feat(messaging): add FID registration APIs

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingPlugin.java

@@ -55,6 +55,12 @@ public class FlutterFirebaseMessagingPlugin
   private Observer<RemoteMessage> remoteMessageObserver;
   private final LiveData<String> liveDataToken = FlutterFirebaseTokenLiveData.getInstance();
   private Observer<String> tokenObserver;
+  private final LiveData<String> liveDataRegistered =
+      FlutterFirebaseRegisteredLiveData.getInstance();
+  private Observer<String> registeredObserver;
+  private final LiveData<String> liveDataUnregistered =
+      FlutterFirebaseUnregisteredLiveData.getInstance();
+  private Observer<String> unregisteredObserver;
 
   private RemoteMessage initialMessage;
   // We store the initial notification in a separate variable
@@ -77,10 +83,14 @@ private void initInstance(BinaryMessenger messenger) {
           channel.invokeMethod("Messaging#onMessage", content);
         };
     tokenObserver = token -> channel.invokeMethod("Messaging#onTokenRefresh", token);
+    registeredObserver = fid -> channel.invokeMethod("Messaging#onRegistered", fid);
+    unregisteredObserver = fid -> channel.invokeMethod("Messaging#onUnregistered", fid);
     // We remove these observers in the onDetachedFromEngine method. Using "observeForever()"
     // allows us to use without a LifecycleOwner.
     liveDataRemoteMessage.observeForever(remoteMessageObserver);
     liveDataToken.observeForever(tokenObserver);
+    liveDataRegistered.observeForever(registeredObserver);
+    liveDataUnregistered.observeForever(unregisteredObserver);
 
     registerPlugin(channelName, this);
   }
@@ -95,6 +105,8 @@ public void onAttachedToEngine(FlutterPluginBinding binding) {
   public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
     liveDataToken.removeObserver(tokenObserver);
     liveDataRemoteMessage.removeObserver(remoteMessageObserver);
+    liveDataRegistered.removeObserver(registeredObserver);
+    liveDataUnregistered.removeObserver(unregisteredObserver);
   }
 
   @Override
@@ -163,6 +175,38 @@ private Task<Map<String, Object>> getToken() {
     return taskCompletionSource.getTask();
   }
 
+  private Task<Void> register() {
+    TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
+
+    cachedThreadPool.execute(
+        () -> {
+          try {
+            Tasks.await(FirebaseMessaging.getInstance().register());
+            taskCompletionSource.setResult(null);
+          } catch (Exception e) {
+            taskCompletionSource.setException(e);
+          }
+        });
+
+    return taskCompletionSource.getTask();
+  }
+
+  private Task<Void> unregister() {
+    TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
+
+    cachedThreadPool.execute(
+        () -> {
+          try {
+            Tasks.await(FirebaseMessaging.getInstance().unregister());
+            taskCompletionSource.setResult(null);
+          } catch (Exception e) {
+            taskCompletionSource.setException(e);
+          }
+        });
+
+    return taskCompletionSource.getTask();
+  }
+
   private Task<Void> subscribeToTopic(Map<String, Object> arguments) {
     TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
 
@@ -482,6 +526,12 @@ public void onMethodCall(final MethodCall call, @NonNull final Result result) {
       case "Messaging#getToken":
         methodCallTask = getToken();
         break;
+      case "Messaging#register":
+        methodCallTask = register();
+        break;
+      case "Messaging#unregister":
+        methodCallTask = unregister();
+        break;
       case "Messaging#subscribeToTopic":
         methodCallTask = subscribeToTopic(call.arguments());
         break;

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseMessagingService.java

@@ -14,6 +14,16 @@ public void onNewToken(@NonNull String token) {
     FlutterFirebaseTokenLiveData.getInstance().postToken(token);
   }
 
+  @Override
+  public void onRegistered(@NonNull String installationId) {
+    FlutterFirebaseRegisteredLiveData.getInstance().postFid(installationId);
+  }
+
+  @Override
+  public void onUnregistered(@NonNull String installationId) {
+    FlutterFirebaseUnregisteredLiveData.getInstance().postFid(installationId);
+  }
+
   @Override
   public void onMessageReceived(@NonNull RemoteMessage remoteMessage) {
     // Added for commenting purposes;

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseRegisteredLiveData.java

@@ -0,0 +1,22 @@
+// Copyright 2026 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.firebase.messaging;
+
+import androidx.lifecycle.LiveData;
+
+public class FlutterFirebaseRegisteredLiveData extends LiveData<String> {
+  private static FlutterFirebaseRegisteredLiveData instance;
+
+  public static FlutterFirebaseRegisteredLiveData getInstance() {
+    if (instance == null) {
+      instance = new FlutterFirebaseRegisteredLiveData();
+    }
+    return instance;
+  }
+
+  public void postFid(String fid) {
+    postValue(fid);
+  }
+}

packages/firebase_messaging/firebase_messaging/android/src/main/java/io/flutter/plugins/firebase/messaging/FlutterFirebaseUnregisteredLiveData.java

@@ -0,0 +1,22 @@
+// Copyright 2026 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.firebase.messaging;
+
+import androidx.lifecycle.LiveData;
+
+public class FlutterFirebaseUnregisteredLiveData extends LiveData<String> {
+  private static FlutterFirebaseUnregisteredLiveData instance;
+
+  public static FlutterFirebaseUnregisteredLiveData getInstance() {
+    if (instance == null) {
+      instance = new FlutterFirebaseUnregisteredLiveData();
+    }
+    return instance;
+  }
+
+  public void postFid(String fid) {
+    postValue(fid);
+  }
+}

packages/firebase_messaging/firebase_messaging/example/ios/Runner/Info.plist

@@ -20,6 +20,8 @@
 	<string>????</string>
 	<key>CFBundleVersion</key>
 	<string>$(FLUTTER_BUILD_NUMBER)</string>
+	<key>FirebaseMessagingInstallationIdEnabled</key>
+	<true/>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UIBackgroundModes</key>

packages/firebase_messaging/firebase_messaging/example/lib/main.dart

@@ -28,13 +28,13 @@ import 'token_monitor.dart';
 /// 2. Run `melos bootstrap` in FlutterFire project.
 /// 3. In your terminal, root to ./packages/firebase_messaging/firebase_messaging/example directory.
 /// 4. Run `flutterfire configure` in the example/ directory to setup your app with your Firebase project.
-/// 5. Open `token_monitor.dart` and change `vapidKey` to yours.
+/// 5. Open `token_monitor.dart` and change `messagingVapidKey` to yours.
 /// 6. Run the app on an actual device for iOS, android is fine to run on an emulator.
 /// 7. Use the following script to send a message to your device: scripts/send-message.js. To run this script,
 ///    you will need nodejs installed on your computer. Then the following:
 ///     a. Download a service account key (JSON file) from your Firebase console, rename it to "google-services.json" and add to the example/scripts directory.
 ///     b. Ensure your device/emulator is running, and run the FirebaseMessaging example app using `flutter run`.
-///     c. Copy the token that is printed in the console and paste it here: https://github.com/firebase/flutterfire/blob/01b4d357e1/packages/firebase_messaging/firebase_messaging/example/lib/main.dart#L32
+///     c. Copy the FID that is printed in the console and paste it here: https://github.com/firebase/flutterfire/blob/01b4d357e1/packages/firebase_messaging/firebase_messaging/example/lib/main.dart#L32
 ///     c. From your terminal, root to example/scripts directory & run `npm install`.
 ///     d. Run `npm run send-message` in the example/scripts directory and your app will receive messages in any state; foreground, background, terminated.
 ///  Note: Flutter API documentation for receiving messages: https://firebase.google.com/docs/cloud-messaging/flutter/receive
@@ -150,10 +150,10 @@ class MessagingExampleApp extends StatelessWidget {
 int _messageCount = 0;
 
 /// The API endpoint here accepts a raw FCM payload for demonstration purposes.
-String constructFCMPayload(String? token) {
+String constructFCMPayload(String? fid) {
   _messageCount++;
   return jsonEncode({
-    'token': token,
+    'fid': fid,
     'data': {
       'via': 'FlutterFire Cloud Messaging!!!',
       'count': _messageCount.toString(),
@@ -172,7 +172,7 @@ class Application extends StatefulWidget {
 }
 
 class _Application extends State<Application> {
-  String? _token;
+  String? _fid;
   String? initialMessage;
   bool _resolved = false;
 
@@ -205,8 +205,8 @@ class _Application extends State<Application> {
   }
 
   Future<void> sendPushMessage() async {
-    if (_token == null) {
-      print('Unable to send FCM message, no token exists.');
+    if (_fid == null) {
+      print('Unable to send FCM message, no FID exists.');
       return;
     }
 
@@ -216,7 +216,7 @@ class _Application extends State<Application> {
         headers: <String, String>{
           'Content-Type': 'application/json; charset=UTF-8',
         },
-        body: constructFCMPayload(_token),
+        body: constructFCMPayload(_fid),
       );
       print('FCM request for device sent!');
     } catch (e) {
@@ -248,6 +248,26 @@ class _Application extends State<Application> {
           );
         }
         break;
+      case 'register':
+        {
+          print('FlutterFire Messaging Example: Registering with FCM.');
+          await FirebaseMessaging.instance.register(
+            vapidKey: messagingVapidKey,
+          );
+          print(
+            'FlutterFire Messaging Example: Registering with FCM successful.',
+          );
+        }
+        break;
+      case 'unregister':
+        {
+          print('FlutterFire Messaging Example: Unregistering from FCM.');
+          await FirebaseMessaging.instance.unregister();
+          print(
+            'FlutterFire Messaging Example: Unregistering from FCM successful.',
+          );
+        }
+        break;
       case 'get_apns_token':
         {
           if (defaultTargetPlatform == TargetPlatform.iOS ||
@@ -285,6 +305,14 @@ class _Application extends State<Application> {
                   value: 'unsubscribe',
                   child: Text('Unsubscribe to topic'),
                 ),
+                const PopupMenuItem(
+                  value: 'register',
+                  child: Text('Register with FCM'),
+                ),
+                const PopupMenuItem(
+                  value: 'unregister',
+                  child: Text('Unregister from FCM'),
+                ),
                 const PopupMenuItem(
                   value: 'get_apns_token',
                   child: Text('Get APNs token (Apple only)'),
@@ -315,15 +343,36 @@ class _Application extends State<Application> {
               ),
             ),
             MetaCard(
-              'FCM Token',
-              TokenMonitor((token) {
-                _token = token;
-                return token == null
-                    ? const CircularProgressIndicator()
-                    : SelectableText(
-                        token,
+              'FCM Registration FID',
+              RegistrationMonitor((fid) {
+                _fid = fid;
+                return Column(
+                  children: [
+                    if (fid == null)
+                      const Text('No FID registered yet.')
+                    else
+                      SelectableText(
+                        fid,
                         style: const TextStyle(fontSize: 12),
-                      );
+                      ),
+                    const SizedBox(height: 12),
+                    Wrap(
+                      spacing: 8,
+                      runSpacing: 8,
+                      alignment: WrapAlignment.center,
+                      children: [
+                        ElevatedButton(
+                          onPressed: () => onActionSelected('register'),
+                          child: const Text('Register with FCM'),
+                        ),
+                        ElevatedButton(
+                          onPressed: () => onActionSelected('unregister'),
+                          child: const Text('Unregister from FCM'),
+                        ),
+                      ],
+                    ),
+                  ],
+                );
               }),
             ),
             ElevatedButton(

packages/firebase_messaging/firebase_messaging/example/lib/token_monitor.dart

@@ -4,47 +4,73 @@
 
 // ignore_for_file: require_trailing_commas
 
+import 'dart:async';
+
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/material.dart';
 
-/// Manages & returns the users FCM token.
+/// Web push certificate key used by the example app.
+///
+/// This is only required by web, and is ignored on other platforms.
+const String messagingVapidKey = 'VAPID_KEY';
+
+/// Manages and returns the app instance FCM registration FID.
 ///
-/// Also monitors token refreshes and updates state.
-class TokenMonitor extends StatefulWidget {
+/// Also monitors registration changes and updates state.
+class RegistrationMonitor extends StatefulWidget {
   // ignore: public_member_api_docs
-  TokenMonitor(this._builder);
+  RegistrationMonitor(this._builder);
 
-  final Widget Function(String? token) _builder;
+  final Widget Function(String? fid) _builder;
 
   @override
-  State<StatefulWidget> createState() => _TokenMonitor();
+  State<StatefulWidget> createState() => _RegistrationMonitor();
 }
 
-class _TokenMonitor extends State<TokenMonitor> {
-  String? _token;
-  late Stream<String> _tokenStream;
+class _RegistrationMonitor extends State<RegistrationMonitor> {
+  String? _fid;
+  StreamSubscription<String>? _registeredSubscription;
+  StreamSubscription<String>? _unregisteredSubscription;
 
-  void setToken(String? token) {
-    print('FCM Token: $token');
+  void setRegisteredFid(String fid) {
+    print('FCM registered FID: $fid');
     setState(() {
-      _token = token;
+      _fid = fid;
+    });
+  }
+
+  void setUnregisteredFid(String fid) {
+    print('FCM unregistered FID: $fid');
+    setState(() {
+      if (_fid == fid) {
+        _fid = null;
+      }
     });
   }
 
   @override
   void initState() {
     super.initState();
+    _registeredSubscription =
+        FirebaseMessaging.instance.onRegistered.listen(setRegisteredFid);
+    _unregisteredSubscription =
+        FirebaseMessaging.instance.onUnregistered.listen(setUnregisteredFid);
     FirebaseMessaging.instance
-        .getToken(
-            vapidKey:
-                'BNKkaUWxyP_yC_lki1kYazgca0TNhuzt2drsOrL6WrgGbqnMnr8ZMLzg_rSPDm6HKphABS0KzjPfSqCXHXEd06Y')
-        .then(setToken);
-    _tokenStream = FirebaseMessaging.instance.onTokenRefresh;
-    _tokenStream.listen(setToken);
+        .register(vapidKey: messagingVapidKey)
+        .catchError((Object error) {
+      print('FCM registration failed: $error');
+    });
+  }
+
+  @override
+  void dispose() {
+    _registeredSubscription?.cancel();
+    _unregisteredSubscription?.cancel();
+    super.dispose();
   }
 
   @override
   Widget build(BuildContext context) {
-    return widget._builder(_token);
+    return widget._builder(_fid);
   }
 }