curl --request POST \
  --url https://api.hubapi.com/crm/v3/extensions/cards-dev/{appId} \
  --header 'Content-Type: application/json' \
  --data '{
  "title": "PetSpot",
  "fetch": {
    "targetUrl": "https://www.example.com/hubspot/target",
    "objectTypes": [
      {
        "name": "contacts",
        "propertiesToSend": [
          "email",
          "firstname"
        ]
      }
    ]
  },
  "display": {
    "properties": [
      {
        "name": "pet_name",
        "label": "Pets Name",
        "dataType": "STRING"
      }
    ]
  },
  "actions": {
    "baseUrls": [
      "https://www.example.com/hubspot"
    ]
  }
}'

{
  "createdAt": "2019-10-30T03:30:17.883Z",
  "updatedAt": "2019-11-30T03:30:17.883Z",
  "title": "PetSpot",
  "fetch": {
    "targetUrl": "https://www.example.com/hubspot/target",
    "objectTypes": [
      {
        "name": "contacts",
        "propertiesToSend": [
          "email",
          "firstname"
        ]
      }
    ]
  },
  "display": {
    "properties": [
      {
        "name": "pet_name",
        "label": "Pet's Name",
        "dataType": "STRING"
      }
    ]
  },
  "actions": {
    "baseUrls": [
      "https://www.example.com/hubspot"
    ]
  }
}