Alloy provides some additional utility libraries that simplify certain functions, such as animations, string manipultation and display unit conversion. These libraries are referred to as "builtins."

To use a builtin library, require the library name, minus the '.js' extension, with alloy as the root directory in your require call. For example, to use the animation builtin:

var animation = require('alloy/animation');
animation.crossFade(view1, view2, 500, finishCallback);

During the compilation process, Alloy determines which builtins are being used, and adds them to the generated Titanium project.