AirPlay

AirPlay is a proprietary wireless communication protocol stack/suite developed by Apple Inc. that allows the streaming of multimedia and device screens, together with related metadata, between compatible devices. Originally implemented only in Apple's own software and hardware, the company has since licensed the AirPlay protocol stack to third-party manufacturers and it has been implemented on devices such as television sets and home audio systems. AirPlay works through either a direct peer-to-peer connection between devices or through an infrastructure local network.

In 2004, Apple introduced AirTunes as a new feature of iTunes 4.6. It allowed music streaming over a network to an AirPort Express, which was equipped with a 3.5 mm analog-digital audio jack for speakers or other audio devices. In 2010, Apple introduced a new iteration of the AirTunes technology, now called AirPlay, as part of iOS 4.2. It supported audio and now video streaming to the Apple TV, and later added screen-mirroring and eventually support for a broad range of 3rd-party AirPlay-compatible speakers and AV equipment.

Apple announced AirPlay 2 at its annual WWDC conference on June 5, 2017. It was scheduled for release along with iOS 11 in the third quarter of 2017, but was delayed until June 2018. Compared to the original version, AirPlay 2 improves buffering; adds streaming audio to stereo pairs of speakers (e.g. stereo pairs of individual HomePods; AirPlay and its predecessor, AirTunes have always been stereo); allows audio to be sent to multiple devices in different rooms; and control by Control Center, the Home app, or Siri, functionality that was only available previously using iTunes under macOS or Windows.

AirPlay sender devices include computers running iTunes, and iOS devices such as iPhones, iPods, and iPads running iOS 4.2 or greater, and devices can send AirPlay over Wi-Fi or ethernet. OS X Mountain Lion supports display mirroring via AirPlay on systems containing 2nd generation Intel Core processors or later.

In 2016, HTC released the "10", also known as "One M10", an Android phone with Apple AirPlay streaming.

As of iOS 4.3, third-party apps like ApowerMirror, AirServer, and Reflector may send compatible audio and video streams over AirPlay. The iTunes Remote app on iOS can be used to control media playback and select AirPlay streaming receivers for iTunes running on a Mac or PC.

As of macOS 10.14, there is no public API for third-party developers to integrate AirPlay 2 into their macOS apps. However, there are third-party streamers such as Airfoil. In May 2019, a third-party developer released a macOS app that can stream audio using AirPlay 2. The app includes a helper tool called "AirPlay Enabler" that uses code injection to bypass restrictions to the AirPlay 2 private API on macOS.

AirPlay receiver devices include Apple TV, HomePod, third-party speakers and the discontinued AirPort Express, which included a combined analog and optical S/PDIF audio output connector. Compatible devices can receive AirPlay over wi-fi or ethernet. Some open-source projects have reverse-engineered the audio part of the protocol, enabling any computer to be turned into an AirPlay receiver for audio.