What problem does it solve? Setting up Firebase Authentication involves many moving parts: enabling providers, configuring authorized domains, writing client SDK code for each platform, and securing data with auth-aware security rules. This Skill guides you through the entire workflow so users can sign in securely without trial-and-error debugging. ## Core Features & Use Cases - Provider Provisioning: Enable Email/Password, Google, anonymous, and other sign-in providers via the Firebase CLI (firebase.json auth block) or the Firebase Console, then deploy with firebase deploy --only auth. - Cross-Platform Client Setup: Reference guides cover the Web JS SDK, Android (Kotlin), iOS (Swift), and Flutter, including sign-up, sign-in, sign-out, and auth state listeners. - Security Rules Integration: Use request.auth and token claims in Firestore/Storage rules to restrict data access to signed-in users or document owners. - Use Case: You are building a web app that needs Google Sign-In. The Skill walks you through enabling the provider, adding localhost to authorized domains (avoiding the common auth/unauthorized-domain popup failure), and implementing signInWithPopup with an auth state observer. ## Quick Start Set up Firebase Authentication with Google Sign-In for my web app, including provider configuration and the client sign-in code.
