I’m developing a custom MFA-based authentication system, so I prefer not to use the Firebase client SDK since Firebase only supports MFA via SMS, not email.

I’m building my own system, but I’m surprised there’s no built-in method to refresh an expired access token with a refresh token. I understand this is typically handled by the Client SDK, but I don’t see why it couldn’t be included in Firebase Admin.

I know there are third-party solutions, like Pyrebase, but these still rely on external libraries, and it’s essentially just a Google API request. It’s a relatively simple feature... Let me know if this is feasible, or if necessary, I could develop this feature and submit a PR.