Cocoa is the native application programming interface of the macOS X operating system. Apps written using the Cocoa API have the distinctive look and feel of Apple software, including the appearance of the windows and menus, and how the application behaves. Cocoa apps are written using Apple's official integrated development environment (IDE), called Xcode.
Cocoa has three major sets of Objective-C libraries, or frameworks, that comprise its main features and functions:
- The Foundation Kit, also known as Foundation, which provides string and value manipulation, containers, iteration, distributed computing, and looping. The Foundation libraries are fundamental tools not related to the graphical user interface (GUI) of OS X.
- The Application Kit, also known as the AppKit, contains all the GUI functions.
- Core Data, the library that provides an aspect of application development known as object persistence.