Decode and inspect JSON Web Tokens. View header, payload, and verify structure — all client-side.
A JSON Web Token is a compact, URL-safe token format used for securely transmitting information between parties as a JSON object.
This tool decodes and displays the header and payload. Signature verification requires the secret key, which should never be shared in a browser tool.
Yes — everything runs in your browser. No data is sent to any server.
A JWT has three Base64-encoded parts separated by dots: the header (algorithm and type), the payload (claims), and the signature.