DirectX is a collection of application programming interfaces (APIs) developed by Microsoft for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. It is a part of the Microsoft Windows operating system, and is also available for the Xbox video game consoles and as a software development kit (SDK) for Windows.
DirectX is used by game developers to create high-performance multimedia applications, and is also used by other software developers to create multimedia applications that can take advantage of hardware acceleration.