The App Store is a digital distribution platform, developed and maintained by Apple Inc., for mobile apps on its iOS and iPadOS operating systems. The store allows users to browse and download apps developed with Apple's iOS Software Development Kit. Apps can be downloaded on the iPhone smartphone, the iPod Touch handheld computer, or the iPad tablet computer, 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 was 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 that do not function as intended or that do not follow current app guidelines. As of 2020, the store features around 1.8 million apps. While Apple touts the role of the App Store in creating new jobs in the "app economy" and claims to have paid over $155 billion to developers, the App Store has also attracted criticism from developers and government regulators that it operates a monopoly and that Apple's 30% cut of revenues from the store is excessive.