Implementing robust authentication is crucial for modern web applications. This guide walks through securing Next.js 14 applications using Auth.js (formerly NextAuth.js) with industry-best practices.

Why Authentication Matters

With 80% of breaches involving credential abuse (Verizon DBIR 2023), proper auth implementation is your first defense line.

Security Note: Never store plaintext passwords. Always use hashing (bcrypt, Argon2).

Auth.js Setup in Next.js 14

Installation 
npm install @auth/core @auth/nextjs

Configuration

1. Environment Variables

# .env.local
AUTH_SECRET=your-random-secret
GITHUB_ID=your-client-id
GITHUB_SECRET=your-client-secret

2. Auth Config

// auth.config.ts
import type { NextAuthConfig } from "next-auth"

export const authConfig = {
  providers: [],
  pages: {
    signIn: "/login"
  }
} satisfies NextAuthConfig

Security Best Practices

1

Use Middleware

Protect routes with Next.js middleware

2

Enable CSRF Protection

Auth.js includes this by default

3

Implement Rate Limiting

Prevent brute force attacks

Middleware Example

// middleware.ts
import { authConfig } from "./auth.config"
import NextAuth from "next-auth"

export default NextAuth(authConfig).auth

export const config = {
  matcher: ["/((?!api|_next/static|_next/image|.+\\.png$).*)"]
}

OAuth Providers

Auth.js supports all major providers:

GitHub
Google
Microsoft
Facebook
Pro Tip: For production apps, consider using Passkey authentication for better security and UX.