We all know how to build websites and many of us build APIs as well. In short, interacting with users through browsers and HTTP is old hat. Applications reach out to users through their phones, making calls, sending text messages, and driving more engagement even when your users may not be in front of a computer or using a browser. Making PHP scripts that can make a phone ring or buzz is easier than you might think. Learn how to make your application interact with phones in this talk.