JWT Parser

Yes, when using this tool. All processing is done 100% in your browser. Your tokens are never sent to any server. However, be cautious with other online tools that may send your tokens to their servers.

A JWT is expired when the current time exceeds the "exp" (expiration) claim in the payload. This tool shows you if a token is expired, active, or not yet valid based on these time claims.

You can modify the payload, but the signature will no longer be valid unless you have the signing key. This is the security mechanism of JWTs — any modification invalidates the signature.