I'm new to Firebase and I was wondering if the following is possible: I would like to be able to authenticate on a new device using a 4 or 6 digit pin code. Basically a quick way to add a device that is logged in. From what I can see from the docs this is not a built-in functionality, but maybe someone has created something like this.
Thanks!
As you've already discovered, signing in with only a PIN-code/password is not a built-in authentication method for Firebase. If you want to allow something like this in your app, you can build a custom auth provider for it.
If you're targeting iOS, the Firebase SDKs have the ability to synchronize a user's login state across all Apple user's devices, which accomplishes a similar use-case without requiring a separate PIN
