JWT Decoder & Verifier

100% client-side. Your data never leaves this page. Verify: DevTools → Network.

Token

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Secret / Public Key optional, only for verify

Header

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Payload

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Paste a JSON Web Token to decode its header and payload instantly. Add an HMAC secret or a PEM public key to verify the signature - HS256/384/512, RS256 and ES256 are checked with the browser's Web Crypto API. Nothing is sent anywhere; the token and key stay in this tab.