curl --request GET \
  --url https://demo.spreecommerce.org/api/v2/storefront/countries/{iso}

{
  "data": {
    "id": "1",
    "type": "country",
    "attributes": {
      "iso": "US",
      "iso3": "USA",
      "iso_name": "UNITED STATES",
      "name": "United States",
      "states_required": true,
      "zipcode_required": true,
      "default": true
    },
    "relationships": {
      "states": {
        "data": [
          {
            "abbr": "NY",
            "name": "New York"
          }
        ]
      }
    }
  },
  "included": [
    {
      "abbr": "NY",
      "name": "New York"
    }
  ]
}