Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
IBM Watson Assistant - Watson Assistant is an AI assistant for business.
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
Aivo - Skyrocket your Customer Service and Sales KPIs with a Chatbot powered by Artificial Intelligence. Give time back to people.
Kannel - Open Source WAP and SMS Gateway
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.