Twilio Flex - The programmable contact center platform 📱
MessageBird Chat API - Connect with your customers through different messaging apps
Voiceflow - Build voice apps in your browser without coding
MessageBird API on StdLib - Purchase numbers, send SMS and more with one line of code
Jovo - 🗣 Build cross-platform apps for Alexa and Google Home
LoopMessage - LoopMessage is a perfect macOS tool for personalized mass messaging via iMessage/SMS, WhatsApp, Facebook Messenger, Telegram, Viber, and Skype.