JWT Generator
If header uses alg=none, signature will be empty. For HMAC algorithms, provide a secret.
Frequently Asked Questions
What signing algorithms are supported?
This tool generates JWTs signed with HMAC-SHA256 (HS256).
Is my secret uploaded?
No. Token generation is performed client-side in your browser using the Web Crypto API.
Can I customise the header and payload?
Yes. You can edit the JSON header and payload freely before signing.
Example input/output
Input: Header: {"alg":"HS256","typ":"JWT"} / Payload: {"sub":"1234","name":"Ada"} / Secret: mysecret
Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0IiwibmFtZSI6IkFkYSJ9.[signature]
How it works
This tool Base64url-encodes the header and payload JSON, concatenates them with a dot, then signs the result using HMAC-SHA256 with the Web Crypto API. The resulting signature is Base64url-encoded and appended to form the final JWT. Processing runs in your browser.
Common use cases
- Generate signed JWTs for API authentication testing
- Create JWT tokens with custom claims for unit tests
- Produce sample JWTs for API documentation examples