All 5 Authentication & Authorization in Next.js questions
More in Authentication & Authorization in Next.js
What is the difference between authentication and authorization in a Next.js application? How would you protect a page in the App Router so only logged in users can access it? How can you use middleware to protect multiple routes at once for authentication? How do you implement role based authorization, where different users see different content based on their role?
Advertisement
Next.js › Authentication & Authorization in Next.js

What are best practices for securely storing and validating authentication tokens in a Next.js app?

Advanced

Answer

Store authentication tokens in secure, httpOnly cookies so they cannot be accessed by client side JavaScript, always use HTTPS in production, set a reasonable expiration time, and verify token signatures on the server for every protected request rather than trusting client provided data.
res.setHeader('Set-Cookie', `session=${token}; HttpOnly; Secure; SameSite=Lax; Path=/`);
Real-world example A banking application stores its session token in an httpOnly secure cookie, preventing malicious scripts from stealing the token even if they somehow get injected into the page.

Common follow-ups: What is the difference between storing a token in a cookie versus local storage?;How often should authentication tokens be refreshed or rotated?

Security Best Practices in Next.js;Cookies & Session Management in Next.js
All 5 Authentication & Authorization in Next.js questions