diff --git a/lib/api/model/events.dart b/lib/api/model/events.dart
index 985f5b5803..df15295894 100644
--- a/lib/api/model/events.dart
+++ b/lib/api/model/events.dart
@@ -665,8 +665,7 @@ class UserTopicEvent extends Event {
 }
 
 /// A Zulip event of type `message`: https://zulip.com/api/get-events#message
-// TODO use [JsonSerializable] here too, using its customization features,
-//   in order to skip the boilerplate in [fromJson] and [toJson].
+@JsonSerializable(fieldRename: FieldRename.snake)
 class MessageEvent extends Event {
   @override
   @JsonKey(includeToJson: true)
@@ -680,24 +679,30 @@ class MessageEvent extends Event {
   // events and in the get-messages results is that `matchContent` and
   // `matchTopic` are absent here.  Already [Message.matchContent] and
   // [Message.matchTopic] are optional, so no action is needed on that.
+  @JsonKey(readValue: _readMessageValue, includeToJson: false)
   final Message message;
 
-  MessageEvent({required super.id, required this.message});
+  // When present, this equals the "local_id" parameter
+  // from a previous [sendMessage] call by us.
+  //
+  // This is not yet fully documented.  See CZO discussion for reference:
+  //   https://chat.zulip.org/#narrow/channel/412-api-documentation/topic/local_id.2C.20queue_id.2Fsender_queue_id/near/2135340
+  final String? localMessageId;
+
+  MessageEvent({required super.id, required this.message, required this.localMessageId});
+
+  static Map<String, dynamic> _readMessageValue(Map<dynamic, dynamic> json, String key) =>
+    {...json['message'] as Map<String, dynamic>, 'flags': json['flags']};
 
-  factory MessageEvent.fromJson(Map<String, dynamic> json) => MessageEvent(
-    id: json['id'] as int,
-    message: Message.fromJson({
-      ...json['message'] as Map<String, dynamic>,
-      'flags': (json['flags'] as List<dynamic>).map((e) => e as String).toList(),
-    }),
-  );
+  factory MessageEvent.fromJson(Map<String, dynamic> json) =>
+    _$MessageEventFromJson(json);
 
   @override
   Map<String, dynamic> toJson() {
     final messageJson = message.toJson();
     final flags = messageJson['flags'];
     messageJson.remove('flags');
-    return {'id': id, 'type': type, 'message': messageJson, 'flags': flags};
+    return {..._$MessageEventToJson(this), 'message': messageJson, 'flags': flags};
   }
 }
 
diff --git a/lib/api/model/events.g.dart b/lib/api/model/events.g.dart
index c5b56d013a..35206d77b9 100644
--- a/lib/api/model/events.g.dart
+++ b/lib/api/model/events.g.dart
@@ -428,6 +428,21 @@ const _$UserTopicVisibilityPolicyEnumMap = {
   UserTopicVisibilityPolicy.unknown: null,
 };
 
+MessageEvent _$MessageEventFromJson(Map<String, dynamic> json) => MessageEvent(
+  id: (json['id'] as num).toInt(),
+  message: Message.fromJson(
+    MessageEvent._readMessageValue(json, 'message') as Map<String, dynamic>,
+  ),
+  localMessageId: json['local_message_id'] as String?,
+);
+
+Map<String, dynamic> _$MessageEventToJson(MessageEvent instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'type': instance.type,
+      'local_message_id': instance.localMessageId,
+    };
+
 UpdateMessageEvent _$UpdateMessageEventFromJson(Map<String, dynamic> json) =>
     UpdateMessageEvent(
       id: (json['id'] as num).toInt(),
diff --git a/lib/api/route/messages.dart b/lib/api/route/messages.dart
index 5af312ce45..dcd7998ee8 100644
--- a/lib/api/route/messages.dart
+++ b/lib/api/route/messages.dart
@@ -193,8 +193,8 @@ Future<SendMessageResult> sendMessage(
         'to': destination.userIds,
       }}),
     'content': RawParameter(content),
-    if (queueId != null) 'queue_id': queueId, // TODO should this use RawParameter?
-    if (localId != null) 'local_id': localId, // TODO should this use RawParameter?
+    if (queueId != null) 'queue_id': RawParameter(queueId),
+    if (localId != null) 'local_id': RawParameter(localId),
     if (readBySender != null) 'read_by_sender': readBySender,
   },
   overrideUserAgent: switch ((supportsReadBySender, readBySender)) {
diff --git a/test/api/model/events_checks.dart b/test/api/model/events_checks.dart
index 12d74479de..59d01d67ac 100644
--- a/test/api/model/events_checks.dart
+++ b/test/api/model/events_checks.dart
@@ -39,6 +39,7 @@ extension SubscriptionUpdateEventChecks on Subject<SubscriptionUpdateEvent> {
 
 extension MessageEventChecks on Subject<MessageEvent> {
   Subject<Message> get message => has((e) => e.message, 'message');
+  Subject<String?> get localMessageId => has((e) => e.localMessageId, 'localMessageId');
 }
 
 extension UpdateMessageEventChecks on Subject<UpdateMessageEvent> {
diff --git a/test/api/route/messages_test.dart b/test/api/route/messages_test.dart
index a29a87e24b..416fca4f3b 100644
--- a/test/api/route/messages_test.dart
+++ b/test/api/route/messages_test.dart
@@ -362,8 +362,8 @@ void main() {
             'to': streamId.toString(),
             'topic': topic,
             'content': content,
-            'queue_id': '"abc:123"',
-            'local_id': '"456"',
+            'queue_id': 'abc:123',
+            'local_id': '456',
             'read_by_sender': 'true',
           });
       });
diff --git a/test/example_data.dart b/test/example_data.dart
index af1be189d4..afa378aa7e 100644
--- a/test/example_data.dart
+++ b/test/example_data.dart
@@ -622,6 +622,9 @@ UserTopicEvent userTopicEvent(
   );
 }
 
+MessageEvent messageEvent(Message message) =>
+  MessageEvent(id: 0, message: message, localMessageId: null);
+
 DeleteMessageEvent deleteMessageEvent(List<StreamMessage> messages) {
   assert(messages.isNotEmpty);
   final streamId = messages.first.streamId;
diff --git a/test/model/message_list_test.dart b/test/model/message_list_test.dart
index 92c08ddd6b..6f00d83dc6 100644
--- a/test/model/message_list_test.dart
+++ b/test/model/message_list_test.dart
@@ -367,8 +367,7 @@ void main() {
       List.generate(30, (i) => eg.streamMessage(stream: stream)));
 
     check(model).messages.length.equals(30);
-    await store.handleEvent(MessageEvent(id: 0,
-      message: eg.streamMessage(stream: stream)));
+    await store.addMessage(eg.streamMessage(stream: stream));
     checkNotifiedOnce();
     check(model).messages.length.equals(31);
   });
@@ -381,8 +380,7 @@ void main() {
 
     check(model).messages.length.equals(30);
     final otherStream = eg.stream();
-    await store.handleEvent(MessageEvent(id: 0,
-      message: eg.streamMessage(stream: otherStream)));
+    await store.addMessage(eg.streamMessage(stream: otherStream));
     checkNotNotified();
     check(model).messages.length.equals(30);
   });
@@ -390,8 +388,7 @@ void main() {
   test('MessageEvent, before fetch', () async {
     final stream = eg.stream();
     await prepare(narrow: ChannelNarrow(stream.streamId));
-    await store.handleEvent(MessageEvent(id: 0,
-      message: eg.streamMessage(stream: stream)));
+    await store.addMessage(eg.streamMessage(stream: stream));
     checkNotNotified();
     check(model).fetched.isFalse();
   });
@@ -1314,7 +1311,7 @@ void main() {
       }
 
       final message = eg.streamMessage(stream: stream, topic: 'hello');
-      await store.handleEvent(MessageEvent(id: 0, message: message));
+      await store.addMessage(message);
 
       await store.handleEvent(
         eg.reactionEvent(eg.unicodeEmojiReaction, ReactionOp.add, message.id));
@@ -1396,8 +1393,7 @@ void main() {
     await prepare(narrow: ChannelNarrow(stream.streamId));
     await prepareMessages(foundOldest: true, messages:
       List.generate(30, (i) => eg.streamMessage(stream: stream)));
-    await store.handleEvent(MessageEvent(id: 0,
-      message: eg.streamMessage(stream: stream)));
+    await store.addMessage(eg.streamMessage(stream: stream));
     checkNotifiedOnce();
     check(model).messages.length.equals(31);
 
@@ -1454,28 +1450,28 @@ void main() {
         .deepEquals(expected..insertAll(0, [101, 103, 105]));
 
       // … and on MessageEvent.
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 301, stream: stream1, topic: 'A')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 301, stream: stream1, topic: 'A')));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(301));
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 302, stream: stream1, topic: 'B')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 302, stream: stream1, topic: 'B')));
       checkNotNotified();
       check(model.messages.map((m) => m.id)).deepEquals(expected);
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 303, stream: stream2, topic: 'C')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 303, stream: stream2, topic: 'C')));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(303));
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 304, stream: stream2, topic: 'D')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 304, stream: stream2, topic: 'D')));
       checkNotNotified();
       check(model.messages.map((m) => m.id)).deepEquals(expected);
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.dmMessage(id: 305, from: eg.otherUser, to: [eg.selfUser])));
+      await store.handleEvent(eg.messageEvent(
+        eg.dmMessage(id: 305, from: eg.otherUser, to: [eg.selfUser])));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(305));
     });
@@ -1511,18 +1507,18 @@ void main() {
         .deepEquals(expected..insertAll(0, [101, 102]));
 
       // … and on MessageEvent.
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 301, stream: stream, topic: 'A')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 301, stream: stream, topic: 'A')));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(301));
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 302, stream: stream, topic: 'B')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 302, stream: stream, topic: 'B')));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(302));
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 303, stream: stream, topic: 'C')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 303, stream: stream, topic: 'C')));
       checkNotNotified();
       check(model.messages.map((m) => m.id)).deepEquals(expected);
     });
@@ -1553,8 +1549,8 @@ void main() {
         .deepEquals(expected..insertAll(0, [101]));
 
       // … and on MessageEvent.
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(id: 301, stream: stream, topic: 'A')));
+      await store.handleEvent(eg.messageEvent(
+        eg.streamMessage(id: 301, stream: stream, topic: 'A')));
       checkNotifiedOnce();
       check(model.messages.map((m) => m.id)).deepEquals(expected..add(301));
     });
@@ -1593,7 +1589,7 @@ void main() {
       // … and on MessageEvent.
       final messages = getMessages(301);
       for (var i = 0; i < 3; i += 1) {
-        await store.handleEvent(MessageEvent(id: 0, message: messages[i]));
+        await store.handleEvent(eg.messageEvent(messages[i]));
         checkNotifiedOnce();
         check(model.messages.map((m) => m.id)).deepEquals(expected..add(301 + i));
       }
@@ -1631,7 +1627,7 @@ void main() {
       // … and on MessageEvent.
       final messages = getMessages(301);
       for (var i = 0; i < 2; i += 1) {
-        await store.handleEvent(MessageEvent(id: 0, message: messages[i]));
+        await store.handleEvent(eg.messageEvent(messages[i]));
         checkNotifiedOnce();
         check(model.messages.map((m) => m.id)).deepEquals(expected..add(301 + i));
       }
@@ -1644,8 +1640,7 @@ void main() {
       await prepare(narrow: ChannelNarrow(stream.streamId));
       await prepareMessages(foundOldest: true, messages: []);
 
-      await store.handleEvent(MessageEvent(id: 0,
-        message: eg.streamMessage(stream: stream)));
+      await store.addMessage(eg.streamMessage(stream: stream));
       // Each [checkNotifiedOnce] call ensures there's been a [checkInvariants]
       // call, where the [ContentNode] gets checked.  The additional checks to
       // make this test explicit.
@@ -1659,13 +1654,13 @@ void main() {
       await prepare(narrow: ChannelNarrow(stream.streamId));
       await prepareMessages(foundOldest: true, messages: []);
 
-      await store.handleEvent(MessageEvent(id: 0, message: eg.streamMessage(
+      await store.addMessage(eg.streamMessage(
         stream: stream,
         sender: eg.selfUser,
         submessages: [
           eg.submessage(senderId: eg.selfUser.userId,
             content: eg.pollWidgetData(question: 'question', options: ['A'])),
-        ])));
+        ]));
       // Each [checkNotifiedOnce] call ensures there's been a [checkInvariants]
       // call, where the value of the [Poll] gets checked.  The additional
       // checks make this test explicit.
@@ -1723,11 +1718,11 @@ void main() {
     checkNotified(count: 2);
 
     // Then test MessageEvent, where a new header is needed…
-    await store.handleEvent(MessageEvent(id: 0, message: streamMessage(13)));
+    await store.handleEvent(eg.messageEvent(streamMessage(13)));
     checkNotifiedOnce();
 
     // … and where it's not.
-    await store.handleEvent(MessageEvent(id: 0, message: streamMessage(14)));
+    await store.handleEvent(eg.messageEvent(streamMessage(14)));
     checkNotifiedOnce();
 
     // Then test UpdateMessageEvent edits, where a header is and remains needed…
diff --git a/test/model/message_test.dart b/test/model/message_test.dart
index 9c9a940d42..5b4457f30b 100644
--- a/test/model/message_test.dart
+++ b/test/model/message_test.dart
@@ -71,9 +71,7 @@ void main() {
   }
 
   Future<void> addMessages(Iterable<Message> messages) async {
-    for (final m in messages) {
-      await store.handleEvent(MessageEvent(id: 0, message: m));
-    }
+    await store.addMessages(messages);
     checkNotified(count: messageList.fetched ? messages.length : 0);
   }
 
@@ -131,7 +129,7 @@ void main() {
       check(store.messages).isEmpty();
 
       final newMessage = eg.streamMessage();
-      await store.handleEvent(MessageEvent(id: 1, message: newMessage));
+      await store.handleEvent(eg.messageEvent(newMessage));
       check(store.messages).deepEquals({
         newMessage.id: newMessage,
       });
@@ -150,7 +148,7 @@ void main() {
       });
 
       final newMessage = eg.streamMessage();
-      await store.handleEvent(MessageEvent(id: 1, message: newMessage));
+      await store.handleEvent(eg.messageEvent(newMessage));
       check(store.messages).deepEquals({
         for (final m in messages) m.id: m,
         newMessage.id: newMessage,
@@ -164,7 +162,7 @@ void main() {
       check(store.messages).deepEquals({1: message});
 
       final newMessage = eg.streamMessage(id: 1, content: '<p>bar</p>');
-      await store.handleEvent(MessageEvent(id: 1, message: newMessage));
+      await store.handleEvent(eg.messageEvent(newMessage));
       check(store.messages).deepEquals({1: newMessage});
     });
   });
@@ -861,7 +859,7 @@ void main() {
         ]);
 
         await prepare();
-        await store.handleEvent(MessageEvent(id: 0, message: message));
+        await store.handleEvent(eg.messageEvent(message));
       }
 
       test('smoke', () async {
@@ -932,7 +930,7 @@ void main() {
           ),
         ]);
         await prepare();
-        await store.handleEvent(MessageEvent(id: 0, message: message));
+        await store.handleEvent(eg.messageEvent(message));
         check(store.messages[message.id]).isNotNull().poll.isNull();
       });
     });
diff --git a/test/model/recent_dm_conversations_test.dart b/test/model/recent_dm_conversations_test.dart
index f66b38c633..da487304e6 100644
--- a/test/model/recent_dm_conversations_test.dart
+++ b/test/model/recent_dm_conversations_test.dart
@@ -1,6 +1,5 @@
 import 'package:checks/checks.dart';
 import 'package:test/scaffolding.dart';
-import 'package:zulip/api/model/events.dart';
 import 'package:zulip/api/model/initial_snapshot.dart';
 import 'package:zulip/model/narrow.dart';
 import 'package:zulip/model/recent_dm_conversations.dart';
@@ -66,7 +65,7 @@ void main() {
         final expected = setupView();
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: eg.streamMessage()))
+          ..handleMessageEvent(eg.messageEvent(eg.streamMessage()))
         ) ..map.deepEquals(expected.map)
           ..sorted.deepEquals(expected.sorted)
           ..latestMessagesByRecipient.deepEquals(expected.latestMessagesByRecipient);
@@ -78,7 +77,7 @@ void main() {
         final message = eg.dmMessage(id: 300, from: eg.selfUser, to: [eg.user(userId: 2)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([2]):    300,
             key([1]):    200,
@@ -94,7 +93,7 @@ void main() {
         final message = eg.dmMessage(id: 150, from: eg.selfUser, to: [eg.user(userId: 2)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([1]):    200,
             key([2]):    150,
@@ -111,7 +110,7 @@ void main() {
           to: [eg.user(userId: 1), eg.user(userId: 2)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([1, 2]): 300,
             key([1]):    200,
@@ -126,7 +125,7 @@ void main() {
         final message = eg.dmMessage(id: 300, from: eg.selfUser, to: [eg.user(userId: 1)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([1]):    300,
             key([1, 2]): 100,
@@ -143,7 +142,7 @@ void main() {
         final expected = setupView();
         check(setupView()
           // ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals(expected.map)
           ..sorted.deepEquals(expected.sorted)
           ..latestMessagesByRecipient.deepEquals(expected.latestMessagesByRecipient);
@@ -157,7 +156,7 @@ void main() {
           to: [eg.user(userId: 1), eg.user(userId: 3)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([1, 3]): 300,
             key([1]):    200,
@@ -174,7 +173,7 @@ void main() {
           to: [eg.user(userId: 1), eg.user(userId: 3)]);
         check(setupView()
           ..addListener(() { listenersNotified = true; })
-          ..handleMessageEvent(MessageEvent(id: 1, message: message))
+          ..handleMessageEvent(eg.messageEvent(message))
         ) ..map.deepEquals({
             key([1]):    200,
             key([1, 3]): 150,
diff --git a/test/model/test_store.dart b/test/model/test_store.dart
index 6f13845cf5..0196611e1d 100644
--- a/test/model/test_store.dart
+++ b/test/model/test_store.dart
@@ -288,7 +288,7 @@ extension PerAccountStoreTestExtension on PerAccountStore {
   }
 
   Future<void> addMessage(Message message) async {
-    await handleEvent(MessageEvent(id: 1, message: message));
+    await handleEvent(eg.messageEvent(message));
   }
 
   Future<void> addMessages(Iterable<Message> messages) async {
diff --git a/test/model/unreads_test.dart b/test/model/unreads_test.dart
index 9a2e899ba7..e8f7a0f850 100644
--- a/test/model/unreads_test.dart
+++ b/test/model/unreads_test.dart
@@ -49,7 +49,7 @@ void main() {
 
   void fillWithMessages(Iterable<Message> messages) {
     for (final message in messages) {
-      model.handleMessageEvent(MessageEvent(id: 0, message: message));
+      model.handleMessageEvent(eg.messageEvent(message));
     }
     notifiedCount = 0;
   }
@@ -318,7 +318,7 @@ void main() {
         final message = isStream
           ? eg.streamMessage(flags: flags)
           : eg.dmMessage(from: eg.otherUser, to: [eg.selfUser], flags: flags);
-        model.handleMessageEvent(MessageEvent(id: 0, message: message));
+        model.handleMessageEvent(eg.messageEvent(message));
         if (isUnread) {
           checkNotifiedOnce();
         }
@@ -346,7 +346,7 @@ void main() {
 
             prepare();
             fillWithMessages([oldMessage]);
-            model.handleMessageEvent(MessageEvent(id: 0, message: newMessage));
+            model.handleMessageEvent(eg.messageEvent(newMessage));
             checkNotifiedOnce();
             checkMatchesMessages([oldMessage, newMessage]);
           });
@@ -369,7 +369,7 @@ void main() {
             final message = eg.dmMessage(from: from, to: to, flags: []);
 
             prepare();
-            model.handleMessageEvent(MessageEvent(id: 0, message: message));
+            model.handleMessageEvent(eg.messageEvent(message));
             checkNotifiedOnce();
             checkMatchesMessages([message]);
           });
@@ -387,7 +387,7 @@ void main() {
             test('existing in $oldDesc narrow; new in ${oldNarrow == newNarrow ? 'same narrow' : 'different narrow ($newDesc)'}', () {
               prepare();
               fillWithMessages([oldMessage]);
-              model.handleMessageEvent(MessageEvent(id: 0, message: newMessage));
+              model.handleMessageEvent(eg.messageEvent(newMessage));
               checkNotifiedOnce();
               checkMatchesMessages([oldMessage, newMessage]);
             });
diff --git a/test/widgets/home_test.dart b/test/widgets/home_test.dart
index e940d2ce77..3c8db1dfcf 100644
--- a/test/widgets/home_test.dart
+++ b/test/widgets/home_test.dart
@@ -2,7 +2,6 @@ import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_checks/flutter_checks.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:zulip/api/model/events.dart';
 import 'package:zulip/model/actions.dart';
 import 'package:zulip/model/narrow.dart';
 import 'package:zulip/model/store.dart';
@@ -72,8 +71,8 @@ void main () {
     testWidgets('preserve states when switching between views', (tester) async {
       await prepare(tester);
       await store.addUser(eg.otherUser);
-      await store.handleEvent(MessageEvent(
-        id: 0, message: eg.dmMessage(from: eg.otherUser, to: [eg.selfUser])));
+      await store.addMessage(
+        eg.dmMessage(from: eg.otherUser, to: [eg.selfUser]));
       await tester.pump();
 
       check(find.byIcon(ZulipIcons.arrow_down)).findsExactly(2);
diff --git a/test/widgets/inbox_test.dart b/test/widgets/inbox_test.dart
index 7b2be9176e..9fa5de1bf3 100644
--- a/test/widgets/inbox_test.dart
+++ b/test/widgets/inbox_test.dart
@@ -70,7 +70,7 @@ void main() {
 
     for (final message in unreadMessages) {
       assert(!message.flags.contains(MessageFlag.read));
-      await store.handleEvent(MessageEvent(id: 1, message: message));
+      await store.addMessage(message);
     }
 
     await tester.pumpWidget(TestZulipApp(
diff --git a/test/widgets/message_list_test.dart b/test/widgets/message_list_test.dart
index b20aaefca9..53ad1334ef 100644
--- a/test/widgets/message_list_test.dart
+++ b/test/widgets/message_list_test.dart
@@ -1481,7 +1481,7 @@ void main() {
 
       // introduce new message
       final newMessage = eg.streamMessage(flags:[MessageFlag.read]);
-      await store.handleEvent(MessageEvent(id: 0, message: newMessage));
+      await store.handleEvent(eg.messageEvent(newMessage));
       await tester.pump(); // process handleEvent
       check(find.byType(MessageItem).evaluate()).length.equals(2);
       check(getAnimation(tester, message.id))
diff --git a/test/widgets/poll_test.dart b/test/widgets/poll_test.dart
index bd6ae3f92f..a6bd74c77e 100644
--- a/test/widgets/poll_test.dart
+++ b/test/widgets/poll_test.dart
@@ -5,7 +5,6 @@ import 'package:http/http.dart' as http;
 import 'package:flutter/widgets.dart';
 import 'package:flutter_checks/flutter_checks.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:zulip/api/model/events.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/api/model/submessage.dart';
 import 'package:zulip/model/store.dart';
@@ -40,7 +39,7 @@ void main() {
     message = eg.streamMessage(
       sender: eg.selfUser,
       submessages: [eg.submessage(content: submessageContent)]);
-    await store.handleEvent(MessageEvent(id: 0, message: message));
+    await store.addMessage(message);
     await tester.pumpWidget(TestZulipApp(accountId: eg.selfAccount.id,
       child: PollWidget(messageId: message.id, poll: message.poll!)));
     await tester.pump();
diff --git a/test/widgets/recent_dm_conversations_test.dart b/test/widgets/recent_dm_conversations_test.dart
index 0d440accec..44322ccea1 100644
--- a/test/widgets/recent_dm_conversations_test.dart
+++ b/test/widgets/recent_dm_conversations_test.dart
@@ -38,9 +38,7 @@ Future<void> setupPage(WidgetTester tester, {
     await store.addUser(user);
   }
 
-  for (final dmMessage in dmMessages) {
-    await store.handleEvent(MessageEvent(id: 1, message: dmMessage));
-  }
+  await store.addMessages(dmMessages);
 
   if (newNameForSelfUser != null) {
     await store.handleEvent(RealmUserUpdateEvent(id: 1, userId: eg.selfUser.userId,