What is JWT Builder?
JWT Builder creates JSON Web Tokens with custom headers, payloads, and signatures. Define claims like expiration, issuer, and subject, then sign with a secret or generate example tokens.
Common Use Cases
API Testing
Create test tokens for authenticated endpoints.
Development
Generate tokens for local development.
Learning
Understand JWT structure by building tokens.
Documentation
Create example tokens for API docs.
How to Use This Tool
- Set the algorithm (HS256, RS256, etc.)
- Add payload claims (sub, iat, exp, etc.)
- Enter your signing secret
- Generate and copy the JWT
Frequently Asked Questions
What algorithm should I use?
HS256 (HMAC) for shared secrets, RS256 (RSA) for public/private key pairs.
What is the exp claim?
Expiration time - tokens become invalid after this Unix timestamp.
Should I put sensitive data in JWTs?
No! JWTs are only encoded, not encrypted. Anyone can read the payload.