Melrose Labs SMSC Simulator - SMPP SMSC simulator to test SMS messaging applications.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Twilio - Brings voice and messaging to your web and mobile applications.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs