MessageBird Chat API - Connect with your customers through different messaging apps
Kannel - Open Source WAP and SMS Gateway
Wavecell - Wavecell simplifies real-time cloud communications using SMS, Chat Apps, Video Interaction and Voice solutions.
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
Twilio - Brings voice and messaging to your web and mobile applications.
KAPSYSTEM - KAP Computer Solutions Pvt. Ltd.,