JWT Token Generator & Signer
Create, sign, and test custom JSON Web Tokens (JWT) client-side. Set expiration timers, subject claims, issuer, role arrays, and HMAC secret keys. 100% private — tokens are computed entirely in your browser via the Web Crypto API.
Frequently Asked Questions
Q:What is a JSON Web Token (JWT)?
A JWT is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. It consists of three Base64URL-encoded parts separated by dots: Header, Payload, and Signature.
Q:How are JWTs signed?
HMAC algorithms (HS256, HS384, HS512) use a shared secret key to hash the Base64URL-encoded Header and Payload (header.payload). Anyone with the secret key can verify or generate valid tokens.