Decode JSON Web Tokens (JWT) instantly in your browser. View the header, payload, and check token expiration. No server uploads — your tokens stay private.
Paste a JWT token (like those from Auth0, Firebase, or custom auth). The token format is header.payload.signature, separated by dots.
Yes — all decoding happens in your browser using JavaScript. Your token is never sent to any server. However, never share tokens containing sensitive data.
A JWT has three parts: Header (algorithm), Payload (claims like user ID, expiry), and Signature (cryptographic verification). Our decoder shows the first two in readable format.