How to check if a user is already registered in Firebase Authentication

Question

I am using firebase authentication for application registration. If someone who registered for the application wants to register again, I want to give a warning that this mail is being used, how can I handle it?

Answer 1

Which platform do you implement... and firebase has various platform samples with all the features. The firebase GitHub page is here .it's hard to find you needed one try this

Answer 2

To check whether a given email address is already registered in Firebase, you can call the fetchSignInMethodsForEmail methods .

The flow for this is typically that:

1. You ask/determine the email address of the user.
2. You call fetchSignInMethodsForEmail to see if there's any provider for the email address.
3. You show a page where the user can pick from the methods that you got back in step 2.