HMAC generator

Sign a message with a secret key and get the HMAC as HEX and Base64 — for verifying or producing webhook signatures. Computed in your browser with Web Crypto. Nothing is uploaded.

Message

Secret key Show key

Key encoding

Algorithm

HMAC (hex)

HMAC (Base64)

Everything runs in your browser. No upload, no sign-up.

How it works

STEP 1

Enter the message and key

Paste the payload to sign and your shared secret key. Both stay on your device — they are never sent anywhere.

STEP 2

Pick a hash algorithm

Choose SHA-256 (the common default), or SHA-1, SHA-384 or SHA-512 to match the service you are signing for.

STEP 3

Copy the signature

Copy the HMAC as HEX or Base64 and drop it into your Authorization header, webhook check or test request.