Firebase change authentication type email to phone

Question

I developed a ionic 5 angular based mobile app that uses firebase authentication. I currently use email based login and now i want to switch to phone number based one. Is there any option to verify all the already registered users's phone number using firebase or any other service?

Answer 1

There is no way to change the authentication type of an existing account. But what you can do is also allow the user to sign in with their phone number, and then link the phone number credentials to their existing account.

For full details on how to do this, see the Firebase documentation on linking multiple auth providers to an account.