Push Notifications
Push notifications let your server send messages to users' devices even when your app is closed. They're powerful for engagement — reminding users about activity, delivering time-sensitive information, or re-engaging inactive users. But they require careful implementation and respectful usage.
How Push Notifications Work
Push notifications flow through platform-specific services. Your server never connects directly to user devices. Instead:
Your Server → Push Service → User's Device → Your App
For iOS, Apple Push Notification service (APNs) handles delivery. For Android, Firebase Cloud Messaging (FCM) is the standard choice. FCM also supports iOS, making it popular for cross-platform apps.
The flow works like this: when your app launches, it registers with the push service and receives a unique device token. Your app sends this token to your server. When you want to notify that user, your server sends the message and token to the push service, which delivers it to the device.
Implementation Steps
1. Register for push permissions. Both platforms require user consent. iOS shows a permission dialog; Android grants permission by default but requires a runtime request for Android 13+.
2. Obtain the device token. After registration succeeds, the platform provides a token identifying this device. Tokens can change, so update your server whenever you receive a new one.
3. Send tokens to your server. Store tokens associated with user accounts. A user might have multiple devices, each with its own token.
4. Send notifications from your server. When something notification-worthy happens, your server sends a request to APNs or FCM with the message content and target tokens.
5. Handle notification taps. When users tap notifications, your app launches with context about which notification was tapped. Navigate them to relevant content.
Best Practices
Request permission at the right time. Don't ask immediately on first launch. Wait until users understand the value — after they've used the app and would benefit from notifications.
Provide clear value. Every notification should help the user. Messages from friends, order updates, and time-sensitive alerts are valuable. Marketing spam gets your app uninstalled.
Support notification actions. Let users respond directly from notifications — reply to messages, mark tasks complete, or snooze reminders without opening the app.
Handle delivery failures gracefully. Tokens expire when users uninstall apps or reset devices. Remove invalid tokens when push services report failures.
Respect quiet hours. Consider time zones and user preferences. A 3 AM notification about a sale won't be appreciated.