What is a JWT?
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.
JWT Structure
A JWT is a string comprising three Base64URL-encoded parts: the Header (Algorithm & Token Type), the Payload (Data/Claims), and the Signature. These parts are concatenated with a dot (.) separator:
header.payload.signature
Common Use Cases
- Authorization: The most common scenario. Once the user is logged in, each subsequent request will include the JWT, allowing the user to access routes, services, and resources.
- Information Exchange: JWTs are checking valid credentials between parties.
- Stateless Sessions: No need to keep session data on the server; the token contains all necessary user info.
Privacy & Security
Your security is our priority. All JWT decoding and verification logic happens client-side in your browser JavaScript. No tokens, headers, or payloads are ever sent to our servers.
100% Browser-Based