merge two uids in firebase authentication in flutter application

Question

I am able to successfully Authenticate Through Facebook and Phone Authentication separately in firebase authentication for the flutter application.

I have question if the User is already authenticated through Facebook or Phone Number and if the user wants to add his phone number to the Facebook Authentication record or Facebook Authentication to the phone number authentication record, means merging these two and maintaining both the Single uid for the User in firebase auth, how can this be possible?

Answer 1

What you're describing is possible in Firebase Authentication by linking the user's credentials from those auth providers together. It is documented under account linking, and while that page is for Android, the same logic is available on Flutter under linkWithCredential and linkWithPhoneNumber.