Firebase Docs Reference Interface: AuthCredential firebase.auth.AuthCredential interface static Interface that represents the credentials returned by an auth provider. Implementations specify the details about each auth provider's credential requirements. Property providerId string The authentication provider ID for the credential. For example, 'facebook.com', or 'google.com'. Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated May 17, 2017.