Twilio - Brings voice and messaging to your web and mobile applications.
TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Dingtone - Dingtone is a free call and texting application for making unlimited calls and text messages to any number at the moment registered in any part of the world by any cellular company.
CallHippo - Easy to use Phone System with World-Class Support
TextMe - TextMe is a free calls and messaging application at both local and international levels.