JWT Decoder, Signer & Verifier
Decode, verify, and sign JSON Web Tokens instantly. All algorithms supported — your tokens and private keys never leave your device.
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Frequently Asked Questions
All major algorithms: HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, and PS256.
Yes. Paste your JWT and your public key (PEM or JWK format) to verify the signature. The verification runs entirely in your browser.
Decoding reads the payload without checking the signature — useful for inspection. Verifying confirms the signature is valid using the correct key, proving the token has not been tampered with.
Yes. Choose your algorithm, enter a payload, provide your secret or private key, and the tool generates a signed JWT ready for use in your application.
Yes. Unlike jwt.io and similar tools, this tool runs 100% client-side. Your tokens and keys never leave your device.