Authentication Middleware with JWT
Build secure authentication into your Express app using JSON Web Tokens, and learn how to protect routes with custom auth middleware.
Why Tokens?
HTTP is stateless: the server forgets you between requests. To know who is making a request, the client sends proof of identity each time.
JSON Web Tokens (JWT) are a popular, stateless way to carry that proof without storing sessions on the server.
Anatomy of a JWT
A JWT is three Base64 sections separated by dots:
- Header: the signing algorithm
- Payload: claims like user id and role
- Signature: verifies the token was not tampered with
The payload is encoded, not encrypted — never put secrets in it.
// xxxxx.yyyyy.zzzzz
// header.payload.signatureAll lessons in this course
- Developing Custom Express Middleware
- Global Error Handling Strategies
- Input Validation with Joi/Express-Validator
- Authentication Middleware with JWT