Firebase gives you complete control over authentication by allowing you to authenticate users or devices using secure JSON Web Tokens (JWTs) . You generate these tokens on your server, pass them back to a client device, and then use them to authenticate via the signInWithCustomToken() method.
Read moreDoes Firebase authentication use OAuth2?
You need to have the user go through the OAuth 2.0 auth code flow and grant access to your app. … This token will allow the user to sign-in into Firebase in our web app using the signInWithCustomToken method.
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