Twilio - Brings voice and messaging to your web and mobile applications.
E-goi - Email Marketing companies, SMS Marketing, software email marketing.
Atomic SMS Sender - Free bulk SMS software to send bulk text messages from PC
Tellephant - Helping you build incredible chatbots and integrate WhatsApp, Google, Facebook, SMS and more to your communication stack in seconds. All at the cheapest rates out there.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Swift SMS Gateway - SMS Gateway is your bridge between the Internet and the world of cell phone SMS text messaging.