Use a spare iPhone or iPad as a real second monitor

Made by peetzweg/

A free alternative to Apple’s Sidecar and to paid tools like Duet and Luna, turning an iPhone, iPad or spare Mac into a genuine extended display rather than a mirror — macOS treats it as a real second monitor you can drag windows onto and position in system settings.

It connects over the USB cable for the lowest lag, using the same transport macOS already has for iOS devices, or over WiFi with no configuration by advertising itself on the local network. The display matches the device panel pixel for pixel, and touch and two-finger scroll work as input.

Can I use this?

Mac app

You'll need A Mac plus an iPhone, iPad or second Mac · Setup needed

Worth knowing It is macOS-only on the host side, and the project is candid that it exists because every existing option has a catch rather than because this one has none. Wireless use inherits whatever your network is doing, which is why the project recommends the cable. Apple Pencil support is on the roadmap rather than in the app. GPL-3.0, which constrains how the code can be reused in closed products. BuildTube has not run or verified this software.

Why it's here

Not trending this week

Last seen on the GitHub trending list on 20 September 2026. It stays on BuildTube so you can still find it.

5,106 people have starred it on GitHub.

Numbers checked on 6 October 2026; not refreshed since.

Behind it

See the code on GitHub

BuildTube has not run or verified this project. Everything above is written from what the creator published.

Made this?