explaingit

nextauthjs/next-auth

Analysis updated 2026-06-20

★ 28,224TypeScriptAudience · developerComplexity · 3/5LicenseSetup · moderate

TLDR

Auth.js is an open-source authentication library for JavaScript and TypeScript web apps that handles sign-in via OAuth providers like Google and GitHub, email magic links, and passkeys, with secure defaults baked in.

Mindmap

mindmap
  root((next-auth))
    What it does
      Handles sign-in
      OAuth providers
      Email magic links
      Passkeys
    Tech Stack
      TypeScript
      Next.js
      JWT
    Use Cases
      Add Google login
      Passwordless login
      Session management
      Database adapters
    Audience
      Web developers
      Full-stack devs
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Code map

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filefunction / class

What do people build with it?

USE CASE 1

Add Google or GitHub OAuth login to your Next.js app in minutes using pre-built provider configs.

USE CASE 2

Build a passwordless email magic-link login system without managing passwords.

USE CASE 3

Connect user authentication to an existing database using adapters for MySQL, Postgres, or MongoDB.

USE CASE 4

Implement passkey authentication for a modern password-free sign-in experience.

What is it built with?

TypeScriptNode.jsNext.jsNuxtJWTPostgreSQLMySQLMongoDB

How does it compare?

nextauthjs/next-authlinshenkx/prompt-optimizermobxjs/mobx
Stars28,22428,23328,183
LanguageTypeScriptTypeScriptTypeScript
Setup difficultymoderateeasyeasy
Complexity3/52/52/5
Audiencedevelopervibe coderdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · moderate Time to first run · 30min

Requires configuring OAuth credentials (e.g., Google API keys) or an email provider for magic links before first sign-in works.

Use freely for any purpose including commercial use, as long as you keep the copyright notice.

In plain English

Auth.js (previously called NextAuth.js) is an open-source authentication library for JavaScript web applications. Authentication is the process of verifying who a user is, think "sign in with Google" buttons, email magic links, or username/password forms. Building this securely from scratch is complex and error-prone, which is what Auth.js solves. The library supports a wide range of sign-in methods: OAuth providers like Google, GitHub, and others, email/passwordless login, and passkeys (a newer, password-free standard). You can use it with or without a database, it supports stateless sessions using JWT (JSON Web Tokens, a way to store login state without a database) as well as adapters for databases like MySQL, Postgres, MongoDB, SQLite, and more. Security defaults are baked in: CSRF (cross-site request forgery) protection on login and logout routes, encrypted tokens, restrictive cookie policies, and session sync across browser tabs. Advanced users can customize what accounts are allowed to sign in, how tokens are encoded, and how often sessions need to be re-validated. The library is runtime-agnostic, meaning it runs in Node.js, serverless environments, Docker, and more. It works with frameworks like Next.js and Nuxt. The README notes that Auth.js has joined the Better Auth project, and new projects are recommended to start with Better Auth. It's written in TypeScript and licensed under ISC (a permissive open-source license).

Copy-paste prompts

Prompt 1
Set up Auth.js in my Next.js app to let users sign in with Google OAuth. Show me the route handler and session config.
Prompt 2
Add email magic-link login to my Next.js app using Auth.js with a Postgres adapter.
Prompt 3
How do I restrict which email domains are allowed to sign in using Auth.js custom callbacks?
Prompt 4
Configure Auth.js to use JWT sessions with no database and a custom token expiry.
Prompt 5
Show me how to access the session data in a Next.js server component using Auth.js.

Frequently asked questions

What is next-auth?

Auth.js is an open-source authentication library for JavaScript and TypeScript web apps that handles sign-in via OAuth providers like Google and GitHub, email magic links, and passkeys, with secure defaults baked in.

What language is next-auth written in?

Mainly TypeScript. The stack also includes TypeScript, Node.js, Next.js.

What license does next-auth use?

Use freely for any purpose including commercial use, as long as you keep the copyright notice.

How hard is next-auth to set up?

Setup difficulty is rated moderate, with roughly 30min to a first successful run.

Who is next-auth for?

Mainly developer.

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