JWT Generator

Create signed JSON Web Tokens from a JSON payload object. Select an HMAC algorithm (HS256/384/512), enter your secret key, and click Run. ECDSA, PS256, and EdDSA are not supported.

  • Runs entirely in your browser
  • No data stored or sent to a server
  • Free forever — no signup
  • Instant conversion

Input and Output

Use the interactive encoder and decoder on this page to process your text.

Learn more about JWT generation

How to Generate JWT Tokens for Testing

JWT Generation

When to Generate JWTs

Generate signed JWTs when building test fixtures, prototyping API clients, or debugging authorization flows — without setting up a token issuer. Paste a JSON payload object, choose an HMAC algorithm, and provide a signing secret. The header (alg, typ) is added automatically.

Supported Algorithms

This tool signs tokens with HMAC algorithms (HS256, HS384, HS512). RS256 signing requires a private key and is not supported in-browser. The output is a complete three-part JWT ready for Authorization headers.

Common Mistakes

  • Using production secrets in client-side code — this tool is for local testing only
  • Forgetting exp — tokens without expiration never expire in tests either
  • Invalid JSON in header or payload — both must parse before signing

Security Note

Never embed signing secrets in production client-side code. Use this tool only for local development and testing. Inspect generated tokens with the JWT Signature Checker before relying on them in integration tests.

Frequently asked questions

Does this add an iat claim automatically?

Yes. If your payload does not include iat, the tool adds the current Unix timestamp.

Can I generate RS256 tokens?

Not currently. Use HS256/384/512 for HMAC-signed test tokens, or sign RS256 tokens with your backend.

Is my secret sent to a server?

No. Signing runs entirely in your browser using the Web Crypto API.