SMTP to SMS API
Developers / system administrators can send SMTP to SMS by using our regular email-to-SMS solution. However, we do not recommend using email-to-SMS for non-trivial applications, primarily because the need to block email spam on our SMTP servers can cause delays in delivery of your SMSs. The email to SMS facility also has fewer features and a lower throughput than other APIs.
Our recommended solution is the HTTP to SMS API (EAPI), which offers higher volumes, code samples, and more features.