JWT Decoder
Safely decode JSON Web Tokens (JWT) to inspect their header and payload claims locally.
Awaiting valid JWT...
Runs locally in your browser. 100% private & secure.
About JWT Decoder
What is a JWT?
JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.
The Anatomy of a JWT
A JWT string is separated by dots (.) into three parts:
- Header: Contains the token type and the hashing algorithm being used (e.g., HMAC SHA256 or RSA).
- Payload: Contains the claims. Claims are statements about an entity (typically, the user) and additional data.
- Signature: Used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way.
Note: This tool decodes the Base64Url encoded Header and Payload. It does NOT cryptographically verify the signature.
Frequently Asked Questions
Does this tool verify the signature of the JWT?
No. This tool only decodes the Base64Url encoded header and payload for inspection. It does not cryptographically verify the signature against a secret key.