Silent push notifications for iOS
Push notifications allow you to send out notifications from your app when important events occur.
You might send a push notification when you have an important alert for a user. Push notifications can also be silent, containing no alert message or sound, being used only to update your app’s interface or trigger background work. Silent push notifications can wake your app from a “Suspended” or “Not Running” state to update content or run certain tasks without notifying your users.
Braze has several features which rely on silent push notifications:
| Feature | User Experience |
|---|---|
| Uninstall Tracking | User receives a silent, nightly uninstall tracking push. |
| Geofences | Silent syncing of geofences from server to device. |
Setting up silent push notifications
To use silent push notifications to trigger background work, you must configure your app to receive notifications even when it is in the background. To do this, add the Background Modes capability using the Signing & Capabilities pane to the main app target in Xcode. Select the Remote notifications checkbox.
Even with the remote notifications background mode enabled, the system will not launch your app into the background if the user has force-quit the application. The user must explicitly launch the application or reboot the device before the app can be automatically launched into the background by the system.
For more information, refer to pushing background updates and the application:didReceiveRemoteNotification:fetchCompletionHandler: documentation.
Sending silent push notifications
To send a silent push notification, set the content-available flag to 1 in a push notification payload.
What Apple calls a remote notification is just a normal push notification with the content-available flag set.
The content-available flag can be set in the Braze dashboard as well as within our Apple push object in the messaging API.
Attaching both a title and body with content-available=1 is not recommended because it can lead to undefined behavior. To ensure that a notification is truly silent, exclude both the title and body when setting the content-available flag to 1. For further details, refer to the official Apple documentation on background updates.
When sending a silent push notification, you might also want to include some data in the notification payload, so your application can reference the event. This could save you a few networking requests and increase the responsiveness of your app.
iOS silent notifications limitations
The iOS operating system may gate notifications for some features. Note that if you are experiencing difficulties with these features, the iOS’s silent notifications gate might be the cause.
Refer to Apple’s instance method and unreceived notifications documentation for more details.
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