Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
botwick - Build your own SMS-based text bot
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
Abot for Slack - Trusted by over 1000 Slack teams ✅. Abot is a simple and highly configurable app for anonymous feedback messages and more. If you want to create a poll on Slack or use it as an anonymous suggestion box you just need to type a simple command.
Kannel - Open Source WAP and SMS Gateway
Estherbot - Transform your resume into a bot.