Kannel - Open Source WAP and SMS Gateway
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
Power SMPP - Enterprise grade messaging software
KAPSYSTEM - KAP Computer Solutions Pvt. Ltd.,
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
Twilio - Brings voice and messaging to your web and mobile applications.