Secretfield, this information will be sent through as the HTTP header x-webhook-secret. You can use the to authenticate at your side.
And to verify that a webhook was actually sent by Trio, every payload is signed with a signature that is passed through as the HTTP header x-webhook-signature. The signature is encoded and can be replicated by applying HMAC-SHA-256 to the body of the webhook with your specific webhook key, which can be found in your webhook settings page. Below, a simple example of how to generate the signature using Node.js:

