Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
BlockSurvey - Privacy-focused surveys, polls & forms
Kannel - Open Source WAP and SMS Gateway
Refiner - Customer Feedback Surveys For SaaS
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
Surveys in Slack by Polly - The world's first fully immersive Slack-based survey product