Firebase authentication Login multiple provider with same email

Question

I want users can login using many different provider Like Google+, Facebook and Email/Password but they will get same result if they use only same email address. Prevent multiple accounts and data managed by same UID

Answer 1

That is actually a feature of Firebase Authentication. If you configure it to allow only one account per email address (which is the default I think), it will only allow a single account per email address. When a user then logs in with a different provider, you can link the credentials for both under a single account/UID.