This sample code is written in PHP:

$url = 'https://secure.365villas.com/vros/external-booking';
$data = array(
  'key' => "NTZjMjI4OWM4NzkyYTJkZDM5ZTFlNjNkMzQxZmZmMzRhZjM5YTEzMQ==",
  'pass' => "YmMzZjVkMmUyZTVmYWFlZWYxZjkwNzZmZjcyODhkYmU3ZjY3MmZmYg==",
  'propertyId' => 7,
  'action' => 'getinfo',
  'checkin' => '2017-05-01',
  'checkout' => '2017-05-08',
  'numberofadults' => 3
);

$curl = curl_init();
curl_setopt_array($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"
    ),
));
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

{
  "status": 0,
  "message": "Success",
  "data": {
    "totalRent": 7050,
    "taxTotal": 1692,
    "serviceTotal": 30120,
    "grandTotal": 38862,
    "qtyofnights": 7,
    "propertyName": "Property",
    "propertyId": 7,
    "checkin": "2017-05-01 17:00:00",
    "checkout": "2017-05-08 10:00:00",
    "createdDate": null,
    "cancellationDate": null,
    "numberofadults": 3,
    "numberofchildren": 0,
    "tax": [
      {
        "name": "Tax 1",
        "amount": 705
      },
      {
        "name": "Tax 4",
        "amount": 987
      }
    ],
    "service": [
      {
        "name": "S2",
        "amount": 30000,
        "taxAmount": 0
      },
      {
        "name": "S5",
        "amount": 120,
        "taxAmount": 0
      }
    ]
  }
}