Common uses
- Create test tokens for local API and authentication development.
- Generate fixtures for automated tests or QA environments.
- Learn how JWT headers, claims, timestamps and HMAC signatures fit together.
Generate Signed JWT Tokens
Create signed HMAC JWTs with custom payloads, expiration and optional registered claims.
Processed locally. Never uploaded.
Signing data stays in this browser
Signing
Header and payload
Optional registered claims
Signed token
Your signed JWT will appear here.
Use test secrets here. Never paste a production secret on a shared device or include sensitive data in a JWT payload.
How it works
Done in three quick steps
- 1
Choose an HMAC algorithm and enter a secret.
- 2
Add custom JSON and any optional JWT claims.
- 3
Generate, inspect, copy or download the signed token.
About this tool
What you can do with JWT generator
The JWT generator creates HMAC-signed tokens with custom headers, payload data and optional registered claims. Signing uses the browser Web Crypto API, so the secret and generated token do not need to be sent to Gainup's servers.
Tips for better results
- Use long, unpredictable secrets for real HMAC signing systems.
- Do not paste production secrets into a shared device or browser session.
- Treat generated tokens as credentials when their claims grant access to a real service.
Good to know
Frequently asked questions
Clear answers about privacy, quality and how this tool works.