I Have not Provided the UserName And sender ID b'coz u have to purchase sms from sms Seller then u will get this thing and authorized number is the number to get report of sms send
take all the mobile no u want to send sms in datatable as dt
for(int i=0;i<dt.rows.count;i++)>
{
string url1 = "http://api.mVaayoo.com/mvaayooapi/MessageCompose?user=User_Name&senderID=ID SMS&receipientno=" + dt.Rows[i][0].ToString() + "&msgtxt='"+TextBoxName.Text+"' API&state=4";
WebRequest request = HttpWebRequest.Create(url1);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream s = (Stream)response.GetResponseStream();
StreamReader readStream = new StreamReader(s);
string dataString = readStream.ReadToEnd();
response.Close();
s.Close();
readStream.Close();
}
this works in my asp.net with c# web application hope ur query is solve