocalPubsubHelper pubsubHelper;
   private PublisherApi publisherApi;
+  private PublisherApi bundledPublisherApi;
   private SubscriberApi subscriberApi;
 
   @BeforeClass
@@ -79,6 +82,18 @@ public void setUp() throws Exception {
     publisherSettings.provideChannelWith(channel);
     publisherApi = PublisherApi.create(publisherSettings);
 
+    BundlingSettings bundlingSettings =
+        BundlingSettings.newBuilder()
+            .setElementCountThreshold(10)
+            .setDelayThreshold(Duration.standardSeconds(30))
+            .build();
+
+    PublisherSettings bundledPublisherSettings = PublisherSettings.create();
+    bundledPublisherSettings.setRetryParamsOnAllMethods(retryParams);
+    bundledPublisherSettings.provideChannelWith(channel);
+    bundledPublisherSettings.publishMethod().setBundlingSettings(bundlingSettings);
+    bundledPublisherApi = PublisherApi.create(bundledPublisherSettings);
+
     SubscriberSettings subscriberSettings = SubscriberSettings.create();
     subscriberSettings.setRetryParamsOnAllMethods(retryParams);
     subscriberSettings.provideChannelWith(channel);
@@ -93,6 +108,9 @@ public void tearDown() throws Exception {
     if (subscriberApi != null) {
       subscriberApi.close();
     }
+    if (bundledPublisherApi != null) {
+      bundledPublisherApi.close();
+    }
     pubsubHelper.reset();
   }
 
@@ -108,7 +126,8 @@ public void testPublish() throws Exception {
     String topicName = PublisherApi.ResourceNames.formatTopicPath("my-project", "publish-topic");
     publisherApi.createTopic(topicName);
 
-    String subscriberName = SubscriberApi.ResourceNames.formatSubscriptionPath("my-project", "my-subscribe");
+    String subscriberName =
+        SubscriberApi.ResourceNames.formatSubscriptionPath("my-project", "my-subscribe");
     PushConfig config = PushConfig.getDefaultInstance();
     subscriberApi.createSubscription(subscriberName, topicName, config, 5);
 
@@ -122,6 +141,27 @@ public void testPublish() throws Exception {
         "pubsub-message", response.getReceivedMessages(0).getMessage().getData().toStringUtf8());
   }
 
+  @Test
+  public void testBundledPublish() throws Exception {
+    String topicName = PublisherApi.ResourceNames.formatTopicPath("my-project", "publish-topic");
+    bundledPublisherApi.createTopic(topicName);
+
+    String subscriberName =
+        SubscriberApi.ResourceNames.formatSubscriptionPath("my-project", "my-subscribe");
+    PushConfig config = PushConfig.getDefaultInstance();
+    subscriberApi.createSubscription(subscriberName, topicName, config, 5);
+
+    PubsubMessage msg =
+        PubsubMessage.newBuilder().setData(ByteString.copyFromUtf8("pubsub-message")).build();
+    // This is a synchronous publish and should trigger the default blockingCallCountThreshold of 1
+    bundledPublisherApi.publish(topicName, Collections.singletonList(msg));
+
+    PullResponse response = subscriberApi.pull(subscriberName, true, 100);
+    Assert.assertEquals(1, response.getReceivedMessagesCount());
+    Assert.assertEquals(
+        "pubsub-message", response.getReceivedMessages(0).getMessage().getData().toStringUtf8());
+  }
+
   @Test
   public void testGetTopic() throws Exception {
     String topicName = PublisherApi.ResourceNames.formatTopicPath("my-project", "fun-topic");