Create and generate JSON Web Tokens (JWT) online with custom headers, payloads, and signatures. Free JWT generator tool for developers.
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A JWT creator helps you generate signed tokens for development and QA by assembling a header, payload (claims), and signature. Use it to prototype authentication flows, test Authorization: Bearer integration, and learn how algorithms like HS256 (HMAC) and RS256 (RSA) sign data.
What is a JWT?
A JSON Web Token is three Base64URL‑encoded parts joined by dots: header.payload.signature. The header declares type and alg (for example, HS256, RS256). The payload carries claims such as iss (issuer), sub (subject), aud (audience), exp (expiration), and custom fields. The signature is computed over header and payload with a shared secret (HMAC) or private key (RSA/ECDSA), allowing recipients to verify integrity and authenticity statelessly.
How JWTs work
A server authenticates a user, signs a token, and returns it to the client. Clients include the token in Authorization: Bearer <JWT>. The server verifies the signature, checks exp and nbf, then applies authorization based on scopes/roles. Because JWTs are self‑contained, they scale well across microservices and CDNs, but require strict key rotation, short lifetimes, and careful claim design to avoid bloat or leakage.
About the JWT Creator tool
Choose HS256/HS384/HS512 for HMAC with a shared secret or RS256/ES256 for asymmetric keys. Set standard claims (iss, sub, aud, exp, nbf, iat, jti) and add custom claims, then sign to produce the JWT. Copy the token into curl or your HTTP client to test protected endpoints. Don’t expose real secrets in browsers; never store private keys in client code.
FAQ
Which algorithms are supported?
Common algorithms include none (for unsecured tokens), HS256/384/512 (HMAC), and RS256/384/512 or ES256/384/512 (RSA/ECDSA). Availability in this tool may vary by browser crypto support.
Are tokens encrypted?
No—JWTs are signed, not encrypted. Anyone with the token can read its payload. If confidentiality is required, use JWE (JSON Web Encryption) or transport‑level security and avoid exposing sensitive claims.
JWTs are powerful when used carefully: choose the smallest practical claim set, prefer short lifetimes, and rotate keys. This tool helps you learn and prototype safely before implementing production‑grade token services.