JWT Inspector
Decode JWT headers and payloads instantly — inspect claims, expiry, and algorithm before trusting a token. Debug auth failures in seconds — local processing, free, no signup.
How to Use the JWT Inspector
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Frequently Asked Questions
What does a JWT contain?
Three base64 parts: header (algorithm), payload (claims like sub, exp, iat), and signature. Paste a token to read all three sections with expiry converted to dates.
Does inspecting validate the signature?
Structure decodes always; signature verification needs the secret or public key. Never trust claims from an unverified token in production code.
Why is my token expired?
Compare the exp claim against current Unix time — clock skew beyond a minute also fails strict validators. Regenerate tokens with realistic lifetimes.
Is my token uploaded?
No — decoding runs locally in your browser. Tokens never leave your device, but never paste production secrets into any web tool.
Which sample tokens ship with it?
HS256 (expired) and RS256 (valid) presets plus Clear. Inspect demands exactly 3 dot-separated parts, then reports EXPIRED vs Valid-until ISO dates, missing exp/iss, and algorithm, typ, kid, sub, aud, iat, nbf and jti rows. Copy confirmations reset after 1500 ms and the report downloads as jwt.json.
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Last updated October 2026