This sample code is written in PHP:

$url = 'https://secure.365villas.com/api/property';
$data = array(
  "action" => "create",
  "property" => [
    "internal_code" => "1",
    "name" => "Villas beach on island",
    "type" => "Villa",
    "brief" => "Luxurious area with famous Saatchi Gallery, Theater Royal, designer shops and fine dining venues.",
    "maxguest" => 4,
    "bedrooms" => 2,
    "bathrooms" => 3,
    "kitchens" => 1,
    "floor" => "3",
    "space" => [
      "value" => 100,
      "unit" => "meters"
    ],
    "phone" => "1832472313",
    "street" => "31 Draycott Ave",
    "city" => "London",
    "state" => "London",
    "country" => "UK",
    "latitude" => 51.492,
    "longitude" => -0.164,
    "allowchildren" => false,
    "allowpet" => true,
    "allowsmoking" => false
);

$username='guest';
$password='secret';

$curl = curl_init();
curl_setopt_array($curl, array(
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_HTTPHEADER => array(
        "cache-control: no-cache",
        "content-type: application/x-www-form-urlencoded",
        "365villaskey: NTZjMjI4OWM4NzkyYTJkZDM5ZTFlNjNkMzQxZmZmMzRhZjM5YTEzMQ==",
        "365villaspass: YmMzZjVkMmUyZTVmYWFlZWYxZjkwNzZmZjcyODhkYmU3ZjY3MmZmYg=="

    ),
    CURLOPT_USERPWD => $username . ":" . $password,
));
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($data));

$response = curl_exec($curl);
curl_close($curl);
$returnData = json_decode($response, true);
print_r($returnData);

Response example data

{
  "code": 200,
  "data": {
    "property_id": "1"
  }
}