curl --request GET \
  --url https://api.octolane.com/v1/contacts \
  --header 'x-api-key: <api-key>'

{
  "success": true,
  "message": "<string>",
  "data": {
    "custom_field_definitions": {
      "last_action_date": {
        "current_name": "Last Action Date",
        "property_name": "custom__last_action_date",
        "attribute_type": "date",
        "metadata": null
      },
      "kola": {
        "current_name": "Kola",
        "property_name": "custom__kola",
        "attribute_type": "multi_select",
        "metadata": {
          "options": [
            {
              "label": "E",
              "value": "e-532837",
              "color": "indigo"
            }
          ]
        }
      }
    },
    "has_more": true,
    "next_cursor": "<string>",
    "limit": 123,
    "contacts": [
      {
        "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "first_name": "<string>",
        "last_name": "<string>",
        "email": "jsmith@example.com",
        "custom_fields": {}
      }
    ]
  }
}