Generate Secure HMAC Signatures Online

The HMAC Generator computes hash-based message authentication codes (HMACs) using SHA-1, SHA-256, or SHA-512 — combining your message with a secret key to produce a verifiable signature. Essential for verifying API webhooks and request authenticity. Free, no account, runs entirely in your browser.

1. 1

   Enter your secret key in the key field.

2. 2

   Paste your message or payload into the message field.

3. 3

   Select the hash algorithm (SHA-256 recommended) and copy the HMAC result.

4. 4

   Enter the message content you want to sign.

5. 5

   Provide the secret key used for the hashing process.

6. 6

   Copy the resulting HMAC signature for your API request header.

7. 7

   What is an HMAC used for?

8. 8

   HMAC is used to prove that a message came from a specific sender and hasn't been changed, using a shared secret key.