Asterisk - An open source telephony switching and private branch exchange service for Linux.
Presence - 360 photo and video sharing done right.
Wazo.io - The UCaaS Platform Built for MSPs
Quizizz - Quizizz is a multiplayer quizzing game.
FreeSWITCH - FreeSWITCH is an open-source media application designed to support popular protools such as SIP and WebRTC and provides a platform to develop voice and video applications.
iClassPro - iClassPro is a popular web based class management software for Gymnastics, Cheerleading, Swim, Dance, and other enrollment based businesses.