Google Pay - Make secure payments right through your Android device.
Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
Proovl - Proovl offers SMS API and messaging solutions.
Kannel - Open Source WAP and SMS Gateway
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
PlaySMS - PlaySMS is a free and open-source management software that offers a flexible web-based mobile portal system that can be made to fit multiple services such as SMS gateway, bulk SMS provider and personal messaging systems etc.