static void Main(string[] args) { // Find your Account Sid and Auth Token at twilio.com/user/account string AccountSid = "ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"; string AuthToken = "your_auth_token"; var twilio = new TwilioRestClient(AccountSid, AuthToken); var callerId = twilio.AddOutgoingCallerId("+14158675309", "My Home Phone Number", null, null); Console.WriteLine(callerId.ValidationCode); }