For the followers feature in the future the backend needs to be able to use a phone number from a users contacts to fetch userIds. We store the users phone number with Firebase Authentication. It seems the userId across the backend and Firebase is the same so assuming we can fetch users from Firebase using their phone number it should then be simple to do the rest in the backend with the findUserByIdOrFail function.
For the followers feature in the future the backend needs to be able to use a phone number from a users contacts to fetch userIds. We store the users phone number with Firebase Authentication. It seems the userId across the backend and Firebase is the same so assuming we can fetch users from Firebase using their phone number it should then be simple to do the rest in the backend with the
findUserByIdOrFailfunction.