HMAC Generator
Create an HMAC signature from text or a file with a secret key: SHA-256, SHA-512, SHA-1 or MD5, as HEX and Base64. Paste a webhook signature to check it.
How to create an HMAC signature
- Paste the content to sign or choose a file.
- Enter the secret key (pick HEX or Base64 if your key is written that way) and choose the algorithm; the signature appears right away.
- To check one, paste the signature you received into "Verify a signature" to see whether it matches.
Frequently asked questions
An HMAC is a signature made from the content and a secret key only the two sides know. Payment gateways, GitHub, Shopify and others send it along so the receiver knows the content really came from them and was not changed on the way.
Paste the exact content you received, enter the secret key, pick the algorithm the service uses (usually SHA-256), then paste the signature into the verify box. HEX and Base64 both work, and a prefix such as sha256= is removed for you.
The content must be identical down to each character: one extra space, a blank line at the end or JSON that was reformatted all give a different signature. Check the key too (text, HEX or Base64) and the algorithm.
SHA-256 is the most common and the default. SHA-512 gives a longer signature. Use MD5 and SHA-1 only when an older system requires them.
It is completely free and needs no sign-up.
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