JWT Generator in your browser, no signup

Create and signs JSON Web Tokens (JWTs) using HS256/384/512 algorithms - useful for testing an API that expects a JWT, learning how JWT structure works, or generating a token for a development/testing environment without setting up a full authentication server.

Anything that hashes, generates keys or checks a password should stay on your machine. If a site asks you to upload a secret, close the tab.

JWT Generator is a good fit when testing protected API endpoints in development.

In plain English

JWT Generator is built around a few practical wins, not a long feature list:

• Speeds up API auth testing without full identity stack setup.
• Helps visualize JWT structure and claim behavior.
• Useful for QA, integration tests, and local debugging.
• Supports common HMAC JWT signing variants.

How to run it

1. Define payload claims. Set subject, issuer, expiry, roles, and custom claims as needed.
2. Choose signing algorithm. Select HS256/384/512 matching target API verification expectations.
3. Sign token with secret. Generate JWT string and inspect decoded header/payload output.
4. Test and verify. Use token in dev API requests and confirm auth behavior.

Real situations

• Testing protected API endpoints in development.
• Simulating role-based tokens for frontend QA.
• Debugging claim parsing and expiry handling logic.
• Building auth test fixtures for automated integration suites.

Small habits that help

• Use short expirations for testing security-sensitive flows.
• Never use production signing secrets in browser tools.
• Include only required claims to keep tokens minimal.
• Validate algorithm expectations on server to prevent misuse.

Skip these

• Using generated dev tokens directly in production systems.
• Forgetting expiry claim and creating long-lived insecure tokens.
• Sharing JWTs publicly in logs or screenshots.
• Assuming unsigned/weakly signed tokens are safe for auth.

Does anything leave your device?

JWT Generator runs in your browser. The file or text you paste stays on your device. There is no account, and nothing is stored on a ToolBox server for this job.

Related tools worth opening next

If this is one step in a longer job, these usually come after it:

• JWT Encoder - Encode and sign JWTs with HS/RS/ES/PS algorithms in the browser
• JWT Decoder - Decode and inspect JWT tokens
• RSA Key Generator - Generate RSA key pairs and export them in PEM format

FAQ

Can I use a token generated here in a real production system?

This tool is best suited for testing, learning, and development purposes - for real production authentication, tokens should be generated and signed server-side using your application's actual secret keys and infrastructure, not a third-party browser tool.

What's the difference between HS256, HS384, and HS512?

They're the same HMAC-based signing approach using different hash functions (SHA-256, SHA-384, SHA-512) - higher numbers mean a longer, more computationally intensive signature, though HS256 is the most commonly used default across most systems.

Is my secret key safe when generating a token here?

Signing happens in your browser, but as a general precaution, use a test/throwaway secret key here rather than a real production secret, especially since JWTs are often used for actual authentication.

Open the JWT Generator when you are ready. It is free, and you do not need an account.