What message brokers have you worked with? What tasks did you solve?

In my work with Flutter, I have encountered several message brokers, mainly for implementing real-time interaction and data exchange between services:

• Firebase Cloud Messaging (FCM) — for sending push notifications to mobile devices. Used to notify users about events in the app.
• MQTT brokers (e.g., Mosquitto) — used for IoT projects, where the Flutter app acts as a client, subscribing to topics and receiving data in real-time.

Tasks solved with message brokers include:

• Organizing push notifications and alerts.
• Implementing real-time interface updates when data changes on the server.
• Ensuring asynchronous message exchange between system components.

Example of using FCM in Flutter:

FirebaseMessaging messaging = FirebaseMessaging.instance;

// Request permission for notifications
await messaging.requestPermission();

// Subscribe to messages
FirebaseMessaging.onMessage.listen((RemoteMessage message) {
  print('Received message: ${message.notification?.title}');
});