Webhook delivery payload

Schema

{
  "type": "object",
  "required": [
    "eventType",
    "payload"
  ],
  "properties": {
    "eventType": {
      "type": "string"
    },
    "payload": {
      "type": "object"
    },
    "signature": {
      "type": "string"
    }
  }
}