OpenDisplay

OpenDisplay allows developers and Mac users to extend their display by using an iPhone, iPad, or spare Mac as a second monitor over USB or WiFi connection. The tool works as a pair of applications: a Sender installed on the Mac to capture and stream the virtual display, and a Receiver app installed on the device that will function as the additional screen. It provides a true extended display rather than mirroring, with Retina-sharp quality, low latency, and support for touch and scroll input.

OpenDisplay is developed by peetzweg and released under the GPL 3.0 license. The software is free to use with no subscription required, no dongle needed, and no account registration necessary. It is presented as an open-source alternative to Apple's Sidecar and other commercial display extension solutions. The tool supports macOS 14 and later on the sender side, with receiver compatibility for iPadOS 15 and later, iOS 15 and later, and macOS 12 and later for older Macs being repurposed as displays.