MMaxTools

JWT Generator

Create a signed HS256 JWT from your own payload and secret — locally.

The JWT Generator builds a signed HS256 JSON Web Token from a payload you write and a secret you provide. Type your claims as JSON — subject, expiry, issuer, or anything your API expects — and the tool assembles the header, encodes the payload, computes the HMAC-SHA256 signature locally, and outputs the complete three-part token.

This is the fastest way to mint a test token for local development, integration tests or API debugging without standing up an identity server. The default payload includes standard iat and exp claims so your token behaves realistically out of the box — edit them freely.

Security matters: the signature is computed in your browser with Web Crypto and the secret never leaves your machine. Only use HS256 for systems that share a symmetric secret; production systems typically use RS256/ES256 with public-key verification.

How to use the JWT Generator

  1. Edit the payload JSON — keep valid JSON syntax.
  2. Set the HMAC secret your verifying server expects.
  3. Click 'Generate HS256 token'.
  4. Copy the complete token.
  5. Use it in Authorization headers or API tests; verify with your server.

Frequently asked questions

What does HS256 mean?

It is the JWT signing algorithm: HMAC with SHA-256, where the same secret both signs and verifies the token. HS256 is simple and fast, ideal when one trusted party holds the secret — for distributed systems prefer RS256 or ES256.

Can this generate RS256 tokens?

No — RS256 requires a private key that cannot be used safely in a browser page. This generator produces HS256 tokens with your shared secret, which covers local testing and most internal API scenarios.

Is my secret sent anywhere?

Never — signing happens entirely in your browser using the Web Crypto API. The token itself is generated locally and nothing is uploaded, so you can safely use real development secrets.