Inspect any JWT, offline.

Paste a token — see every claim, every signature, and the security issues an attacker would find first. Nothing leaves your browser.

● Offline No network Web Crypto HS256 · HS384 · HS512 · none

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Header

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Payload

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Signature

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Security analysis

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Paste a JWT above. The analysis runs offline — no token leaves this page.

Enter a secret to verify the HMAC signature in-browser via Web Crypto.