SendJson

        static string SendJson(string url, string data)
        {
            var httpReq = (HttpWebRequest) WebRequest.Create(url);
            httpReq.ContentType = "application/json";
            httpReq.Method = "POST";
            using (var writer = new StreamWriter(httpReq.GetRequestStream()))
            {
                writer.Write(data);
                writer.Flush();
                writer.Close();

                var httpResp = (HttpWebResponse) httpReq.GetResponse();
                using (var reader = new StreamReader(httpResp.GetResponseStream()))
                    return reader.ReadToEnd();
            }
        }