Enhancing Authentication Security with Cookies in Next.js and Express.js

I recently worked on a project where I implemented custom authentication using Express.js for the backend and Next.js for the frontend. Initially, I stored authentication tokens in both localStorage and cookies, but I realized this approach had security limitations—localStorage is vulnerable to XSS attacks, and token management can be inconsistent.

To improve security and streamline authentication, I transitioned to a fully cookie-based authentication system. Here’s what I learned and how I implemented it:

Next.js Middleware for Route Protection and Role-Based Access

• Middleware intercepts requests and extracts authentication data from the cookie.
• It ensures protected routes are only accessible to authenticated users.
• Role-based access control is dynamically enforced based on user roles.

Axios Instance for Secure API Calls

• A custom Axios instance automatically includes the authentication cookie in every request.
• This eliminates the need to manually attach tokens, ensuring seamless authentication.

Secure Token Storage & Logout

• After login, the backend issues an HTTP-only, secure cookie to store the authentication token.
• On logout, a dedicated API clears the cookie, ensuring a proper session termination.

Why Choose Cookie-Based Authentication?

✅ Better Security – Protects against XSS & CSRF attacks with HTTP-only and SameSite cookies.

✅ Automatic Token Handling – No need to manually send tokens in API requests.

✅ Seamless Route Protection – Middleware efficiently manages access control.

✅ Cleaner Logout Process – Server-side cookie management ensures proper session clearing.

This approach has significantly improved both security and maintainability in my authentication workflow. I’d love to hear how others handle authentication—what’s your approach?