JWT Generator
Create signed JWT tokens for testing authentication flows.
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token with three parts: header.payload.signature, each Base64URL-encoded. The signature proves the token wasn't tampered with.
Security warning
Never use this tool to sign real production tokens. Real JWTs should be signed on a server with a secret key that never leaves the server environment. Use this tool only for local testing and learning.
Privacy
Everything runs in your browser. Your secret and payload are never uploaded.
Frequently Asked Questions
What is a JWT generator?
A tool that creates a signed JSON Web Token from a header, payload, and secret key. Used for testing authentication flows.
Is this safe to use?
Only for testing. Never sign real tokens in a browser tool — secrets should never leave your server.
Which algorithms are supported?
HS256, HS384, and HS512 (HMAC-SHA). RS256 (RSA) is not supported because it requires a private key.
What claims are added automatically?
iat (issued at) is always added. exp (expiration) is added if you set 'Expires in' > 0.
Is my secret uploaded?
No. Everything runs in your browser.