Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
Talk360 - Talk360 is a best-in-class communication utility that offers a convenient way to connect with loved ones globally.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
TextMe - TextMe is a free calls and messaging application at both local and international levels.