Handling FCM Tokens for Multiple Accounts on the Same Device

When implementing Firebase Cloud Messaging (FCM) in an Android application, it is crucial to understand the behaviour of FCM tokens in relation to multiple user accounts registered on the same device.

FCM tokens are associated with device instances, not user accounts. This means that a single device can have multiple FCM tokens if multiple users are logged into different accounts on the device.

To handle this scenario effectively, consider the following guidelines:

• Store Tokens Against User Accounts: Store the FCM token in the database for each user account, not just the device. This allows you to target specific users with notifications even if they are using the same device.
• Handle Account Switching: When a user logs out of their account and logs into another account, remove the old FCM token mapping from the database and create a new mapping with the same token for the new account.
• Uninstallation and Reinstallation: If the app is uninstalled and reinstalled on the device, a new FCM token will be generated. In this case, update the FCM token mapping for all user accounts that are using that device.

By following these guidelines, you can effectively manage FCM tokens for multiple user accounts on the same device.