JWT Generator
Generate signed JSON Web Tokens (JWT) with HS256, HS384, or HS512 algorithms. Set custom claims, configure expiry, and verify existing tokens — all client-side, no secrets sent to a server.
⚠ This token is generated client-side. Never use this tool with production secrets - treat any secret you type here as potentially exposed.
JSON Web Token (JWT) Reference
A JWT consists of three Base64URL-encoded parts separated by dots: header.payload.signature. The header declares the algorithm. The payload carries claims (key-value assertions about the subject). The signature is an HMAC of the header and payload using a secret key - it lets the server verify the token has not been tampered with.