Auth.js v5 (NextAuth)

~22 min · Auth.js, OAuth, session

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One `auth()` works everywhere

Auth.js v5 (formerly NextAuth.js) ships a single auth() helper that runs in Server Components, Server Actions, Route Handlers, and the proxy. The mental model: "is there a session?" — same answer, same call site, no matter where you ask.

Setup

Install next-auth@beta, configure providers, export handlers + auth. Wire handlers as a Route Handler at app/api/auth/[...nextauth]/route.ts.

Where you'll call `auth()`

Location	Pattern
Server Component	`const session = await auth();`
Server Action	same
Route Handler	same
Proxy	wrap export: `export const proxy = auth(req => { … });`

Code

auth.ts — single config file·ts

// auth.ts
import NextAuth from 'next-auth';
import GitHub from 'next-auth/providers/github';
import Google from 'next-auth/providers/google';

export const { handlers, auth, signIn, signOut } = NextAuth({
  providers: [
    GitHub({ clientId: process.env.GITHUB_ID!, clientSecret: process.env.GITHUB_SECRET! }),
    Google({ clientId: process.env.GOOGLE_ID!, clientSecret: process.env.GOOGLE_SECRET! }),
  ],
});

Wire handlers, then call auth() anywhere·ts

// app/api/auth/[...nextauth]/route.ts
export { GET, POST } from '@/auth';

// In a Server Component:
import { auth } from '@/auth';
export default async function Page() {
  const session = await auth();
  return session ? <p>Welcome {session.user?.name}</p> : <SignInButton />;
}

// In a Server Action:
export async function createPost() {
  'use server';
  const session = await auth();
  if (!session) throw new Error('Unauthorized');
  // …
}

// In proxy.ts:
import { auth } from '@/auth';
import { NextResponse } from 'next/server';

export const proxy = auth((req) => {
  if (!req.auth && req.nextUrl.pathname.startsWith('/app')) {
    return NextResponse.redirect(new URL('/login', req.url));
  }
});

External links

Auth.js docs

Exercise

Set up Auth.js v5 with one OAuth provider. Add auth() calls in a Server Component, a Server Action, and the proxy. Confirm the same session is visible in all three.

Auth.js v5 (NextAuth)

One `auth()` works everywhere

Setup

Where you'll call `auth()`

Code

External links

Exercise

Progress

Comments 0

One auth() works everywhere

Setup

Where you'll call auth()

Code

External links

Exercise

Progress

One `auth()` works everywhere

Where you'll call `auth()`