Twilio - Brings voice and messaging to your web and mobile applications.
Ring4 Meeting - Dead simple video conferencing - free, in browser
Plivo - Plivo simplifies your customer engagement.
Fellow.app - A manager’s co-pilot for 1:1s, meetings, feedback & goals 🚀
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Everleagues - Everleagues is a cloud-based application that offers team communication, file sharing and storage, data tracking, and activities management.