LoopMessage - LoopMessage is a perfect macOS tool for personalized mass messaging via iMessage/SMS, WhatsApp, Facebook Messenger, Telegram, Viber, and Skype.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
SuperDMs - SuperDMs helps you grow your following by sending bulk DMs to your tweet responders.
Twilio Flex - The programmable contact center platform 📱
Promote Route - A Better WhatsApp™ Experience
Drift - A messaging app that helps you grow your business.