An event, as it is posted to a webhook

Signed as Standard Webhooks signs (https://www.standardwebhooks.com): webhook-signature is v1, and the base64 of HMAC-SHA256 over <webhook-id>.<webhook-timestamp>.<the body>, keyed with the bytes the webhook's secret is the base64 of (what follows whsec_); libraries that check it exist for most languages. A delivery has succeeded when the answer's status is 2xx; another status, no connection, and no answer within 10 seconds are failures, and it is sent again 5 seconds, 5 minutes, 30 minutes, 2 hours, 5 hours, 10 hours and 10 hours later (--webhook-retry-seconds), then given up. What is to be sent is in the store: a control plane that starts again goes on with it. The same event may come twice (an answer lost on its way back is a failure here): the receiver tells by webhook-id. Sent to the address that was checked to be on the public internet, connected to by that address.