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TOOL #371 · JWT EXPIRY CHECKER

JWT Expiry Checker

Check JWT expiry with configurable clock leeway and refresh thresholds, simulate any point in time, visualize token age and lifetime, diagnose nbf/iat anomalies, batch-check up to 5,000 tokens, export CSV, and convert NumericDate timestamps—entirely in your browser.

exp / nbf / iatClock leewayRefresh windowTime simulationLifetime progress5,000-token batchNumericDate converter100% local

JWT

Waiting
Status—
Expires—
Remaining—
Token age—
Lifetime—
Lifetime used—

Expiry timeline

issued —refresh —expires —

Token timing

Application settings

Decoded payload

Expiry assessment
Waiting
Time checks do not verify signature, issuer, audience, revocation, token type, or authorization policy.
Shareable report




Batch expiry checker
Paste one JWT per line. The same leeway, refresh threshold and simulated time from Expiry Lab are used. Maximum 5,000 tokens.
Total0
Valid0
Refresh0
Expired0
No exp0
Invalid / future0
Batch results


NumericDate ↔ ISO converter
Converted value


What exp means
The exp claim is a NumericDate after which the token must not be accepted. This checker compares it with the selected clock and optional leeway.
Clock leeway
Small leeway can accommodate clock skew between systems. It should be deliberately limited and should not become a general extension of token lifetime.
Refresh window
The refresh threshold is operational guidance: it marks when a client may want to obtain a replacement before actual expiry. It does not change the JWT's exp value.
nbf and iat
nbf indicates when a token may start being accepted. iat records issue time and can help calculate token age and detect obviously future-issued tokens.
Batch triage
Batch mode is useful for local debugging and inventories. Tokens remain in the browser; results can be exported as CSV without uploading them.
Production validation
Expiry is only one acceptance rule. Production systems also need cryptographic verification and checks for issuer, audience, token type, revocation/key rotation and protocol-specific requirements.