Express 5 Authentication Middleware (JWT Protect)
Middleware in Express runs between the incoming request and the controller. In an authentication system, middleware verifies JWT tokens before allowing access to protected routes. This guide extends the Register and Login APIs and includes environment variable setup and cookie parsing required for secure token handling.
Auth Routes With Middleware Placement
Demonstrates public and protected routes. Authentication middleware runs before controllers for secured endpoints.
Authentication Request Flow
High-level flow showing how cookies, headers, middleware, and controllers work together.
Auth Module Folder Structure (With Middleware)
Shows where authentication middleware, environment configuration, and server setup live in a real-world backend project.
Install cookie-parser
cookie-parser is required to read JWT tokens from HTTP-only cookies. Without this middleware, req.cookies will be undefined.
Environment Variables
Environment variables store sensitive values like database URLs and JWT secrets. Never commit this file to GitHub. Add it to .gitignore.
Enable cookie-parser in Server
Registers cookie-parser middleware so authentication middleware can access JWT tokens stored in cookies.
JWT Authentication Middleware (Cookie or Header)
This authentication middleware secures protected routes by validating a JSON Web Token (JWT) sent either via HTTP-only cookies or the Authorization header. It supports browser-based authentication and API clients. If the token is valid, the decoded user ID is attached to the request object and the request continues to the controller.
Related Documents
Express 5 User Register API (Production Ready)
Step-by-step guide to build a secure user registration API using Express 5 (Node.js 22 LTS) and MongoDB. This documentation focuses on real-world project structure: full server setup, proper folder organization, schema design, request validation, password hashing, duplicate user prevention, JWT token generation, and clean error handling. Ideal for beginners who want production-quality code, not just theory.