Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
Officevibe - Officevibe is an employee survey platform with the mission of improving company culture. Measure and improve your culture in less than 5 minutes per month, with our simple surveys.
Kannel - Open Source WAP and SMS Gateway
Qualtrics Employee Experience - Qualtrics Employee Experience Management Platform helps improve the way people make decisions by creating amazing employee experiences.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
15Five - 15Five software elevates the performance and engagement of employees by consistently asking questions and starting the right conversations.