OpenDisplay Receiver

About

OpenDisplay Receiver is the receiver half of OpenDisplay, a free and open-source app that lets you use another device as an extended display for your Mac, described as a free, open-source alternative to Apple Sidecar, Duet Display and Luna Display. The Receiver runs on iPhone and iPad (iOS/iPadOS 15+), on Android phones and tablets (Android 7.0+, in public beta, over WiFi), and on a spare Mac running macOS 12+, which the site says lets older Macs serve as the display. A Linux receiver is also in beta. Connections can be made over USB or WiFi, and the site describes the display as a true extended display rather than a mirror, with Retina-sharp output and touch and scroll support.

OpenDisplay is two apps that work together: the Sender runs on the computer whose desktop you want to extend, and the Receiver runs on the device used as the extra screen. The site states there is no subscription, no dongle and no account required, and that the project is licensed under GPL-3.0. The iOS receiver is available via TestFlight beta or source compilation, and the Android version is in beta through a Google Group tester program followed by Google Play installation.

OpenDisplay is developed by one person, Philip Poloczek, and is funded through voluntary support on Ko-fi to cover the Apple Developer membership and domain costs. The site also lists press coverage and user posts praising the app's approach.