What is a JWT?
A JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.
JWTs are commonly used for authentication and authorization in modern web applications (e.g., Bearer tokens in API requests).
Token Structure
A JWT consists of three parts separated by dots (.):
- Header: Contains the token type (JWT) and the signing algorithm being used (e.g., HS256 or RS256).
- Payload: Contains the claims. Claims are statements about an entity (typically, the user) and additional data (like expiration times).
- Signature: Used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn’t changed along the way.
Secure Local Generation
Our tool uses the native Web Crypto API to sign your token directly inside your browser. Your secret key and payload are never transmitted to any server, ensuring 100% privacy when generating test tokens for your applications.