Developer Tool
Paste any JWT to decode its header and payload, and see its issued-at, not-before, and expiration times as readable dates — with a clear expired/valid verdict.
Decoded entirely in your browser — nothing is sent anywhere. This checks timing claims only; it does not verify the signature.
A JWT's signature can only be verified with the issuer's secret or public key, which this tool never has — so it can't tell you whether a token is authentic. What it can tell you, from the payload alone, is whether the token's own timing claims say it should be considered expired: exp (expiration), iat (issued at), and nbf (not valid before), all standard Unix timestamps per RFC 7519.
A token can have a perfectly valid signature and still be expired, and a token can be well within its time window and still be invalid for other reasons (wrong audience, revoked, tampered claims elsewhere). Timing is only one part of validation — a real backend must check the signature and other claims too, not just the dates this tool surfaces.
Related
Check the raw exp/iat values directly if needed.
For token lifetimes expressed as durations instead of timestamps.
Other timestamp formats you might find embedded in tokens or IDs.