Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Conversations.im - XMPP client designed with ease of use and security in mind
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Telegram X - Meet Telegram X for iOS and Android – two new official apps that offer more speed, longer batter life and smooth animations.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs