iOS, originally known as iPhone OS, is a mobile operating system developed by Apple exclusively for its smartphones. It debuted in January 2007 with the first-generation iPhone, which launched in June 2007.

iOS powers many of Apple’s mobile devices, including the iPhone. It was also used on iPads until the introduction of iPadOS in 2019, and on iPod Touch devices until their discontinuation in mid-2022. As the world’s second-most widely installed mobile operating system after Android, iOS serves as the foundation for Apple’s other operating systems: iPadOS, tvOS, and watchOS.