JWT
A compact, cryptographically signed token used to securely transmit information (like user identity and permissions) between a client and a server.
What it is
When a user logs in, the server generates a JWT containing their user ID and digitally signs it. The client stores this token and attaches it to all future API requests. Because the token is signed, the server can instantly verify the user's identity mathematically without needing to query the database every time.
When you would use it
You use JWTs when architecting modern, stateless authentication systems where frontend applications must repeatedly prove their identity to backend APIs efficiently.
Common operations
- Maintaining user authentication state in stateless REST APIs.
- Passing secure authorization headers from a React frontend to a backend microservice.