JWT Generator
Generate signed JSON Web Tokens for development and tests. HMAC signing runs locally in your browser with the Web Crypto API.
Reviewed May 25, 2026. Privacy model: tool input is processed in your browser and is not uploaded to BytePane servers.
JWT Generator Notes
JSON Web Tokens are defined by RFC 7519. A signed JWT has three Base64Url-encoded parts: header, payload, and signature. The header declares the algorithm, the payload carries claims such as sub, iss, aud, iat, and exp, and the signature protects the first two parts from tampering.
RFC 8725, the JWT Best Current Practices document, recommends strict algorithm verification, sufficient key entropy, and explicit issuer and audience validation. Treat tokens generated here as development fixtures only. Production tokens should be issued by your authentication service with managed keys, short lifetimes, and server-side audit controls.
Frequently Asked Questions
Is this JWT generator safe for secrets?
The signing operation runs in your browser with the Web Crypto API. BytePane does not send the payload or secret to a server. For production systems, still generate tokens server-side and keep signing keys in a secret manager.
Which algorithms does this tool support?
This tool supports HMAC JWT algorithms HS256, HS384, and HS512. RSA and ECDSA tokens require private key handling and should usually be generated by your auth server or test fixture code.
Can I generate an expired JWT for tests?
Yes. Use a negative expiration window or the Expired test button. The exp claim is set to a Unix timestamp in the past so your middleware can exercise expired-token handling.