RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Twilio Video - Real-time video infrastructure and SDK
JustCall - The Cloud Phone System of choice for modern sales and support teams. We help end clueless conversations by adding context to every call.
Asterisk - An open source telephony switching and private branch exchange service for Linux.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
Grasshopper - Grasshopper enables entrepreneurs to build a virtual office that connects callers to employees, wherever they are.