HMAC Generator
Sign a message with a shared secret — the way webhooks (Stripe, GitHub, Shopify) and APIs do.
—Hex
—Base64
● 🔒 Your data is processed locally in your browser with the Web Crypto API and is never uploaded to our servers.
How it works
HMAC (RFC 2104) combines a secret key with a hash function, so only someone with the key can produce or check the signature. Webhook providers send an HMAC of the request body in a header; your server recomputes it with the shared secret and compares. The message must match byte for byte — a single extra space or line break changes the result.