In order to receive webhooks you shall have an endpoint to receive a "POST" request with an JSON conforming with the following structure:

{
  "payorId": "string", // this is your own payor id
  "event": "string",   // the event name
  "timestamp": Date,   // the date-time the event was triggered
  "data": {}           // the event payload (see examples)
}

The event and data fields will differ from each event you subscribed to on Add Webhook.