JWT Expiry Checker
The exp (expiration time) claim in a JWT is a Unix timestamp (seconds since 1 January 1970 UTC). After this time the token must not be accepted by any relying party. Checking whether a token has expired is one of the most common debugging tasks when working with authentication systems.
This tool decodes the exp, nbf, and iat claims from your JWT and highlights expired tokens in red. It shows both the absolute timestamp and a relative label ("expired 4 minutes ago", "expires in 2 hours") so you can immediately tell whether a token is still valid.
Useful for debugging login loops, token refresh issues, and expired API keys embedded in JWTs. Works entirely in your browser — paste and check.
How to use
- Paste your JWT token into the input field on the main tool page.
- The header and payload are decoded instantly — review claims, algorithm, and expiry.
- To verify the signature, paste your HMAC secret or PEM public key and click Verify Signature.