{
  "webhook": {
    "name": "My Hook",
    "url": "http://example.com/my-hook",
    "events": [
      "subscribe",
      "unsubscribe",
      "sent"
    ],
    "sources": [
      "public",
      "system"
    ],
    "headers": [
      {
        "name": "CUSTOM-SIGNATURE-NAME",
        "value": "secret",
        "is_signature": true
      },
      {
        "name": "CUSTOM-HEADER-NAME",
        "value": "customvalue",
        "is_signature": false
      },
    ]
  }
}

{
  "webhook": {
    "cdate": "2016-01-01T12:00:00-00:00",
    "listid": "0",
    "name": "My Hook",
    "url": "http://example.com/my-hook",
    "events": [
      "subscribe",
      "unsubscribe",
      "sent"
    ],
    "sources": [
      "public",
      "system"
    ],
    "links": [],
    "id": "1",
    "headers": [
      {
        "name": "CUSTOM-SIGNATURE-NAME",
        "value": "", // signature returns empty value because it's secret
        "is_signature": true
      },
      {
        "name": "CUSTOM-HEADER-NAME",
        "value": "customvalue",
        "is_signature": false
      },
    ]
  }
}