HMAC Generator
Create HMAC-SHA256 and HMAC-SHA512 signatures in hex or Base64. Free webhook signing tool that runs in your browser.
Signature
Enter a secret to generate the signature locally.
Signing uses the Web Crypto API in your browser. The secret is not sent anywhere. Do not leave a production secret on a shared computer.
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Frequently asked questions
What is HMAC Generator?+
Sign a message with a secret using HMAC-SHA256 or HMAC-SHA512 and copy the hex or Base64 signature.
How do I use HMAC Generator?+
Useful for checking Stripe, GitHub, Slack, and Twilio webhook signatures. The secret stays masked and is never sent to a server. Signing uses the browser Web Crypto API
Is HMAC Generator free?+
Yes, HMAC Generator is completely free. No account or sign-up required, and all processing happens in your browser — nothing is sent to a server.
Is my data safe when I use HMAC Generator?+
Yes. HMAC Generator runs entirely in your browser using JavaScript and Web APIs — your input is never uploaded, transmitted, or stored on any server.