Firebase Authentication

Status: Production Ready Last Updated: 2026-01-25 Dependencies: None (standalone skill) Latest Versions: [email protected], [email protected]

Quick Start (5 Minutes)

1. Enable Auth Providers in Firebase Console

1. Go to Firebase Console > Authentication > Sign-in method
2. Enable desired providers (Email/Password, Google, etc.)
3. Configure OAuth providers with client ID/secret

2. Initialize Firebase Auth (Client)

// src/lib/firebase.ts
import { initializeApp } from 'firebase/app';
import { getAuth } from 'firebase/auth';

const firebaseConfig = {
  apiKey: process.env.NEXT_PUBLIC_FIREBASE_API_KEY,
  authDomain: process.env.NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN,
  projectId: process.env.NEXT_PUBLIC_FIREBASE_PROJECT_ID,
  // ... other config
};

const app = initializeApp(firebaseConfig);
export const auth = getAuth(app);

3. Initialize Firebase Admin (Server)

// src/lib/firebase-admin.ts
import { initializeApp, cert, getApps } from 'firebase-admin/app';
import { getAuth } from 'firebase-admin/auth';

if (!getApps().length) {
  initializeApp({
    credential: cert({
      projectId: process.env.FIREBASE_PROJECT_ID,
      clientEmail: process.env.FIREBASE_CLIENT_EMAIL,
      privateKey: process.env.FIREBASE_PRIVATE_KEY?.replace(/\\n/g, '\n'),
    }),
  });
}

export const adminAuth = getAuth();

Email/Password Authentication

Sign Up

import { createUserWithEmailAndPassword, sendEmailVerification, updateProfile } from 'firebase/auth';
import { auth } from './firebase';

async function signUp(email: string, password: string, displayName: string) {
  try {
    const userCredential = await createUserWithEmailAndPassword(auth, email, password);
    const user = userCredential.user;

    // Update display name
    await updateProfile(user, { displayName });

    // Send verification email
    await sendEmailVerification(user);

    return user;
  } catch (error: any) {
    switch (error.code) {
      case 'auth/email-already-in-use':
        throw new Error('Email already registered');
      case 'auth/invalid-email':
        throw new Error('Invalid email address');
      case 'auth/weak-password':
        throw new Error('Password must be at least 6 characters');
      default:
        throw new Error('Sign up failed');
    }
  }
}

Sign In

import { signInWithEmailAndPassword } from 'firebase/auth';
import { auth } from './firebase';

async function signIn(email: string, password: string) {
  try {
    const userCredential = await signInWithEmailAndPassword(auth, email, password);
    return userCredential.user;
  } catch (error: any) {
    switch (error.code) {
      case 'auth/user-not-found':
      case 'auth/wrong-password':
      case 'auth/invalid-credential':
        throw new Error('Invalid email or password');
      case 'auth/user-disabled':
        throw new Error('Account has been disabled');
      case 'auth/too-many-requests':
        throw new Error('Too many attempts. Try again later.');
      default:
        throw new Error('Sign in failed');
    }
  }
}

Sign Out

import { signOut } from 'firebase/auth';
import { auth } from './firebase';

async function handleSignOut() {
  await signOut(auth);
  // Redirect to login page
}

Password Reset

import { sendPasswordResetEmail, confirmPasswordReset } from 'firebase/auth';
import { auth } from './firebase';

// Send reset email
async function resetPassword(email: string) {
  await sendPasswordResetEmail(auth, email);
}

// Confirm reset (from email link)
async function confirmReset(oobCode: string, newPassword: string) {
  await confirmPasswordReset(auth, oobCode, newPassword);
}

OAuth Providers (Google, GitHub, etc.)

Google Sign-In

import { signInWithPopup, signInWithRedirect, GoogleAuthProvider } from 'firebase/auth';
import { auth } from './firebase';

const googleProvider = new GoogleAuthProvider();
googleProvider.addScope('email');
googlePro