For users on Android Oreo and above, users will get a badge icon automatically, and it will match the number of notifications currently in the tray. You may want to consider some kind of behavior where your app dismisses open notifications automatically when you enter the app to keep this number clearing out as messages are read. I outlined how we handle it previously: How to handle push notifications in both client end and server end? - #15 by ahmedsamyabdelhay