Firebase token error, “The custom token corresponds to a different audience.”

Question

I'm trying to generate JWT token for Firebase using Ruby on the server. Before 3.0 we used token generator but it stopped working after the upgrade. The token I get with code below gives an error:

The custom token corresponds to a different audience.

and I can't find anywhere what it means.

private_key = OpenSSL::PKey::RSA.new <<-PEM
-----BEGIN PRIVATE KEY-----
..redacted..
-----END PRIVATE KEY-----
PEM

service_account_email = '[email protected]'
now_seconds = Time.now.to_i

payload = {
  iss: service_account_email,
  sub: service_account_email,
  aud: 'https://identitytoolkit.googleapis.com/google.identity.identitytoolkit.v1.IdentityToolkit',
  iat: now_seconds,
  exp: now_seconds + (60 * 60),
  uid: self.id.to_s,
  debug: true,
  claims: {
    userId: self.id,
    slug: self.slug,
    username: self.username,
    avatar: self.profile.avatar.url,
    group: self.group,
    debug: true
  }
}

JWT.encode payload, private_key, 'RS256'

Thanks

Rahav Lussato Rahav Lussato · Accepted Answer · 2016-08-17T11:39:20

I got this error too, I got that because I used a service account that was not related to the firebase project. After creating new service account with new key under the firebase project its started to work.

For creating service account you can follow the instructions here : https://firebase.google.com/docs/server/setup

Firebase token error, “The custom token corresponds to a different audience.”

3 Answers