HMAC Signature
Compute HMAC message authentication codes from any text and secret key, using the Web Crypto API right in your browser. Supports HMAC-SHA1, HMAC-SHA256 and HMAC-SHA512, with hex or Base64 output. Your message and key never leave this page.
Result appears here.
How to use the HMAC Signature tool
Compute an HMAC (Hash-based Message Authentication Code) from a message and a secret key. HMAC verifies both the integrity and the authenticity of a message — only someone who knows the key can produce the same signature.
Steps
- Enter the secret key shared between sender and receiver.
- Type or paste the message to authenticate.
- Pick the hash algorithm (SHA-256 is the common default) and the output encoding (hex or Base64), then click Compute HMAC.
Common uses: signing webhook payloads, API request signing, and verifying that a message was not tampered with. The computation happens locally with the browser's native Web Crypto API.