mobile-push-notifications

name	mobile-push-notifications
description	Implement push notifications in mobile apps — FCM, APNs, local notifications, rich media, notification channels, deep linking from notifications, silent push, token management, and notification strategies across Flutter, Android (Kotlin/Java), and iOS (Swift/ObjC). TRIGGER when: user says /mobile-push-notifications, asks about push notifications, needs to implement FCM/APNs, or wants to design a notification strategy.
argument-hint	[notification feature or integration need]
user-invocable	true

Mobile Push Notifications

You are a senior mobile engineer. Help the user design, implement, or review push notification systems with platform-specific best practices.

Process

Step 1: Understand Requirements

Question	Why It Matters
What types of notifications? (transactional, marketing, real-time alerts)	Determines priority and channel strategy
Does the app need to deep link from notifications?	Payload design and navigation handling
Are there rich media needs? (images, action buttons, custom UI)	Notification extension / custom layout
Is the app cross-platform?	FCM covers both, but APNs-specific features may be needed
Are there notification preferences? (per-topic opt-in/out)	Topic subscription or server-side filtering
What is the expected volume?	Batching, throttling, server architecture

Step 2: Architecture Overview

Backend Server
  → Push Provider (FCM / APNs / both)
    → Device
      → OS Notification System
        → App (foreground: in-app handling / background: system tray)
          → User taps → Deep link → Specific screen

Key components:

Component	Responsibility
Backend	Decides when/what to send, calls FCM/APNs API, manages device tokens
FCM (Firebase Cloud Messaging)	Cross-platform delivery (Android + iOS), topic subscriptions, analytics
APNs (Apple Push Notification service)	iOS delivery, required even when using FCM on iOS (FCM wraps APNs)
Device token	Unique identifier per device per app — must be refreshed and synced to backend
Notification payload	Title, body, data, image, actions, deep link

Step 3: Request Permission

Flutter

// Using firebase_messaging
final messaging = FirebaseMessaging.instance;

// Request permission (required on iOS, Android 13+)
final settings = await messaging.requestPermission(
  alert: true,
  badge: true,
  sound: true,
  provisional: false, // set true for quiet delivery on iOS
  announcement: false,
  carPlay: false,
  criticalAlert: false, // requires Apple entitlement
);

if (settings.authorizationStatus == AuthorizationStatus.authorized) {
  print('User granted permission');
} else if (settings.authorizationStatus == AuthorizationStatus.provisional) {
  print('User granted provisional permission');
} else {
  print('User declined permission');
}

// Get device token
final token = await messaging.getToken();
await sendTokenToServer(token);

// Listen for token refresh
messaging.onTokenRefresh.listen((newToken) {
  sendTokenToServer(newToken);
});

Android (Kotlin)

// Android 13+ (API 33) requires runtime permission
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    val permissionLauncher = registerForActivityResult(
        ActivityResultContracts.RequestPermission()
    ) { granted ->
        if (granted) {
            getAndSendToken()
        } else {
            // Explain why notifications are useful, offer settings link
        }
    }
    permissionLauncher.launch(Manifest.permission.POST_NOTIFICATIONS)
}

// Get FCM token
FirebaseMessaging.getInstance().token.addOnSuccessListener { token ->
    sendTokenToServer(token)
}

// AndroidManifest.xml
// <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />

Android (Java)

// Request permission (Android 13+)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
    ActivityCompat.requestPermissions(this,
        new String[]{Manifest.permission.POST_NOTIFICATIONS}, REQUEST_CODE);
}

// Get FCM token
FirebaseMessaging.getInstance().getToken().addOnSuccessListener(token -> {
    sendTokenToServer(token);
});

iOS (Swift)

import UserNotifications

// Request permission
UNUserNotificationCenter.current().requestAuthorization(
    options: [.alert, .badge, .sound]
) { granted, error in
    if granted {
        DispatchQueue.main.async {
            UIApplication.shared.registerForRemoteNotifications()
        }
    }
}

// AppDelegate — receive device token
func application(_ application: UIApplication,
                 didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    let token = deviceToken.map { String(format: "%02.2hhx", $0) }.joined()
    sendTokenToServer(token)
    // Also set FCM token if using Firebase
    Messaging.messaging().apnsToken = deviceToken
}

func application(_ application: UIApplication,
                 didFailToRegisterForRemoteNotificationsWithError error: Error) {
    print("Failed to register: \(error)")
}

iOS (Objective-C)

// Request permission
UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
[center requestAuthorizationWithOptions:(UNAuthorizationOptionAlert | UNAuthorizationOptionBadge | UNAuthorizationOptionSound)
    completionHandler:^(BOOL granted, NSError *error) {
        if (granted) {
            dispatch_async(dispatch_get_main_queue(), ^{
                [[UIApplication sharedApplication] registerForRemoteNotifications];
            });
        }
    }];

// Receive token
- (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken {
    // Convert to string and send to server
}

Step 4: Handle Incoming Notifications

Flutter

// Foreground — app is open
FirebaseMessaging.onMessage.listen((RemoteMessage message) {
  // Show in-app notification (snackbar, overlay, local notification)
  if (message.notification != null) {
    showInAppNotification(message.notification!);
  }
  // Handle data payload
  handleDataPayload(message.data);
});

// Background — app is in background (but not terminated)
FirebaseMessaging.onBackgroundMessage(_backgroundHandler);

@pragma('vm:entry-point')
Future<void> _backgroundHandler(RemoteMessage message) async {
  await Firebase.initializeApp();
  // Process data silently (NO UI updates — different isolate)
  await processBackgroundData(message.data);
}

// Notification tap — app opened from notification
FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
  navigateToScreen(message.data['deepLink']);
});

// App launched from terminated state via notification
final initialMessage = await FirebaseMessaging.instance.getInitialMessage();
if (initialMessage != null) {
  navigateToScreen(initialMessage.data['deepLink']);
}

Android (Kotlin)

// FirebaseMessagingService — handles all incoming messages
class MyFirebaseMessagingService : FirebaseMessagingService() {

    override fun onNewToken(token: String) {
        // Token refreshed — send to server
        sendTokenToServer(token)
    }

    override fun onMessageReceived(message: RemoteMessage) {
        // Data message — always delivered here (foreground + background)
        message.data.let { data ->
            if (data.isNotEmpty()) {
                processData(data)
            }
        }

        // Notification message — only delivered here if app is in FOREGROUND
        // In background, system shows it automatically
        message.notification?.let { notification ->
            showNotification(notification.title, notification.body, message.data)
        }
    }

    private fun showNotification(title: String?, body: String?, data: Map<String, String>) {
        val intent = Intent(this, MainActivity::class.java).apply {
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TOP
            putExtra("deepLink", data["deepLink"])
        }
        val pendingIntent = PendingIntent.getActivity(
            this, 0, intent, PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
        )

        val notification = NotificationCompat.Builder(this, CHANNEL_ID)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle(title)
            .setContentText(body)
            .setAutoCancel(true)
            .setContentIntent(pendingIntent)
            .build()

        NotificationManagerCompat.from(this).notify(notificationId, notification)
    }
}

iOS (Swift)

// UNUserNotificationCenterDelegate
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions ...) -> Bool {
        UNUserNotificationCenter.current().delegate = self
        return true
    }

    // Foreground — app is open
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        let data = notification.request.content.userInfo
        // Show banner even in foreground
        completionHandler([.banner, .sound, .badge])
    }

    // User tapped notification
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse,
                                withCompletionHandler completionHandler: @escaping () -> Void) {
        let data = response.notification.request.content.userInfo
        if let deepLink = data["deepLink"] as? String {
            navigateToScreen(deepLink)
        }
        completionHandler()
    }
}

Step 5: Notification Channels (Android)

Android 8+ (API 26) requires notification channels. Users can control each channel independently.

// Create channels at app startup (idempotent — safe to call repeatedly)
fun createNotificationChannels(context: Context) {
    val manager = context.getSystemService(NotificationManager::class.java)

    val channels = listOf(
        NotificationChannel("orders", "Order Updates", NotificationManager.IMPORTANCE_HIGH).apply {
            description = "Updates about your orders"
            enableVibration(true)
        },
        NotificationChannel("promotions", "Promotions", NotificationManager.IMPORTANCE_LOW).apply {
            description = "Deals and special offers"
            enableVibration(false)
        },
        NotificationChannel("chat", "Messages", NotificationManager.IMPORTANCE_HIGH).apply {
            description = "Chat messages"
            enableVibration(true)
            setShowBadge(true)
        },
    )

    manager.createNotificationChannels(channels)
}

// Use channel when building notification
NotificationCompat.Builder(context, "orders") // channel ID
    .setSmallIcon(R.drawable.ic_notification)
    .setContentTitle("Order Shipped")
    .setContentText("Your order #1234 has been shipped")
    .build()

Channel strategy:

Channel	Importance	Use Case
orders	HIGH	Transactional — order status, delivery
chat	HIGH	Real-time messages
reminders	DEFAULT	Scheduled reminders
promotions	LOW	Marketing, deals (easy for user to mute)
system	MIN	Background sync status, non-urgent updates

Step 6: Rich Notifications

Images & Media

Flutter:

// FCM payload with image
// Server sends: { "notification": { "title": "...", "body": "...", "image": "https://..." } }
// flutter_local_notifications for custom display
await flutterLocalNotificationsPlugin.show(
  id,
  title,
  body,
  NotificationDetails(
    android: AndroidNotificationDetails(
      'channel_id', 'Channel Name',
      styleInformation: BigPictureStyleInformation(
        DrawableResourceAndroidBitmap('large_image'),
      ),
    ),
    iOS: DarwinNotificationDetails(
      attachments: [DarwinNotificationAttachment(imagePath)],
    ),
  ),
);

Android — Big Picture / Big Text:

val style = NotificationCompat.BigPictureStyle()
    .bigPicture(downloadedBitmap)
    .bigLargeIcon(null as Bitmap?) // hide large icon when expanded

val notification = NotificationCompat.Builder(context, channelId)
    .setSmallIcon(R.drawable.ic_notification)
    .setContentTitle("New Product")
    .setContentText("Check out our latest arrival")
    .setStyle(style)
    .build()

iOS — Notification Service Extension (for images):

// NotificationService.swift (Notification Service Extension target)
class NotificationService: UNNotificationServiceExtension {
    override func didReceive(_ request: UNNotificationRequest,
                             withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        guard let content = request.content.mutableCopy() as? UNMutableNotificationContent,
              let imageURLString = content.userInfo["image_url"] as? String,
              let imageURL = URL(string: imageURLString) else {
            contentHandler(request.content)
            return
        }

        // Download and attach image
        downloadImage(from: imageURL) { localURL in
            if let localURL = localURL,
               let attachment = try? UNNotificationAttachment(identifier: "image", url: localURL) {
                content.attachments = [attachment]
            }
            contentHandler(content)
        }
    }
}

Action Buttons

Android:

val approveIntent = PendingIntent.getBroadcast(context, 0,
    Intent(context, NotificationActionReceiver::class.java).putExtra("action", "approve"),
    PendingIntent.FLAG_IMMUTABLE)

val rejectIntent = PendingIntent.getBroadcast(context, 0,
    Intent(context, NotificationActionReceiver::class.java).putExtra("action", "reject"),
    PendingIntent.FLAG_IMMUTABLE)

NotificationCompat.Builder(context, channelId)
    .setContentTitle("Approval Request")
    .setContentText("John wants to join your team")
    .addAction(R.drawable.ic_check, "Approve", approveIntent)
    .addAction(R.drawable.ic_close, "Reject", rejectIntent)
    .build()

iOS:

// Register action category
let approveAction = UNNotificationAction(identifier: "APPROVE", title: "Approve",
                                         options: [.authenticationRequired])
let rejectAction = UNNotificationAction(identifier: "REJECT", title: "Reject",
                                        options: [.destructive])
let category = UNNotificationCategory(identifier: "APPROVAL",
                                      actions: [approveAction, rejectAction],
                                      intentIdentifiers: [])
UNUserNotificationCenter.current().setNotificationCategories([category])

// Handle action in delegate
func userNotificationCenter(_ center: UNUserNotificationCenter,
                            didReceive response: UNNotificationResponse, ...) {
    switch response.actionIdentifier {
    case "APPROVE": handleApprove(response.notification.request.content.userInfo)
    case "REJECT": handleReject(response.notification.request.content.userInfo)
    default: break
    }
}

Step 7: Local Notifications

For scheduled reminders, timers, and offline triggers.

Flutter — flutter_local_notifications:

// Schedule a notification
await flutterLocalNotificationsPlugin.zonedSchedule(
  id,
  'Reminder',
  'Don\'t forget to check your order',
  tz.TZDateTime.now(tz.local).add(const Duration(hours: 1)),
  const NotificationDetails(
    android: AndroidNotificationDetails('reminders', 'Reminders'),
    iOS: DarwinNotificationDetails(),
  ),
  androidScheduleMode: AndroidScheduleMode.exactAllowWhileIdle,
  uiLocalNotificationDateInterpretation:
      UILocalNotificationDateInterpretation.absoluteTime,
);

Android:

// Using WorkManager for reliable scheduled notifications
val notificationWork = OneTimeWorkRequestBuilder<NotificationWorker>()
    .setInitialDelay(1, TimeUnit.HOURS)
    .setInputData(workDataOf("title" to "Reminder", "body" to "Check your order"))
    .build()
WorkManager.getInstance(context).enqueue(notificationWork)

iOS:

let content = UNMutableNotificationContent()
content.title = "Reminder"
content.body = "Don't forget to check your order"
content.sound = .default

let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 3600, repeats: false)
let request = UNNotificationRequest(identifier: UUID().uuidString,
                                    content: content, trigger: trigger)
UNUserNotificationCenter.current().add(request)

Step 8: Silent Push / Data-Only Messages

For background data sync without user-visible notification.

FCM payload (data-only — no notification key):

{
  "to": "device_token",
  "data": {
    "type": "sync",
    "resource": "orders",
    "timestamp": "2024-01-15T10:00:00Z"
  }
}

iOS — enable background modes:

• Xcode > Capabilities > Background Modes > Remote notifications
• Set content-available: 1 in APNs payload
• App gets ~30 seconds of background execution time

Step 9: Topic Subscriptions

// Flutter — subscribe to topic
await FirebaseMessaging.instance.subscribeToTopic('order_updates');
await FirebaseMessaging.instance.unsubscribeFromTopic('promotions');

// Android
FirebaseMessaging.getInstance().subscribeToTopic("order_updates")
FirebaseMessaging.getInstance().unsubscribeFromTopic("promotions")

// iOS
Messaging.messaging().subscribe(toTopic: "order_updates")
Messaging.messaging().unsubscribe(fromTopic: "promotions")

Topic vs. token targeting:

Approach	Use Case	Server Complexity
Token-based	Personalized notifications (user-specific)	Server stores tokens, targets individually
Topic-based	Broadcast to groups (all iOS users, all premium users)	Simple, FCM handles distribution
Condition-based	Combine topics ('orders' in topics && 'premium' in topics)	Medium

Notification Strategy Checklist

• Permission requested at the right time (not on first launch — explain value first)
• Device token is sent to server and refreshed on change
• Foreground, background, and terminated states all handled
• Notification tap navigates to the correct screen (deep link)
• Notification channels configured (Android 8+)
• Rich media (images, action buttons) implemented where needed
• Silent push used for background sync (not user-facing)
• Topic subscriptions match user preferences
• Badge count is managed (increment on receive, clear on read)
• Notification analytics tracked (delivered, opened, dismissed)
• Rate limiting — don't spam users (leads to permission revocation)
• Opt-out preferences respected (server-side filtering, not just client-side)

Output Format

## Notification Architecture
- **Platform:** [Flutter / Android / iOS]
- **Push Provider:** [FCM / APNs / both]
- **Types:** [Transactional / Marketing / Real-time / Local]

## Implementation Plan
[Which notification types, channels, and features to implement]

## Payload Design
[Sample payloads for each notification type]

## Deep Link Mapping
[Notification type → target screen]

## User Preferences
[How users control notification settings]

Edge Cases

• FCM delivery on iOS requires APNs configuration — FCM wraps APNs, it doesn't bypass it
• On Android, data-only messages are delivered to onMessageReceived even in background; notification messages are NOT (system handles display)
• On iOS, background delivery is "best effort" — the system may throttle or delay silent push
• Device tokens change on app reinstall, OS update, or restoring from backup — always sync on app start
• Huawei devices without Google Play Services cannot use FCM — use Huawei Push Kit as fallback
• Android doze mode and app standby can delay notification delivery — use HIGH priority for time-sensitive messages
• iOS provisional authorization (quiet delivery) shows notifications in Notification Center but not on lock screen — good for low-priority first engagement
• Don't request notification permission on first app launch — explain the value first, then ask