Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
KrispCall - Virtual cloud phone system for business
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
CallHippo - Easy to use Phone System with World-Class Support
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs