The Sinch SDK for iOS lets developers add voice calling and instant messaging capabilities to their iOS based mobile apps. The SDK handles signaling and audio management. In addition it offers support for:
App to app calling
App to phone calling
Instant messaging to single and multiple recipient
Businesses are taking advantage of the ubiquity of mobile devices and SMS. This tutorial describes how to send an SMS message to a phone with PHP using the Twilio API. Twilio provides numerous communications services, including the ability to make and receive phone calls through the browser, mobile or desktop, send and receive SMS and MMS messages, and handle short codes.