Yac - Take your time back from Zoom & Slack
NextPlane - NextPlane offers cloud-based, scalable unified communications federation service for the enterprise.
Echoes - Voice-first messaging for fast & collaborative remote teams
Voxer - Turn your phone into a Walkie Talkie. Don't waste time on phone calls and voicemails.
WebRTC - WebRTC is a free, open project that enables web browsers with Real-Time Communications (RTC) capabilities via simple JavaScript APIs. The WebRTC components have been optimized to best serve this purpose.
Sameroom - Chat interoperability-as-a-service