Create the Auth.js configuration and export its generated methods.
Application initialization
Auth.js · Function
NextAuth
NextAuth initializes Auth.js for a Next.js application from a NextAuthConfig and returns integration methods. Its result includes universal authentication access and route handlers.
How it works
Calling NextAuth with an authentication configuration initializes Auth.js for a Next.js application and returns framework integration methods. The returned auth method can be used across Middleware, Server Components, Route Handlers, and API Routes, while handlers connect the authentication endpoints.
Syntax
NextAuth(config)Parameters
| Name | Type | Description |
|---|---|---|
config | NextAuthConfig | Authentication configuration containing providers and other Auth.js options. |
Returns
A NextAuthResult containing methods such as auth and handlers for setting up and interacting with Auth.js in a Next.js application.
Key points
- NextAuth is the Auth.js integration intended specifically for Next.js applications.
- The function accepts a NextAuthConfig and produces a result object for application integration.
- The returned auth method provides one server-side entry point for authentication operations.
- Export auth from the configuration file so it can be imported by middleware and server-side code.
- The universal auth method supports both App Router route handlers and Pages Router API routes.
Common mistakes
- Keep the configuration in auth.ts before using the returned auth method throughout the application.
- NextAuth returns an object of methods; export only the methods your application needs.
Example: Initialize Auth.js with GitHub
import NextAuth from "next-auth"
import GitHub from "next-auth/providers/github"
export const { handlers, auth } = NextAuth({
providers: [GitHub],
})Create the Auth.js configuration and export the generated handlers and universal auth method.
When to use it
Call the returned auth method from Middleware, Server Components, or route handlers.
Server-side authentication
Use the returned handlers to connect Auth.js endpoints to the Next.js routing system.
Authentication endpoints
Interview questions
QWhat does calling NextAuth do?
NextAuth initializes Auth.js from a NextAuthConfig and returns a NextAuthResult. That result provides integration methods such as auth and handlers for use in a Next.js application.
Follow-up: How would you use the returned auth method? Use it in Middleware, Server Components, Route Handlers, or API Routes to interact with authentication.
QWhere can the returned auth method be used?
The auth method is a universal method returned by NextAuth. After configuration, it can be used in Middleware, Server Components, Route Handlers under app/, and Edge or Node.js API Routes.
Follow-up: Why is this useful? A single exported method replaces framework-location-specific server authentication access patterns.
QWhat are handlers and providers used for?
The handlers returned by NextAuth are used to set up the authentication route handlers in a Next.js application. The configuration also accepts providers, which define available authentication integrations.
Follow-up: What must be configured for a provider-based login? Add the provider to the providers array passed to NextAuth.
Related
NextAuthResultauthhandlersNextAuthConfigproviders