var request = (HttpWebRequest)WebRequest.Create("http://url"); request.ContentType = "application/json"; request.Method = "POST"; using (var streamWriter = new StreamWriter(request.GetRequestStream())) { string json = new JavaScriptSerializer().Serialize(new { user = "Foo", password = "Baz" }); streamWriter.Write(json); } var response = (HttpWebResponse)request.GetResponse(); using (var streamReader = new StreamReader(response.GetResponseStream())) { var result = streamReader.ReadToEnd(); }