CODEWITHSUNDEEP
firebasefirebase-cloud-messaging
Rajeev
Rajeev

Reputation: 494

How a Firebase token is generated?

I'm doing analysis on Firebase Token and understood below points:-

-> A Firebase token is saved in database which will be used for sending notifications.

-> The token generally do not expire except in the following cases:

- The app deletes Instance ID
- The app is restored on a new device
- The user uninstalls/reinstall the app
- The user clears app data.

-> When we use a token which is expired we get errors like Not Registered from the response while sending messages.

-> To avoid the error, we should be deleting the token from database.

  1. So, the token is generated based on browser or System IP or what exactly the Fcm uses to generate a token ?

Upvotes: 0

Views: 255

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317427

The method used to generate the token is an implementation detail, and you should not depend on that to build your app.

A token uniquely identifies a device. Each device receives messages independently of each other, and does not know anything about the user of that device. It's expected that if a user signed into an app on multiple devices, that each device would generate a unique token. If you want to send message to a user, you will have to map each of the user's device tokens in your own database, and send the message to each of them, or only the ones that the user chooses.

You can expect that device tokens might change over time. If you send a message to a device, and the API tells you that the token is not valid, you should simply delete it from your records.

Upvotes: 2

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