JWT Generator
Runs entirely in your browser
Build and sign a JWT with HS256, HS384 or HS512 directly in your browser — ideal for development and testing.
What is JWT Generator?
JWT Generator builds a JSON Web Token from a header and payload you define, then signs it with HMAC (HS256, HS384 or HS512) using a secret you provide. It's useful for generating test tokens during development without running a backend.
How to use JWT Generator
- Edit the Header and Payload JSON as needed.
- Choose an algorithm and enter a secret.
- Click Generate & Sign, then copy the resulting token.
Features
- Supports HS256, HS384 and HS512 signing.
- Fully editable header and payload JSON.
- Uses the Web Crypto API for signing — not a hand-rolled implementation.
- 100% client-side — your secret and claims never leave your browser.
Frequently Asked Questions
Is my secret uploaded to a server?
No. Signing happens entirely in your browser using the Web Crypto API. Still, avoid pasting a real production secret into any web tool — use this for development and testing tokens.
Which algorithms are supported?
HS256, HS384 and HS512 — HMAC-based signing with a shared secret. RSA/EC-signed tokens (RS256, ES256, etc.) require a private key pair and aren't supported here.
Can I edit the payload freely?
Yes. The payload is any valid JSON object — add whatever claims you need for testing, such as sub, exp or custom fields.
Can I verify the token this generates?
Yes, with the same secret and algorithm. Use the JWT Decoder to inspect the header and payload (decoding never verifies a signature).