Dialpad - Switch is a cloud-based phone system built for Google Apps users.

Twilio - Brings voice and messaging to your web and mobile applications.

Aircall - Aircall is a call center software of a new generation designed for fast growing companies. Setup instantly and integrates to your CRMs

Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates

Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.

BulkSMS - SMS messaging service provider offering two-way SMS communication services.