Get unsigned token for user from firebase auth emulator without frontend

Question

I am writing a custom backend (nestjs) in which I want to verify if the token from firebase auth is valid and retrieve user information too.

I do not want to use the actual firebase auth so I ended up using firebase local emulator.

Now I want to test my endpoint written in nestjs using postman wherein I send the unsigned token from postman for nestjs to verify from local emulator. But I couldn't find a way to create an unsigned token without creating a UI for the same, I really do not want to spend time in creating a react application to just console.log a token. Is there any better way to do this that I might be missing ??

Thanks for the help.

Answer 1

Assuming your Authentication emulator runs on port 9099 and you have a user created, you should be able to make the following HTTP POST request to get a token. The token is in the idToken field of the response object.

http://localhost:9099/identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key=any_key_you_want

Body (JSON):

{
  "email": "your-user@mail.com",
  "password": "some-password"   
}

Response:

{
    "kind": "identitytoolkit#VerifyPasswordResponse",
    "registered": true,
    "localId": "yourUserId",
    "email": "your-user@mail.com",
    "idToken": "someIdToken",
    "refreshToken": "someRefreshToken",
    "expiresIn": "3600"
}

I found this solution playing with a React application with the firebase (^9.6.2) package installed, setting connectAuthEmulator(auth, "http://localhost:9099");, and looking at the request it made when I logged in.