Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
Scout - Scout ♥ monoliths.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
botwick - Build your own SMS-based text bot
Kannel - Open Source WAP and SMS Gateway
Talera - Meet your new AI powered recruiting co-ordinator.