AirTunes

AirTunes was Apple's audio-only wireless streaming protocol that enabled iTunes to send music to speakers connected to an AirPort Express over a local Wi-Fi network. It was part of Apple's AirPort ecosystem and allowed users to play the contents of their iTunes library on remote speakers throughout a home.

AirTunes was introduced in the mid-2000s alongside AirPort Express hardware. The feature let users select an AirPort Express receiver in iTunes to output audio via the connected speakers, effectively creating a wireless speaker zone. It was primarily used with iTunes on macOS and Windows.

Technically, AirTunes relied on a discovery and control mechanism using Apple’s Bonjour protocol to locate AirPort Express devices on the network. iTunes streamed encoded audio data to the receiver, which played it through the device’s analog or digital audio outputs. The streaming protocol itself was proprietary to Apple. In later years, third-party projects reverse-engineered the protocol, enabling non-Apple receivers to act as AirTunes endpoints.

Legacy and transition: In 2010, Apple introduced AirPlay, a broader wireless streaming technology that covered audio, video, and later screen mirroring. AirTunes functionality was subsumed under AirPlay, and support for AirPlay on AirPort Express devices continued for some years before hardware was discontinued. Today, AirPlay serves as the family of technologies that superseded AirTunes for wireless audio streaming.

See also: AirPlay, AirPort Express, Shairport.