JWT Decoder

Paste a JWT token to decode its header, payload, and signature. Everything runs in your browser — nothing is sent to the server.

What is a JWT?

JSON Web Token (JWT) is a compact, URL-safe token format used for securely transmitting information between parties as a JSON object.

A JWT consists of three parts separated by dots: Header (algorithm and token type), Payload (claims/data), and Signature (verification).

This tool decodes the header and payload locally in your browser. It does not verify the signature — that requires the signing key.