How to verify FCM registration token on server?

Question

I got my Firebase Cloud Messaging registration token for web push. And I sent this to my server to save in database for later push. But how can I verify this token is valid

Answer 1

One way is to send a message with the dry_run option = true, as is described by AL. in the other answer.

Another way is to use the InstanceId server API:
https://developers.google.com/instance-id/reference/server