How JWT Authentication Works

JWT (JSON Web Token) is a popular authentication mechanism used in modern web applications to securely transmit information between client and server.

What Is JWT?

A JWT is a compact, URL-safe token that contains user information and is digitally signed.

Structure of JWT

• Header
• Payload
• Signature

Authentication Flow

When a user logs in, the server verifies credentials and generates a JWT token.

{ "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9" }

Using JWT on Client Side

The client stores the token and sends it with each request in the Authorization header.

Authorization: Bearer YOUR_JWT_TOKEN

Token Verification

The server validates the token signature before granting access to protected routes.

Advantages of JWT

• Stateless authentication
• Scalable
• Secure when implemented correctly

Conclusion

JWT authentication is widely used due to its simplicity and scalability. Understanding its flow is essential for backend developers.