Inter-App Audio

Inter-App Audio (IAA) is a deprecated technology developed by Apple Inc. which routes audio and MIDI signals between applications on the iOS mobile operating system. The technology was first introduced in 2013 in iOS 7 and deprecated in 2019 with the release of iOS 13.

Scope
Inter-App Audio is a host-plugin technology. An IAA host application connects to a node application to send and receive audio, MIDI, timeline information, and other signals.

Node applications
Node applications can be of the following types:
 * Instruments (can receive MIDI signals and produce audio signals)
 * Generators (can produce audio signals)
 * Effects (can receive, transform and send back audio signals)

Limitations
At the moment, audio signal routing is only possible with a sampling rate of 44 1 Hz.

Deprecation
Inter-App Audio was deprecated in 2019 with the release of iOS 13 in favor of the third version of Audio Units.

Competing technologies

 * Audiobus
 * Audio Units
 * Ableton Link