JWT Signer & Token Generator
Sign HMAC JSON Web Tokens (HS256/HS384/HS512) locally using Web Cryptography API.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. No data is ever transmitted across the network.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
How to Use JWT Signer & Token Generator
Select HS256, HS384, or HS512 and enter your secret key.
Customize the JSON payload object (sub, exp, custom claims).
Copy the compact base64url signed JWT string.
Frequently Asked Questions
Are my secret keys sent to a server?
No, HMAC signing uses the W3C Web Crypto Subtle API locally in your browser memory.
What algorithms are supported?
HS256 (HMAC-SHA256), HS384 (HMAC-SHA384), and HS512 (HMAC-SHA512).
Related Security & Network Tools
View all →Split master passwords into M-of-N threshold shares with GF(256) math.
Generate cryptographically secure 12, 18, or 24-word seed phrases.
Calculate network address, broadcast, usable host IP range, and masks.
Derive secure keys with customizable iterations, salts, and SHA hashes.