PhoneGap is an open source framework that allows developers to build mobile apps using HTML, CSS and JavaScript. It works by taking these files and compiling them into apps that can run across multiple platforms such as iOS, Android, Windows and Blackberry. Developers upload their code to the Adobe PhoneGap Build cloud service, which generates apps for different devices. This allows apps to be created more quickly and easily across platforms. While testing on Android is simple, Apple testing requires an additional development certificate.