How do I use Firebase messaging service?

Firebase Notifications is a free service that enables user notifications for Android and iOS devices . Through the Firebase console, you can send notifications quickly and easily across platforms with no server coding required.

Public Method Summary voidonDeletedMessages() Called when the Firebase Cloud Messaging server deletes pending messages.voidonNewToken(String token) Called when a new token for the default Firebase project is generated.FirebaseMessagingService – Google firebase.google.com › docs › android › com › google › firebase › messaging

Firebase Instance ID provides a unique identifier for each app instance and a mechanism to authenticate and authorize actions (example: sending FCM messages). Instance ID is stable except when: App deletes Instance ID. App is restored on a new device. User uninstalls/reinstall the app.

Set up a Firebase Cloud Messaging client app on Android