JWT Debugger
Decode JSON Web Tokens and verify HMAC signatures with your secret — entirely in your browser.
Runs in your browser Verify HS256/384/512 Expiry detection
{
"alg": "HS256",
"typ": "JWT"
}{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022
}SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
What it does
Decode + verify
Decode header and payload, then verify HMAC signatures using WebCrypto and your secret. No server round-trip.
Claim awareness
Highlights iat, exp, and nbf as readable timestamps and flags expired or not-yet-valid tokens automatically.
Privacy-first
Tokens and secrets are never uploaded. All cryptography happens locally in your browser.
Frequently Asked Questions
Quick answers about the JWT debugger.
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