A software development kit (SDK or devkit) is typically a set of software development tools that allows the creation of applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar development platform. To enrich applications with advanced functionalities, advertisements, push notifications, and more, most app developers implement specific software development kits. Some SDKs are critical for developing a platform-specific app. For example, the development of an Android app on Java platform requires a Java Development Kit, for iOS apps the iOS SDK, and for Universal Windows Platform the .NET Framework SDK. There are also SDKs that are installed in apps to provide analytics and data about application activity; prominent creators of these types of SDKs include Google, InMobi, and Facebook.