Free HMAC Generator
Generate an HMAC-SHA256 signature online using a message and secret key. Useful for API testing, webhook verification, request signing, and cryptographic integrity checks.
How to Use the HMAC Generator
Enter the message to sign and the secret key, then click Generate HMAC (SHA256). The tool computes the HMAC locally in your browser and shows the hexadecimal signature in the output field. This is useful for reproducing signatures during API testing and debugging.
Key Features
- Generates HMAC signatures using SHA-256
- Useful for webhook verification and signed API requests
- Processes the message and secret locally in the browser
- Produces a standard hexadecimal output
- Simple workflow for quick testing and comparison
What is HMAC?
HMAC stands for Hash-based Message Authentication Code. It combines a secret key with a hashing algorithm to produce a signature that helps confirm both message integrity and authenticity. Many APIs and webhook providers rely on HMAC signatures to verify that a request was created by a trusted sender.