Security & Tokens
JWT Token Inspector, Claims Decoder & Security Checker
Decode JSON Web Tokens (JWT), inspect header algorithms (RS256/HS256), verify payload claims (iss, sub, exp), and check token expiration status.
Input JWT Token
Output Result
About JWT Token Inspector & Decoder & Security Considerations
Everything you need to know about how this utility processes data safely in your browser.
Does this tool send my JWT token over the network?
No, JWT decoding is performed client-side using base64url decoding. Your secret tokens remain strictly on your local machine.
What do the standard JWT claims mean?
`exp` is expiration timestamp, `iat` is issued-at time, `iss` is issuer identity, and `sub` is the user subject identifier.
What is the 'Alg: none' vulnerability?
It is an exploit where attackers forge tokens by setting the algorithm to 'none' to bypass signature verification on poorly configured servers.