WhatsMany - Send personalised WhatsApp messages in bulk
Amio Messaging SDK - Develop for multiple messengers using JavaScript
LoopMessage - LoopMessage is a perfect macOS tool for personalized mass messaging via iMessage/SMS, WhatsApp, Facebook Messenger, Telegram, Viber, and Skype.
Notif.me SDK - A Node.js lib to send all your transactional notifications
Porterhouse - Send mass iMessage and SMS texts from your existing number with a single click!
Postman for Mac (Beta) - Build, test, and document your APIs faster