diff --git a/.readme-partials.yaml b/.readme-partials.yaml
index 16de3f9b2..6fc6560b3 100644
--- a/.readme-partials.yaml
+++ b/.readme-partials.yaml
@@ -110,11 +110,11 @@ custom_content: |
       futures.add(future);
     }
   } finally {
-    ArrayList<PublishMetadata> metadata = new ArrayList<>();
+    ArrayList<MessageMetadata> metadata = new ArrayList<>();
     List<String> ackIds = ApiFutures.allAsList(futures).get();
     for (String id : ackIds) {
       // Decoded metadata contains partition and offset.
-      metadata.add(PublishMetadata.decode(id));
+      metadata.add(MessageMetadata.decode(id));
     }
     System.out.println(metadata + "\nPublished " + ackIds.size() + " messages.");
 
diff --git a/README.md b/README.md
index a89d793b0..0c00cefb2 100644
--- a/README.md
+++ b/README.md
@@ -188,11 +188,11 @@ try {
     futures.add(future);
   }
 } finally {
-  ArrayList<PublishMetadata> metadata = new ArrayList<>();
+  ArrayList<MessageMetadata> metadata = new ArrayList<>();
   List<String> ackIds = ApiFutures.allAsList(futures).get();
   for (String id : ackIds) {
     // Decoded metadata contains partition and offset.
-    metadata.add(PublishMetadata.decode(id));
+    metadata.add(MessageMetadata.decode(id));
   }
   System.out.println(metadata + "\nPublished " + ackIds.size() + " messages.");
 
diff --git a/google-cloud-pubsublite/clirr-ignored-differences.xml b/google-cloud-pubsublite/clirr-ignored-differences.xml
index f652e80d9..4bf5160bf 100644
--- a/google-cloud-pubsublite/clirr-ignored-differences.xml
+++ b/google-cloud-pubsublite/clirr-ignored-differences.xml
@@ -1,6 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- see http://www.mojohaus.org/clirr-maven-plugin/examples/ignored-differences.html -->
 <differences>
+  <!-- TODO: Remove on next release -->
+  <difference>
+    <differenceType>8001</differenceType>
+    <className>com/google/cloud/pubsublite/PublishMetadata</className>
+    <method>*</method>
+  </difference>
   <!-- Added abstract method to AutoValue.Builder class (Always okay) -->
   <difference>
     <differenceType>7013</differenceType>
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/PublishMetadata.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/MessageMetadata.java
similarity index 68%
rename from google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/PublishMetadata.java
rename to google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/MessageMetadata.java
index 155bec0a1..b7fdb87a8 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/PublishMetadata.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/MessageMetadata.java
@@ -24,32 +24,33 @@
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 
 /**
- * Information about a successful publish operation. Can be encoded in the string returned by the
- * Cloud Pub/Sub {@link com.google.cloud.pubsub.v1.Publisher#publish} api.
+ * Information about a message in Pub/Sub Lite. Can be encoded in the string returned by the Cloud
+ * Pub/Sub {@link com.google.cloud.pubsub.v1.Publisher#publish} api or the {@link
+ * com.google.pubsub.v1.PubsubMessage#getMessageId} field on received messages.
  */
 @AutoValue
-public abstract class PublishMetadata {
+public abstract class MessageMetadata {
   /** The partition a message was published to. */
   public abstract Partition partition();
 
   /** The offset a message was assigned. */
   public abstract Offset offset();
 
-  /** Construct a PublishMetadata from a Partition and Offset. */
-  public static PublishMetadata of(Partition partition, Offset offset) {
-    return new AutoValue_PublishMetadata(partition, offset);
+  /** Construct a MessageMetadata from a Partition and Offset. */
+  public static MessageMetadata of(Partition partition, Offset offset) {
+    return new AutoValue_MessageMetadata(partition, offset);
   }
 
-  /** Decode a PublishMetadata from the Cloud Pub/Sub ack id. */
-  public static PublishMetadata decode(String encoded) throws ApiException {
+  /** Decode a MessageMetadata from the Cloud Pub/Sub ack id. */
+  public static MessageMetadata decode(String encoded) throws ApiException {
     String[] split = encoded.split(":");
-    checkArgument(split.length == 2, "Invalid encoded PublishMetadata.");
+    checkArgument(split.length == 2, "Invalid encoded MessageMetadata.");
     try {
       Partition partition = Partition.of(Long.parseLong(split[0]));
       Offset offset = Offset.of(Long.parseLong(split[1]));
       return of(partition, offset);
     } catch (NumberFormatException e) {
-      throw new CheckedApiException("Invalid encoded PublishMetadata.", e, Code.INVALID_ARGUMENT)
+      throw new CheckedApiException("Invalid encoded MessageMetadata.", e, Code.INVALID_ARGUMENT)
           .underlying;
     }
   }
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransforms.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransforms.java
index a88095afd..bfb08bdc3 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransforms.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransforms.java
@@ -21,7 +21,9 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.api.gax.rpc.StatusCode.Code;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.MessageTransformer;
+import com.google.cloud.pubsublite.Partition;
 import com.google.cloud.pubsublite.SequencedMessage;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.common.collect.ImmutableListMultimap;
@@ -72,15 +74,30 @@ private static String parseAttributes(Collection<ByteString> values) throws ApiE
         "Received an unparseable message with multiple values for an attribute.");
     ByteString attribute = values.iterator().next();
     checkArgument(
-        attribute.isValidUtf8(), "Received an unparseable message with a non-utf8 attribute.");
+        attribute.isValidUtf8(),
+        String.format(
+            "Received an unparseable message with a non-utf8 attribute value: %s",
+            Base64.getEncoder().encodeToString(attribute.toByteArray())));
     return attribute.toStringUtf8();
   }
 
+  static MessageTransformer<SequencedMessage, PubsubMessage> addIdCpsSubscribeTransformer(
+      Partition partition, MessageTransformer<SequencedMessage, PubsubMessage> toWrap) {
+    return message -> {
+      PubsubMessage out = toWrap.transform(message);
+      checkArgument(
+          out.getMessageId().isEmpty(),
+          String.format("Received non-empty message id for PubsubMessage: %s", out));
+      return out.toBuilder()
+          .setMessageId(MessageMetadata.of(partition, message.offset()).encode())
+          .build();
+    };
+  }
+
   public static MessageTransformer<SequencedMessage, PubsubMessage> toCpsSubscribeTransformer() {
     return message -> {
       PubsubMessage.Builder outBuilder =
           toCpsPublishTransformer().transform(message.message()).toBuilder();
-      outBuilder.setMessageId(Long.toString(message.offset().value()));
       outBuilder.setPublishTime(message.publishTime());
       return outBuilder.build();
     };
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/SubscriberSettings.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/SubscriberSettings.java
index 7a22a3d20..923069ed1 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/SubscriberSettings.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/SubscriberSettings.java
@@ -88,7 +88,10 @@ public abstract class SubscriberSettings {
    */
   abstract List<Partition> partitions();
 
-  /** The MessageTransformer to get PubsubMessages from Pub/Sub Lite wire messages. */
+  /**
+   * The MessageTransformer to get PubsubMessages from Pub/Sub Lite wire messages. The messageId
+   * field must not be set on the returned message.
+   */
   abstract Optional<MessageTransformer<SequencedMessage, PubsubMessage>> transformer();
 
   /** A provider for credentials. */
@@ -155,7 +158,10 @@ public abstract static class Builder {
      */
     public abstract Builder setPartitions(List<Partition> partition);
 
-    /** The MessageTransformer to get PubsubMessages from Pub/Sub Lite wire messages. */
+    /**
+     * The MessageTransformer to get PubsubMessages from Pub/Sub Lite wire messages. The messageId
+     * field must not be set on the returned message.
+     */
     public abstract Builder setTransformer(
         MessageTransformer<SequencedMessage, PubsubMessage> transformer);
 
@@ -243,7 +249,8 @@ Subscriber newPartitionSubscriber(Partition partition) throws CheckedApiExceptio
 
       return new SinglePartitionSubscriber(
           receiver(),
-          transformer().orElse(MessageTransforms.toCpsSubscribeTransformer()),
+          MessageTransforms.addIdCpsSubscribeTransformer(
+              partition, transformer().orElse(MessageTransforms.toCpsSubscribeTransformer())),
           new AckSetTrackerImpl(wireCommitter),
           nackHandler().orElse(new NackHandler() {}),
           messageConsumer -> wireSubscriberBuilder.setMessageConsumer(messageConsumer).build(),
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisher.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisher.java
index 394b9d19b..7f99a6937 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisher.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisher.java
@@ -22,8 +22,8 @@
 import com.google.api.core.ApiFutures;
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.MessageTransformer;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.cloudpubsub.Publisher;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.cloud.pubsublite.internal.TrivialProxyService;
@@ -31,13 +31,13 @@
 import com.google.pubsub.v1.PubsubMessage;
 
 // A WrappingPublisher wraps the wire protocol client with a Cloud Pub/Sub api compliant
-// publisher. It encodes a PublishMetadata object in the response string.
+// publisher. It encodes a MessageMetadata object in the response string.
 public class WrappingPublisher extends TrivialProxyService implements Publisher {
-  private final com.google.cloud.pubsublite.internal.Publisher<PublishMetadata> wirePublisher;
+  private final com.google.cloud.pubsublite.internal.Publisher<MessageMetadata> wirePublisher;
   private final MessageTransformer<PubsubMessage, Message> transformer;
 
   public WrappingPublisher(
-      com.google.cloud.pubsublite.internal.Publisher<PublishMetadata> wirePublisher,
+      com.google.cloud.pubsublite.internal.Publisher<MessageMetadata> wirePublisher,
       MessageTransformer<PubsubMessage, Message> transformer)
       throws ApiException {
     super(wirePublisher);
@@ -58,7 +58,7 @@ public ApiFuture<String> publish(PubsubMessage message) {
     }
     return ApiFutures.transform(
         wirePublisher.publish(wireMessage),
-        PublishMetadata::encode,
+        MessageMetadata::encode,
         MoreExecutors.directExecutor());
   }
 }
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisher.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisher.java
index c4710de6d..b2a27e832 100644
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisher.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisher.java
@@ -23,8 +23,8 @@
 import com.google.api.core.ApiFutures;
 import com.google.api.core.ApiService;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.cloud.pubsublite.internal.CloseableMonitor;
 import com.google.cloud.pubsublite.internal.ProxyService;
@@ -39,23 +39,23 @@
 import java.util.stream.LongStream;
 
 public class PartitionCountWatchingPublisher extends ProxyService
-    implements Publisher<PublishMetadata> {
+    implements Publisher<MessageMetadata> {
   private static final GoogleLogger log = GoogleLogger.forEnclosingClass();
   private final PartitionPublisherFactory publisherFactory;
   private final RoutingPolicy.Factory policyFactory;
 
   private static class PartitionsWithRouting {
-    public final ImmutableMap<Partition, Publisher<PublishMetadata>> publishers;
+    public final ImmutableMap<Partition, Publisher<MessageMetadata>> publishers;
     private final RoutingPolicy routingPolicy;
 
     private PartitionsWithRouting(
-        ImmutableMap<Partition, Publisher<PublishMetadata>> publishers,
+        ImmutableMap<Partition, Publisher<MessageMetadata>> publishers,
         RoutingPolicy routingPolicy) {
       this.publishers = publishers;
       this.routingPolicy = routingPolicy;
     }
 
-    public ApiFuture<PublishMetadata> publish(Message message) throws CheckedApiException {
+    public ApiFuture<MessageMetadata> publish(Message message) throws CheckedApiException {
       try {
         Partition routedPartition =
             message.key().isEmpty()
@@ -73,13 +73,13 @@ public ApiFuture<PublishMetadata> publish(Message message) throws CheckedApiExce
     }
 
     public void cancelOutstandingPublishes() {
-      for (Publisher<PublishMetadata> publisher : publishers.values()) {
+      for (Publisher<MessageMetadata> publisher : publishers.values()) {
         publisher.cancelOutstandingPublishes();
       }
     }
 
     public void flush() throws IOException {
-      for (Publisher<PublishMetadata> publisher : publishers.values()) {
+      for (Publisher<MessageMetadata> publisher : publishers.values()) {
         publisher.flush();
       }
     }
@@ -109,7 +109,7 @@ public void stop() {
   }
 
   @Override
-  public ApiFuture<PublishMetadata> publish(Message message) {
+  public ApiFuture<MessageMetadata> publish(Message message) {
     Optional<PartitionsWithRouting> partitions;
     try (CloseableMonitor.Hold h = monitor.enter()) {
       partitions = partitionsWithRouting;
@@ -150,12 +150,12 @@ public void flush() throws IOException {
     partitions.get().flush();
   }
 
-  private ImmutableMap<Partition, Publisher<PublishMetadata>> getNewPartitionPublishers(
+  private ImmutableMap<Partition, Publisher<MessageMetadata>> getNewPartitionPublishers(
       LongStream newPartitions) {
-    ImmutableMap.Builder<Partition, Publisher<PublishMetadata>> mapBuilder = ImmutableMap.builder();
+    ImmutableMap.Builder<Partition, Publisher<MessageMetadata>> mapBuilder = ImmutableMap.builder();
     newPartitions.forEach(
         i -> {
-          Publisher<PublishMetadata> p = publisherFactory.newPublisher(Partition.of(i));
+          Publisher<MessageMetadata> p = publisherFactory.newPublisher(Partition.of(i));
           p.addListener(
               new Listener() {
                 @Override
@@ -167,7 +167,7 @@ public void failed(State from, Throwable failure) {
           mapBuilder.put(Partition.of(i), p);
           p.startAsync();
         });
-    ImmutableMap<Partition, Publisher<PublishMetadata>> partitions = mapBuilder.build();
+    ImmutableMap<Partition, Publisher<MessageMetadata>> partitions = mapBuilder.build();
     partitions.values().forEach(ApiService::awaitRunning);
     return partitions;
   }
@@ -189,12 +189,12 @@ private void handleConfig(long partitionCount) {
             partitionCount);
         return;
       }
-      ImmutableMap.Builder<Partition, Publisher<PublishMetadata>> mapBuilder =
+      ImmutableMap.Builder<Partition, Publisher<MessageMetadata>> mapBuilder =
           ImmutableMap.builder();
       current.ifPresent(p -> p.publishers.forEach(mapBuilder::put));
       getNewPartitionPublishers(LongStream.range(currentSize, partitionCount))
           .forEach(mapBuilder::put);
-      ImmutableMap<Partition, Publisher<PublishMetadata>> newMap = mapBuilder.build();
+      ImmutableMap<Partition, Publisher<MessageMetadata>> newMap = mapBuilder.build();
 
       partitionsWithRouting =
           Optional.of(
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherSettings.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherSettings.java
index 10f5d5808..8837faeb6 100644
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherSettings.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherSettings.java
@@ -54,7 +54,7 @@ public abstract static class Builder {
     public abstract PartitionCountWatchingPublisherSettings build();
   }
 
-  public Publisher<PublishMetadata> instantiate() throws ApiException {
+  public Publisher<MessageMetadata> instantiate() throws ApiException {
     return new PartitionCountWatchingPublisher(
         publisherFactory(),
         DefaultRoutingPolicy::new,
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionPublisherFactory.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionPublisherFactory.java
index 25caf08e9..ab3ff6beb 100644
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionPublisherFactory.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/PartitionPublisherFactory.java
@@ -17,10 +17,10 @@
 package com.google.cloud.pubsublite.internal.wire;
 
 import com.google.api.gax.rpc.ApiException;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.internal.Publisher;
 
 public interface PartitionPublisherFactory {
-  Publisher<PublishMetadata> newPublisher(Partition partition) throws ApiException;
+  Publisher<MessageMetadata> newPublisher(Partition partition) throws ApiException;
 }
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisher.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisher.java
index e1c62ffa1..ab912202b 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisher.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisher.java
@@ -23,8 +23,8 @@
 import com.google.api.core.ApiFutures;
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.cloud.pubsublite.internal.Publisher;
 import com.google.cloud.pubsublite.internal.RoutingPolicy;
@@ -32,12 +32,12 @@
 import java.io.IOException;
 import java.util.Map;
 
-public class RoutingPublisher extends TrivialProxyService implements Publisher<PublishMetadata> {
-  private final Map<Partition, Publisher<PublishMetadata>> partitionPublishers;
+public class RoutingPublisher extends TrivialProxyService implements Publisher<MessageMetadata> {
+  private final Map<Partition, Publisher<MessageMetadata>> partitionPublishers;
   private final RoutingPolicy policy;
 
   RoutingPublisher(
-      Map<Partition, Publisher<PublishMetadata>> partitionPublishers, RoutingPolicy policy)
+      Map<Partition, Publisher<MessageMetadata>> partitionPublishers, RoutingPolicy policy)
       throws ApiException {
     super(partitionPublishers.values());
     this.partitionPublishers = partitionPublishers;
@@ -46,7 +46,7 @@ public class RoutingPublisher extends TrivialProxyService implements Publisher<P
 
   // Publisher implementation.
   @Override
-  public ApiFuture<PublishMetadata> publish(Message message) {
+  public ApiFuture<MessageMetadata> publish(Message message) {
     try {
       Partition routedPartition =
           message.key().isEmpty() ? policy.routeWithoutKey() : policy.route(message.key());
@@ -65,14 +65,14 @@ public ApiFuture<PublishMetadata> publish(Message message) {
 
   @Override
   public void cancelOutstandingPublishes() {
-    for (Publisher<PublishMetadata> publisher : partitionPublishers.values()) {
+    for (Publisher<MessageMetadata> publisher : partitionPublishers.values()) {
       publisher.cancelOutstandingPublishes();
     }
   }
 
   @Override
   public void flush() throws IOException {
-    for (Publisher<PublishMetadata> publisher : partitionPublishers.values()) {
+    for (Publisher<MessageMetadata> publisher : partitionPublishers.values()) {
       publisher.flush();
     }
   }
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherBuilder.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherBuilder.java
index eb1b90af7..296c0ffc5 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherBuilder.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherBuilder.java
@@ -18,9 +18,9 @@
 
 import com.google.api.gax.rpc.ApiException;
 import com.google.auto.value.AutoValue;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Partition;
 import com.google.cloud.pubsublite.PartitionLookupUtils;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.internal.DefaultRoutingPolicy;
 import com.google.cloud.pubsublite.internal.Publisher;
@@ -53,7 +53,7 @@ public abstract static class Builder {
 
     abstract RoutingPublisherBuilder autoBuild();
 
-    public Publisher<PublishMetadata> build() throws ApiException {
+    public Publisher<MessageMetadata> build() throws ApiException {
       RoutingPublisherBuilder builder = autoBuild();
       int numPartitions;
       if (builder.numPartitions().isPresent()) {
@@ -62,7 +62,7 @@ public Publisher<PublishMetadata> build() throws ApiException {
         numPartitions = PartitionLookupUtils.numPartitions(builder.topic());
       }
 
-      ImmutableMap.Builder<Partition, Publisher<PublishMetadata>> publisherMapBuilder =
+      ImmutableMap.Builder<Partition, Publisher<MessageMetadata>> publisherMapBuilder =
           ImmutableMap.builder();
       for (int i = 0; i < numPartitions; i++) {
         publisherMapBuilder.put(
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisher.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisher.java
index 510724b85..b4a662e8a 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisher.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisher.java
@@ -20,16 +20,16 @@
 import com.google.api.core.ApiFutures;
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Offset;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.internal.Publisher;
 import com.google.cloud.pubsublite.internal.TrivialProxyService;
 import com.google.common.util.concurrent.MoreExecutors;
 import java.io.IOException;
 
 public class SinglePartitionPublisher extends TrivialProxyService
-    implements Publisher<PublishMetadata> {
+    implements Publisher<MessageMetadata> {
   private final Publisher<Offset> publisher;
   private final Partition partition;
 
@@ -41,10 +41,10 @@ public class SinglePartitionPublisher extends TrivialProxyService
 
   // Publisher implementation.
   @Override
-  public ApiFuture<PublishMetadata> publish(Message message) {
+  public ApiFuture<MessageMetadata> publish(Message message) {
     return ApiFutures.transform(
         publisher.publish(message),
-        offset -> PublishMetadata.of(partition, offset),
+        offset -> MessageMetadata.of(partition, offset),
         MoreExecutors.directExecutor());
   }
 
diff --git a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherBuilder.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherBuilder.java
index 35a5706b3..9faf22b06 100755
--- a/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherBuilder.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherBuilder.java
@@ -19,8 +19,8 @@
 import com.google.api.gax.batching.BatchingSettings;
 import com.google.api.gax.rpc.ApiException;
 import com.google.auto.value.AutoValue;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.internal.Publisher;
 import com.google.cloud.pubsublite.v1.PublisherServiceClient;
@@ -63,7 +63,7 @@ public abstract static class Builder {
 
     abstract SinglePartitionPublisherBuilder autoBuild();
 
-    public Publisher<PublishMetadata> build() throws ApiException {
+    public Publisher<MessageMetadata> build() throws ApiException {
       SinglePartitionPublisherBuilder builder = autoBuild();
       PublisherBuilder.Builder publisherBuilder =
           builder
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/PublishMetadataTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/MessageMetadataTest.java
similarity index 76%
rename from google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/PublishMetadataTest.java
rename to google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/MessageMetadataTest.java
index bb46259ea..c56fab8b4 100755
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/PublishMetadataTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/MessageMetadataTest.java
@@ -25,26 +25,26 @@
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
-public final class PublishMetadataTest {
+public final class MessageMetadataTest {
   @Test
   public void roundTripThroughString() {
-    PublishMetadata metadata = PublishMetadata.of(Partition.of(10), Offset.of(20));
-    PublishMetadata metadata2 = PublishMetadata.decode(metadata.encode());
+    MessageMetadata metadata = MessageMetadata.of(Partition.of(10), Offset.of(20));
+    MessageMetadata metadata2 = MessageMetadata.decode(metadata.encode());
     assertThat(metadata2).isEqualTo(metadata);
   }
 
   @Test
   public void invalidString() {
-    assertThrows(ApiException.class, () -> PublishMetadata.decode("999"));
+    assertThrows(ApiException.class, () -> MessageMetadata.decode("999"));
   }
 
   @Test
   public void invalidPartition() {
-    assertThrows(ApiException.class, () -> PublishMetadata.decode("abc:999"));
+    assertThrows(ApiException.class, () -> MessageMetadata.decode("abc:999"));
   }
 
   @Test
   public void invalidOffset() {
-    assertThrows(ApiException.class, () -> PublishMetadata.decode("999:abc"));
+    assertThrows(ApiException.class, () -> MessageMetadata.decode("999:abc"));
   }
 }
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransformsTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransformsTest.java
index a8e0d628b..2595c77c4 100755
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransformsTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/MessageTransformsTest.java
@@ -16,14 +16,20 @@
 
 package com.google.cloud.pubsublite.cloudpubsub;
 
+import static com.google.cloud.pubsublite.internal.testing.UnitTestExamples.example;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 import com.google.api.gax.rpc.ApiException;
 import com.google.api.gax.rpc.StatusCode.Code;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.MessageTransformer;
 import com.google.cloud.pubsublite.Offset;
+import com.google.cloud.pubsublite.Partition;
 import com.google.cloud.pubsublite.SequencedMessage;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.common.collect.ImmutableListMultimap;
@@ -141,7 +147,6 @@ public void subscribeTransformCorrect() throws ApiException {
     PubsubMessage result =
         PubsubMessage.newBuilder()
             .setData(message.message().data())
-            .setMessageId("7") // The offset as a string
             .setOrderingKey("some_key") // The key field
             .setPublishTime(message.publishTime())
             .putAttributes("abc", "")
@@ -153,6 +158,72 @@ public void subscribeTransformCorrect() throws ApiException {
     assertThat(subscribeTransformer.transform(message)).isEqualTo(result);
   }
 
+  @Test
+  public void wrappedSubscribeTransformerSetsIdFailure() throws ApiException {
+    MessageTransformer<SequencedMessage, PubsubMessage> mockTransformer =
+        mock(MessageTransformer.class);
+    MessageTransformer<SequencedMessage, PubsubMessage> wrapped =
+        MessageTransforms.addIdCpsSubscribeTransformer(example(Partition.class), mockTransformer);
+    when(mockTransformer.transform(any()))
+        .thenReturn(PubsubMessage.newBuilder().setMessageId("3").build());
+    ApiException e =
+        assertThrows(
+            ApiException.class,
+            () ->
+                wrapped.transform(
+                    SequencedMessage.of(
+                        Message.builder()
+                            .setAttributes(
+                                ImmutableListMultimap.<String, ByteString>builder()
+                                    .put("abc", ByteString.EMPTY)
+                                    .put("def", ByteString.copyFromUtf8("hij"))
+                                    .build())
+                            .setData(ByteString.copyFrom(notUtf8Array))
+                            .setEventTime(Timestamps.fromNanos(10))
+                            .setKey(ByteString.copyFromUtf8("some_key"))
+                            .build(),
+                        Timestamps.fromSeconds(5),
+                        Offset.of(7),
+                        2)));
+    assertThat(e.getStatusCode().getCode()).isEqualTo(Code.INVALID_ARGUMENT);
+  }
+
+  @Test
+  public void wrappedSubscribeTransformerMetadataId() throws ApiException {
+    MessageTransformer<SequencedMessage, PubsubMessage> wrapped =
+        MessageTransforms.addIdCpsSubscribeTransformer(
+            example(Partition.class), subscribeTransformer);
+    SequencedMessage message =
+        SequencedMessage.of(
+            Message.builder()
+                .setAttributes(
+                    ImmutableListMultimap.<String, ByteString>builder()
+                        .put("abc", ByteString.EMPTY)
+                        .put("def", ByteString.copyFromUtf8("hij"))
+                        .build())
+                .setData(ByteString.copyFrom(notUtf8Array))
+                .setEventTime(Timestamps.fromNanos(10))
+                .setKey(ByteString.copyFromUtf8("some_key"))
+                .build(),
+            Timestamps.fromSeconds(5),
+            example(Offset.class),
+            2);
+    PubsubMessage result =
+        PubsubMessage.newBuilder()
+            .setData(message.message().data())
+            .setMessageId(
+                MessageMetadata.of(example(Partition.class), example(Offset.class)).encode())
+            .setOrderingKey("some_key") // The key field
+            .setPublishTime(message.publishTime())
+            .putAttributes("abc", "")
+            .putAttributes("def", "hij")
+            .putAttributes(
+                MessageTransforms.PUBSUB_LITE_EVENT_TIME_TIMESTAMP_PROTO,
+                MessageTransforms.encodeAttributeEventTime(message.message().eventTime().get()))
+            .build();
+    assertThat(wrapped.transform(message)).isEqualTo(result);
+  }
+
   @Test
   public void publishTransformExtractorFailure() {
     MessageTransformer<PubsubMessage, Message> transformer =
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/PublisherSettingsTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/PublisherSettingsTest.java
index acdc76d36..09031b991 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/PublisherSettingsTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/PublisherSettingsTest.java
@@ -23,8 +23,8 @@
 
 import com.google.cloud.pubsublite.AdminClient;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
@@ -49,7 +49,7 @@ TopicPath getPath() throws CheckedApiException {
   }
 
   abstract static class FakePublisher extends FakeApiService
-      implements Publisher<PublishMetadata> {}
+      implements Publisher<MessageMetadata> {}
 
   abstract static class FakeConfigWatcher extends FakeApiService implements PartitionCountWatcher {}
 
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisherTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisherTest.java
index ff9c0e1d6..6bc4d7b57 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisherTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/WrappingPublisherTest.java
@@ -27,9 +27,9 @@
 import com.google.api.core.SettableApiFuture;
 import com.google.api.gax.rpc.StatusCode.Code;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Offset;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.cloudpubsub.KeyExtractor;
 import com.google.cloud.pubsublite.cloudpubsub.MessageTransforms;
 import com.google.cloud.pubsublite.internal.ApiExceptionMatcher;
@@ -48,7 +48,7 @@
 @RunWith(JUnit4.class)
 public class WrappingPublisherTest {
   abstract static class FakePublisher extends FakeApiService
-      implements Publisher<PublishMetadata> {}
+      implements Publisher<MessageMetadata> {}
 
   @Spy private FakePublisher underlying;
 
@@ -76,12 +76,12 @@ public void tearDown() {
   public void validPublish() throws Exception {
     PubsubMessage message = PubsubMessage.newBuilder().setOrderingKey("abc").build();
     Message wireMessage = Message.builder().setKey(ByteString.copyFromUtf8("abc")).build();
-    SettableApiFuture<PublishMetadata> metadataFuture = SettableApiFuture.create();
+    SettableApiFuture<MessageMetadata> metadataFuture = SettableApiFuture.create();
     when(underlying.publish(wireMessage)).thenReturn(metadataFuture);
     ApiFuture<String> published = publisher.publish(message);
     verify(underlying).publish(wireMessage);
     assertThat(published.isDone()).isFalse();
-    PublishMetadata metadata = PublishMetadata.of(Partition.of(3), Offset.of(88));
+    MessageMetadata metadata = MessageMetadata.of(Partition.of(3), Offset.of(88));
     metadataFuture.set(metadata);
     assertThat(published.isDone()).isTrue();
     assertThat(published.get()).isEqualTo(metadata.encode());
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherTest.java
index 3ecd5ac28..a49aae5d0 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/PartitionCountWatchingPublisherTest.java
@@ -40,7 +40,7 @@
 @RunWith(JUnit4.class)
 public class PartitionCountWatchingPublisherTest {
   abstract static class FakePublisher extends FakeApiService
-      implements Publisher<PublishMetadata> {}
+      implements Publisher<MessageMetadata> {}
 
   abstract static class FakeConfigWatcher extends FakeApiService implements PartitionCountWatcher {}
 
@@ -62,18 +62,18 @@ private static TopicPath path() {
   Consumer<Long> leakedConsumer;
   @Spy FakeConfigWatcher fakeConfigWatcher;
 
-  Publisher<PublishMetadata> publisher;
+  Publisher<MessageMetadata> publisher;
 
   @Before
   public void setUp() {
     initMocks(this);
-    doReturn(ApiFutures.immediateFuture(PublishMetadata.of(Partition.of(0), Offset.of(0))))
+    doReturn(ApiFutures.immediateFuture(MessageMetadata.of(Partition.of(0), Offset.of(0))))
         .when(publisher0)
         .publish(any());
-    doReturn(ApiFutures.immediateFuture(PublishMetadata.of(Partition.of(1), Offset.of(0))))
+    doReturn(ApiFutures.immediateFuture(MessageMetadata.of(Partition.of(1), Offset.of(0))))
         .when(publisher1)
         .publish(any());
-    doReturn(ApiFutures.immediateFuture(PublishMetadata.of(Partition.of(2), Offset.of(0))))
+    doReturn(ApiFutures.immediateFuture(MessageMetadata.of(Partition.of(2), Offset.of(0))))
         .when(publisher2)
         .publish(any());
     when(mockPublisherFactory.newPublisher(Partition.of(0))).thenReturn(publisher0);
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherTest.java
index b5775148d..b14bc51c8 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/RoutingPublisherTest.java
@@ -26,9 +26,9 @@
 import com.google.api.core.ApiFutures;
 import com.google.api.gax.rpc.StatusCode.Code;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Offset;
 import com.google.cloud.pubsublite.Partition;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.internal.ApiExceptionMatcher;
 import com.google.cloud.pubsublite.internal.CheckedApiException;
 import com.google.cloud.pubsublite.internal.Publisher;
@@ -46,7 +46,7 @@
 @RunWith(JUnit4.class)
 public class RoutingPublisherTest {
   abstract static class FakePublisher extends FakeApiService
-      implements Publisher<PublishMetadata> {}
+      implements Publisher<MessageMetadata> {}
 
   @Spy private FakePublisher publisher0;
   @Spy private FakePublisher publisher1;
@@ -84,9 +84,9 @@ public void cancelOutstandingCancelsAll() throws Exception {
   public void publishValidRoute() throws Exception {
     Message message = Message.builder().setKey(ByteString.copyFromUtf8("abc")).build();
     when(routingPolicy.route(message.key())).thenReturn(Partition.of(1));
-    PublishMetadata meta = PublishMetadata.of(Partition.of(1), Offset.of(3));
+    MessageMetadata meta = MessageMetadata.of(Partition.of(1), Offset.of(3));
     when(publisher1.publish(message)).thenReturn(ApiFutures.immediateFuture(meta));
-    ApiFuture<PublishMetadata> fut = routing.publish(message);
+    ApiFuture<MessageMetadata> fut = routing.publish(message);
     verify(publisher1, times(1)).publish(message);
     assertThat(fut.get()).isEqualTo(meta);
     this.routing.stopAsync().awaitTerminated();
@@ -96,7 +96,7 @@ public void publishValidRoute() throws Exception {
   public void publishInvalidRoute() throws Exception {
     Message message = Message.builder().setKey(ByteString.copyFromUtf8("abc")).build();
     when(routingPolicy.route(message.key())).thenReturn(Partition.of(77));
-    ApiFuture<PublishMetadata> fut = routing.publish(message);
+    ApiFuture<MessageMetadata> fut = routing.publish(message);
     ApiExceptionMatcher.assertFutureThrowsCode(fut, Code.FAILED_PRECONDITION);
   }
 }
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherTest.java
index 7229e55ff..ad81ec7c5 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/internal/wire/SinglePartitionPublisherTest.java
@@ -30,10 +30,10 @@
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
 import com.google.cloud.pubsublite.Message;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.Offset;
 import com.google.cloud.pubsublite.Partition;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.internal.Publisher;
@@ -52,7 +52,7 @@ abstract static class FakeOffsetPublisher extends FakeApiService implements Publ
 
   @Spy private FakeOffsetPublisher underlying;
 
-  private Publisher<PublishMetadata> pub;
+  private Publisher<MessageMetadata> pub;
 
   @Before
   public void setUp() {
@@ -86,11 +86,11 @@ public void publishResultTransformed() throws Exception {
     SettableApiFuture<Offset> offsetFuture = SettableApiFuture.create();
     Message message = Message.builder().setData(ByteString.copyFromUtf8("xyz")).build();
     when(underlying.publish(message)).thenReturn(offsetFuture);
-    ApiFuture<PublishMetadata> metadataFuture = pub.publish(message);
+    ApiFuture<MessageMetadata> metadataFuture = pub.publish(message);
     assertThat(metadataFuture.isDone()).isFalse();
     offsetFuture.set(Offset.of(7));
     assertThat(metadataFuture.isDone()).isTrue();
-    assertThat(metadataFuture.get()).isEqualTo(PublishMetadata.of(Partition.of(3), Offset.of(7)));
+    assertThat(metadataFuture.get()).isEqualTo(MessageMetadata.of(Partition.of(3), Offset.of(7)));
     pub.stopAsync().awaitTerminated();
   }
 
diff --git a/samples/snippets/src/main/java/pubsublite/PublishWithBatchSettingsExample.java b/samples/snippets/src/main/java/pubsublite/PublishWithBatchSettingsExample.java
index b8402f372..a1ea03002 100644
--- a/samples/snippets/src/main/java/pubsublite/PublishWithBatchSettingsExample.java
+++ b/samples/snippets/src/main/java/pubsublite/PublishWithBatchSettingsExample.java
@@ -23,8 +23,8 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.cloudpubsub.Publisher;
@@ -101,7 +101,7 @@ public static void publishWithBatchSettingsExample(
         futures.add(future);
       }
     } finally {
-      ArrayList<PublishMetadata> metadata = new ArrayList<>();
+      ArrayList<MessageMetadata> metadata = new ArrayList<>();
       List<String> ackIds = ApiFutures.allAsList(futures).get();
       System.out.println("Published " + ackIds.size() + " messages with batch settings.");
 
diff --git a/samples/snippets/src/main/java/pubsublite/PublishWithCustomAttributesExample.java b/samples/snippets/src/main/java/pubsublite/PublishWithCustomAttributesExample.java
index 168bdab16..f633aa15e 100644
--- a/samples/snippets/src/main/java/pubsublite/PublishWithCustomAttributesExample.java
+++ b/samples/snippets/src/main/java/pubsublite/PublishWithCustomAttributesExample.java
@@ -21,8 +21,8 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.cloudpubsub.Publisher;
@@ -82,7 +82,7 @@ public static void publishWithCustomAttributesExample(
     publisher.stopAsync().awaitTerminated();
 
     String ackId = future.get();
-    PublishMetadata metadata = PublishMetadata.decode(ackId);
+    MessageMetadata metadata = MessageMetadata.decode(ackId);
     System.out.println("Published a message with custom attributes:\n" + metadata);
   }
 }
diff --git a/samples/snippets/src/main/java/pubsublite/PublishWithOrderingKeyExample.java b/samples/snippets/src/main/java/pubsublite/PublishWithOrderingKeyExample.java
index c08eb1234..87881ec82 100644
--- a/samples/snippets/src/main/java/pubsublite/PublishWithOrderingKeyExample.java
+++ b/samples/snippets/src/main/java/pubsublite/PublishWithOrderingKeyExample.java
@@ -21,8 +21,8 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.cloudpubsub.Publisher;
@@ -83,7 +83,7 @@ public static void publishWithOrderingKeyExample(
     publisher.stopAsync().awaitTerminated();
 
     String ackId = future.get();
-    PublishMetadata metadata = PublishMetadata.decode(ackId);
+    MessageMetadata metadata = MessageMetadata.decode(ackId);
     System.out.println("Published a message with ordering key:\n" + metadata);
   }
 }
diff --git a/samples/snippets/src/main/java/pubsublite/PublisherExample.java b/samples/snippets/src/main/java/pubsublite/PublisherExample.java
index e6f534d36..e7312923b 100644
--- a/samples/snippets/src/main/java/pubsublite/PublisherExample.java
+++ b/samples/snippets/src/main/java/pubsublite/PublisherExample.java
@@ -22,8 +22,8 @@
 import com.google.api.gax.rpc.ApiException;
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
-import com.google.cloud.pubsublite.PublishMetadata;
 import com.google.cloud.pubsublite.TopicName;
 import com.google.cloud.pubsublite.TopicPath;
 import com.google.cloud.pubsublite.cloudpubsub.Publisher;
@@ -83,11 +83,11 @@ public static void publisherExample(
         futures.add(future);
       }
     } finally {
-      ArrayList<PublishMetadata> metadata = new ArrayList<>();
+      ArrayList<MessageMetadata> metadata = new ArrayList<>();
       List<String> ackIds = ApiFutures.allAsList(futures).get();
       for (String id : ackIds) {
         // Decoded metadata contains partition and offset.
-        metadata.add(PublishMetadata.decode(id));
+        metadata.add(MessageMetadata.decode(id));
       }
       System.out.println(metadata + "\nPublished " + ackIds.size() + " messages.");
 
diff --git a/samples/snippets/src/main/java/pubsublite/SubscriberExample.java b/samples/snippets/src/main/java/pubsublite/SubscriberExample.java
index fb7064beb..a6e0c76f1 100644
--- a/samples/snippets/src/main/java/pubsublite/SubscriberExample.java
+++ b/samples/snippets/src/main/java/pubsublite/SubscriberExample.java
@@ -22,6 +22,7 @@
 import com.google.cloud.pubsub.v1.MessageReceiver;
 import com.google.cloud.pubsublite.CloudRegion;
 import com.google.cloud.pubsublite.CloudZone;
+import com.google.cloud.pubsublite.MessageMetadata;
 import com.google.cloud.pubsublite.ProjectNumber;
 import com.google.cloud.pubsublite.SubscriptionName;
 import com.google.cloud.pubsublite.SubscriptionPath;
@@ -68,7 +69,7 @@ public static void subscriberExample(
 
     MessageReceiver receiver =
         (PubsubMessage message, AckReplyConsumer consumer) -> {
-          System.out.println("Id : " + message.getMessageId());
+          System.out.println("Id : " + MessageMetadata.decode(message.getMessageId()));
           System.out.println("Data : " + message.getData().toStringUtf8());
           consumer.ack();
         };