IOS SDK in the context of Apple Developer

The App Store is an app marketplace developed and maintained by Apple, for mobile apps on its iOS and iPadOS operating systems. The store allows users to browse and download approved apps developed within Apple's iOS SDK. Apps can be downloaded on the iPhone, iPod Touch, or iPad, and some can be transferred to the Apple Watch smartwatch or 4th-generation or newer Apple TVs as extensions of iPhone apps.

The App Store opened on July 10, 2008, with an initial 500 applications available. The number of apps peaked at around 2.2 million in 2017, but declined slightly over the next few years as Apple began a process to remove old or 32-bit apps. As of 2024, the store features more than 1.9 million apps.

A software development kit (SDK) is a collection of software development tools in one installable package to develop a software. They facilitate the creation of applications by having a compiler, debugger and sometimes a software framework. They are normally specific to a hardware platform and operating system combination. To create applications with advanced functionalities such as advertisements, push notifications, etc., most application software developers use specific software development kits.

Some SDKs are required for developing a platform-specific app. For example, the development of an Android app on the Java platform requires a Java Development Kit. For iOS applications (apps) the iOS SDK is required. For Universal Windows Platform the .NET Framework SDK might be used. There are also SDKs that add additional features and can be installed in apps to provide analytics, data about application activity, and monetization options. Some prominent creators of these types of SDKs include Google, Smaato, InMobi, and Facebook.