JWT Decoder
Decode and inspect JSON Web Tokens (JWT) instantly in your browser without sending them to a server.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) instantly in your browser without sending them to a server.
About JWT decoding
Parse the three token parts
The decoder expects the standard header.payload.signature shape. It Base64URL-decodes the header and payload JSON, shows the algorithm when present, and converts exp into local time with an active or expired label.
Format valid is not signature verified
The signature segment is displayed as text, but no secret, public key, issuer policy, or audience check is applied. A valid status means the token can be parsed, not that it should be trusted for login, authorization, or production debugging.
FAQ
Common questions and answers about this topic.
What is a JWT?
A JWT (JSON Web Token) is a compact, URL-safe token format used for securely transmitting information between parties as a JSON object.
What parts of a JWT are decoded?
The header and payload are decoded and displayed as formatted JSON. The signature segment is separated as text, and the page also shows expiration status and algorithm information when those claims exist.
Can this verify JWT signatures?
This tool decodes and displays the token contents. Signature verification requires the secret key and is not performed client-side for security reasons.
Is my data sent to any server?
No, JWT decoding happens entirely in your browser. Your token is decoded locally with JavaScript — the token content is never sent to any server.