Firebase SignIn Using a Token from REST API

Question

I have whole project using Firebase REST API but I want start using Firebase SDKs (iOS/Android) without stop using Authentication REST API. I have access to this tokens:

• access_token
• id_token
• refresh_token

Can I use them to log into Firebase Authentication SDKs iOS or/and Android? If yes, how?

Regards

Answer 1

These are only applicable through the rest API as you will have to authenticate within the module to invoke the user auth process.

To break it down, the access_token and id_token as interchangeable, the refresh token allows the client to request new a id_token when it expires or invoked manually. But to my knowledge, there is no way to manually inject a refresh token into the auth state and would require something like the admin-sdk to create a custom auth token for cross-platform authentication.

In that situation, I would recommend a cloud function and using the custom auth to validate the user to migrate from the rest API to the firebase modules.

All you need to do is create a Cloud Function that on invoke, gets the users current Auth.uid (would be done with your provided id_token ) - With the users uid , you can create a custom sign-in token that being said, you can also sign in with a 3rd party JWT, but this is not recommended.