try
{
string strResult = “”;
//Prepare you post parameters
var postValues = new List<KeyValuePair<string, string>>();
//Your authentication key
postValues.Add(new KeyValuePair<string, string>(“authkey”, “YourAuthKey”));
//Multiple mobiles numbers separated by comma
postValues.Add(new KeyValuePair<string, string>(“mobiles”, “9999999”));
//Sender ID,While using route4 sender id should be 6 characters long.
postValues.Add(new KeyValuePair<string, string>(“sender”, “102234”));
//Your message to send, Add URL encoding here.
string message = HttpUtility.UrlEncode(“Test message”);
postValues.Add(new KeyValuePair<string, string>(“message”, message));
//Select route
postValues.Add(new KeyValuePair<string, string>(“route”,”default”));

//Prepare API to send SMS
Uri requesturl = new Uri(“http://login.yourbulksms.com/api/sendhttp.php”);
//create httpclient request
var httpClient = new HttpClient();
var httpContent = new HttpRequestMessage(HttpMethod.Post, requesturl);
httpContent.Headers.ExpectContinue = false;
httpContent.Content = new FormUrlEncodedContent(postValues);
HttpResponseMessage response = await httpClient.SendAsync(httpContent);

//Get response
var result = await response.Content.ReadAsStringAsync();
strResult = result.ToString();
response.Dispose();
httpClient.Dispose();
httpContent.Dispose();
}
catch (Exception ex)
{
throw ex;
}

//Your authentication key
String authkey = “YourAuthKey”;
//Multiple mobiles numbers separated by comma
String mobiles = “9999999”;
//Sender ID,While using route4 sender id should be 6 characters long.
String senderId = “102234”;
//Your message to send, Add URL encoding here.
String message = “Test message”;
//define route
String route=”default”;

URLConnection myURLConnection=null;
URL myURL=null;
BufferedReader reader=null;

//encoding message
String encoded_message=URLEncoder.encode(message);

//Send SMS API
String mainUrl=”http://login.yourbulksms.com/api/sendhttp.php?”;

//Prepare parameter string
StringBuilder sbPostData= new StringBuilder(mainUrl);
sbPostData.append(“authkey=”+authkey);
sbPostData.append(“&mobiles=”+mobiles);
sbPostData.append(“&message=”+encoded_message);
sbPostData.append(“&route=”+route);
sbPostData.append(“&sender=”+senderId);

//final string
mainUrl = sbPostData.toString();
try
{
//prepare connection
myURL = new URL(mainUrl);
myURLConnection = myURL.openConnection();
myURLConnection.connect();
reader= new BufferedReader(new InputStreamReader(myURLConnection.getInputStream()));

//reading response
String response;
while ((response = reader.readLine()) != null)
//print response
Log.d(“RESPONSE”, “”+response);

//finally close connection
reader.close();
}
catch (IOException e)
{
e.printStackTrace();
}