The Sinch SDK allows developers to add voice calling and/or instant messaging to their web apps. It handles signaling and audio management and also provides the ability to create user interfaces. This first release supports only instant messaging and app-to-phone calling with app-to-app calling to be added at a later date.
Call Loop, web-based voice and SMS solution provider, offers the Call Loop API that allows developers to add Call Loop’s calling and SMS features to third party apps. Often referred to as the “Constant Contact” for voice and text, Call Loop focuses on broadcast communications. Businesses or individuals can reach subscriber bases via voice or text messages.