Decode JSON Web Tokens instantly to see their contents. Processed entirely in your browser.
A JSON Web Token (JWT) is a compact, URL-safe token format defined by RFC 7519 for securely transmitting information between parties. A JWT has three dot-separated parts: a Base64url-encoded header (algorithm), payload (claims like user ID, roles, expiration), and a signature for integrity verification. JWTs are the industry standard for authentication in modern web applications, APIs, and single sign-on (SSO) systems.
Developers frequently need to inspect JWTs during authentication debugging or security auditing. Our decoder instantly parses the token, displaying header and payload in formatted JSON with clear labels for common claims like exp (expiration), iat (issued at), sub (subject), and iss (issuer). Since JWTs can contain sensitive information, decoding must happen locally—our tool never transmits your tokens anywhere.
This tool decodes and displays contents but does not verify the cryptographic signature, which requires the server's secret key. Signature verification should be done server-side.
Yes. Our tool processes everything locally—your token is never transmitted. Avoid pasting JWTs into tools that send them to remote servers.
The exp (expiration time) claim specifies when the token becomes invalid as a Unix timestamp. After this time, the server should reject the token and require re-authentication.