HMAC Generator
Generate a keyed HMAC digest (SHA-1/256/384/512) from a message and secret key, entirely in your browser.
How to Generate an HMAC Signature for Free
1. Paste the message or payload you need to sign into the Message box.
2. Enter the shared secret key — the same one the other party uses to verify the signature (e.g. a webhook signing secret).
3. Choose the hash algorithm (SHA-256 is the common default) and the output format your system expects.
4. Click Generate HMAC and copy the digest to compare against the value you're verifying.
Computed Locally, Key Never Transmitted
The HMAC is signed entirely on your device using your browser's built-in Web Crypto API. Neither the message nor the secret key is ever uploaded or logged anywhere, which makes this safe to use with real API keys and webhook secrets.