webhookId
,
which identifies the specific webhook that triggered the event. In addition, when POST-ing data to the callback URL,
Coinbase will include a header entry in the HTTP request. Its key is “x-coinbase-signature” and its value is generated by concatenating the webhookID and the request body, as an byte array, then hashed using the HMAC-SHA256 algorithm.
Client side can generate a corresponding hash and compare it with the signature provided in the request header to ensure that the request indeed originated from Coinbase.
To locate your webhook UUID, navigate to the portal and view the webhook configuration details.
Here are some code examples on how to verify the HMAC signature when receiving a webhook update.