--- name: auth0-nextjs description: Use when adding authentication to Next.js applications with both server and client-side auth - supports App Router and Pages Router with @auth0/nextjs-auth0 SDK --- # Auth0 Next.js Integration Add authentication to Next.js applications using @auth0/nextjs-auth0. Supports both App Router and Pages Router. --- ## Prerequisites - Next.js 13+ application (App Router or Pages Router) - Auth0 account and application configured - If you don't have Auth0 set up yet, use the `auth0-quickstart` skill first ## When NOT to Use - **Client-side only React apps** - Use `auth0-react` for Vite/CRA SPAs - **React Native mobile apps** - Use `auth0-react-native` for iOS/Android - **Non-Next.js frameworks** - Use framework-specific SDKs (Express, Vue, Angular, etc.) - **Stateless APIs only** - Use JWT validation middleware if you don't need session management --- ## Quick Start Workflow ### 1. Install SDK ```bash npm install @auth0/nextjs-auth0 ``` ### 2. Configure Environment **For automated setup with Auth0 CLI**, see [Setup Guide](references/setup.md) for complete scripts. **For manual setup:** Create `.env.local`: ```bash AUTH0_SECRET= APP_BASE_URL=http://localhost:3000 AUTH0_DOMAIN=your-tenant.auth0.com AUTH0_CLIENT_ID=your-client-id AUTH0_CLIENT_SECRET=your-client-secret ``` Generate secret: `openssl rand -hex 32` **Important:** Add `.env.local` to `.gitignore` ### 3. Create Auth0 Client and Middleware Create `lib/auth0.ts`: ```typescript import { Auth0Client } from '@auth0/nextjs-auth0/server'; export const auth0 = new Auth0Client({ domain: process.env.AUTH0_DOMAIN!, clientId: process.env.AUTH0_CLIENT_ID!, clientSecret: process.env.AUTH0_CLIENT_SECRET!, secret: process.env.AUTH0_SECRET!, appBaseUrl: process.env.APP_BASE_URL!, }); ``` **Middleware Configuration (Next.js 15 vs 16):** **Next.js 15** - Create `middleware.ts` at project root: ```typescript import { NextRequest } from 'next/server'; import { auth0 } from './lib/auth0'; export async function middleware(request: NextRequest) { return await auth0.middleware(request); } export const config = { matcher: [ '/((?!_next/static|_next/image|favicon.ico|sitemap.xml|robots.txt).*)', ], }; ``` **Next.js 16** - You have two options: **Option 1:** Use `middleware.ts` (same as Next.js 15): ```typescript import { NextRequest } from 'next/server'; import { auth0 } from './lib/auth0'; export async function middleware(request: NextRequest) { return await auth0.middleware(request); } export const config = { matcher: [ '/((?!_next/static|_next/image|favicon.ico|sitemap.xml|robots.txt).*)', ], }; ``` **Option 2:** Use `proxy.ts` at project root: ```typescript import { NextRequest } from 'next/server'; import { auth0 } from './lib/auth0'; export async function proxy(request: NextRequest) { return await auth0.middleware(request); } export const config = { matcher: [ '/((?!_next/static|_next/image|favicon.ico|sitemap.xml|robots.txt).*)', ], }; ``` This automatically creates endpoints: - `/auth/login` - Login - `/auth/logout` - Logout - `/auth/callback` - OAuth callback - `/auth/profile` - User profile ### 4. Add User Context (Optional) **Note:** In v4, wrapping with `` is optional. Only needed if you want to pass an initial user during server rendering to `useUser()`. **App Router** - Optionally wrap app in `app/layout.tsx`: ```typescript import { Auth0Provider } from '@auth0/nextjs-auth0/client'; import { auth0 } from './lib/auth0'; export default async function RootLayout({ children }: { children: React.ReactNode }) { const session = await auth0.getSession(); return ( {children} ); } ``` **Pages Router** - Optionally wrap app in `pages/_app.tsx`: ```typescript import { Auth0Provider } from '@auth0/nextjs-auth0/client'; import type { AppProps } from 'next/app'; export default function App({ Component, pageProps }: AppProps) { return ( ); } ``` ### 5. Add Authentication UI **Client Component** (works in both routers): ```typescript 'use client'; // Only needed for App Router import { useUser } from '@auth0/nextjs-auth0/client'; export default function Profile() { const { user, isLoading } = useUser(); if (isLoading) return

; if (user) { return (

Welcome, {user.name}!

Logout

); } return Login; } ``` ### 6. Test Authentication Start your dev server: ```bash npm run dev ``` Visit `http://localhost:3000` and test the login flow. --- ## Detailed Documentation - **[Setup Guide](references/setup.md)** - Automated setup scripts, environment configuration, Auth0 CLI usage - **[Integration Guide](references/integration.md)** - Server-side auth, protected routes, API routes, middleware - **[API Reference](references/api.md)** - Complete SDK API, hooks, helpers, session management --- ## Common Mistakes | Mistake | Fix | |---------|-----| | Using v3 environment variables | v4 uses `APP_BASE_URL` and `AUTH0_DOMAIN` (not `AUTH0_BASE_URL` or `AUTH0_ISSUER_BASE_URL`) | | Forgot to add callback URL in Auth0 Dashboard | Add `/auth/callback` to Allowed Callback URLs (e.g., `http://localhost:3000/auth/callback`) | | Missing middleware configuration | v4 requires middleware to mount auth routes - create `middleware.ts` (Next.js 15+16) or `proxy.ts` (Next.js 16 only) with `auth0.middleware()` | | Wrong route paths | v4 uses `/auth/login` not `/api/auth/login` - routes drop the `/api` prefix | | Missing or weak AUTH0_SECRET | Generate secure secret with `openssl rand -hex 32` and store in .env.local | | Using .env instead of .env.local | Next.js requires .env.local for local secrets, and .env.local should be in .gitignore | | App created as SPA type in Auth0 | Must be Regular Web Application type for Next.js | | Using removed v3 helpers | v4 removed `withPageAuthRequired` and `withApiAuthRequired` - use `getSession()` instead | | Using useUser in Server Component | useUser is client-only, use `auth0.getSession()` for Server Components | | AUTH0_DOMAIN includes https:// | v4 `AUTH0_DOMAIN` should be just the domain (e.g., `example.auth0.com`), no scheme | --- ## Related Skills - `auth0-quickstart` - Basic Auth0 setup - `auth0-migration` - Migrate from another auth provider - `auth0-mfa` - Add Multi-Factor Authentication --- ## Quick Reference **V4 Setup:** - Create `lib/auth0.ts` with `Auth0Client` instance - Create middleware configuration (required): - Next.js 15: `middleware.ts` with `middleware()` function - Next.js 16: `middleware.ts` with `middleware()` OR `proxy.ts` with `proxy()` function - Optional: Wrap with `` for SSR user **Client-Side Hooks:** - `useUser()` - Get user in client components - `user` - User profile object - `isLoading` - Loading state **Server-Side Methods:** - `auth0.getSession()` - Get session in Server Components/API routes/middleware - `auth0.getAccessToken()` - Get access token for calling APIs **Common Use Cases:** - Login/Logout links → Use `/auth/login` and `/auth/logout` paths (see Step 5) - Protected pages (App Router) → [Integration Guide](references/integration.md#protected-pages-app-router) - Protected pages (Pages Router) → [Integration Guide](references/integration.md#protected-pages-pages-router) - API routes with auth → [Integration Guide](references/integration.md#protected-api-routes) - Middleware protection → [Integration Guide](references/integration.md#middleware) --- ## References - [Auth0 Next.js SDK Documentation](https://auth0.com/docs/libraries/nextjs) - [Auth0 Next.js Quickstart](https://auth0.com/docs/quickstart/webapp/nextjs) - [SDK GitHub Repository](https://github.com/auth0/nextjs-auth0)