是否可以将 firebase 手机身份验证减少到白名单？

Question

I want to use firebase phone authentication but I don't want to let any random phone number to login.

I know I can use "onCreate" trigger on the server and delete any new user after it is created. https://firebase.google.com/docs/functions/auth-events but this doesn't look like a clean solution.

In fact I don't even want to send the SMS code to a phone number that is not in my whitelist. (People can make mistake and enter wrong phone number) I don't want to have the whitelist on client side. it is neither secure nor private. It can be easily modified, plus all valid phone numbers can be read and harassed.

Is there a way to limit Firebase phone registration in a way that it only send the SMS if a phone number is part of a whitelist on server side. Or is there any event on Firebase server side after phone number is entered and before SMS is sent that I can use to bypass sending SMS.

Answer 1

What you're describing is unfortunately not possible with Firebase Authentication's phone auth provider. If this is a hard requirement for your project, you may have to find another provider to fit this need.

---

For many auth providers what you're describing is possible in Google Cloud Identity Platform (Firebase Authentication's paid sibling) by implementing a blocking function , but I don't see phone auth listed in the supported providers .