Ionic is an open-source SDK for developing hybrid mobile apps using web technologies like HTML5, CSS, and JavaScript. It builds on top of AngularJS and Apache Cordova. Ionic provides tools and services to create hybrid apps that can access device capabilities like the camera and contacts through Cordova plugins. Developing with Ionic requires knowledge of HTML/HTML5, CSS/CSS3, JavaScript, and AngularJS. New projects are started using the Ionic CLI, which provides templates for common app types, and platforms can be added to build for iOS or Android.