JWT Decoder
Decode and inspect JSON Web Tokens (JWT) payload, header, and signature client-side.
What is a JSON Web Token (JWT)?
A JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact, self-contained way for securely transmitting information between parties as a JSON object. JWTs are widely used for user authentication and authorization in modern APIs and single-sign-on (SSO) systems. A JWT is represented as a string consisting of three parts separated by dots (.): the Header, the Payload, and the Signature.
How it Works
Our JWT Decoder takes your token, splits it by the dot separator, and decodes the three distinct components:
- Header: Typically contains the token type (JWT) and the signing algorithm used (e.g., HS256, RS256).
- Payload (Claims): Contains the claims or statements about the user and additional data (such as user ID, role, issue time, and expiration time).
- Signature: The cryptographic signature used by the server to verify the integrity and authenticity of the token.
exp (expiration) and iat (issued at) to show you the token status in plain, readable local date/time.
Privacy and Signature Verification
Since this decoder runs entirely client-side, your token remains in your browser and is never sent to any server. This tool performs decoding only and does not verify the signature (which would require you to share the private secret key, a practice we discourage for web-based tools).
Frequently Asked Questions
No. This is a decode-only tool. It parses and formats the JWT header and payload claims into human-readable JSON. Verification of the signature requires a secret or public key, which you should never share with a public online tool.
Yes. Since decoding is processed client-side inside your browser, the token is never transmitted to our server or any third party. Your authentication tokens remain completely private.
If the JWT contains an "exp" (expiration time) claim in its payload, our decoder automatically parses it and displays a badge showing if the token is Active or Expired, along with the exact expiration date and time in your local timezone.
The color coding matches standard JWT debuggers: red represents the token Header (metadata & algorithm), purple represents the Payload (user claims and scopes), and blue represents the Signature block.
Our decoder can parse any standard JSON Web Token, regardless of the signing algorithm (e.g. HS256, RS256, ES256). As long as it consists of three Base64URL encoded segments separated by dots, it will decode normally.