JWT Decoder

Decode and inspect JSON Web Tokens safely (offline & verification-free).

Encoded JWT header.payload.signature

Header (Algorithm & Type)

Payload (Data Claims)

Decode JSON Web Tokens Securely

A JSON Web Token (JWT) is incredibly popular for transmitting authentication data and session status within modern REST APIs. Because JWTs often carry sensitive user permissions or behavioral claims, you shouldn't rely on third-party server tools to inspect them. Our completely local JWT Decoder rapidly splits the token into its constituent base64 encoded parts and parses out the raw JSON securely.

Key Security Benefit

By operating purely as an offline client-side script, this decoder reads and displays the Header (the token configuration) and Payload (the actual claims) without communicating with a centralized verification server. This mitigates the risk of exposing your application's architecture or private bearer tokens to untrusted analytics trackers.

Anatomy of a JWT

Header: Identifies the hashing algorithm used (such as HS256).
Payload: Contains public claims, like expiration time (`exp`) and the issued-at time (`iat`), or user ID representations.
Signature: The encrypted hash used to verify token integrity. Note: Our tool decodes only the human-readable payload.