DeskJoin Screen · Comparison

DeskJoin Screen vs Duet Display vs Luna Display.

All three can add another screen, but they solve different problems. Compare DeskJoin Screen's free local approach with a broader subscription service and a hardware-based display system.

The short answer

DeskJoin Screen is the simplest choice when you want a free second display over your local network. A Mac can extend its desktop to another Mac, a Windows PC, an iPhone, an iPad, or an Android device. Windows can also send or receive a mirrored screen. No product account or hardware dongle is required.

Duet Display covers many more devices and workflows, including iPad, iPhone, Android, Windows, remote desktop, and drawing features. Luna Display supports older Macs and iPad workflows through dedicated hardware that stays connected to the primary computer.

DeskJoin Screen for iPhone and iPad is now available on the App Store. An iPhone or iPad running iOS or iPadOS 17 or later can receive an extended display from a Mac over the local network.

A free Duet Display alternative for two Macs

If your goal is simply to use another Mac or MacBook as a second monitor, DeskJoin Screen covers that Mac-to-Mac workflow without a subscription. Install the same app on both Macs, choose Extend or Mirror, and start the connection from the Mac whose desktop you want to expand.

Duet Display remains the broader option when you need remote access, drawing-tablet features, advanced touch workflows, or a wider set of cross-platform features. DeskJoin Screen focuses on free, nearby display sharing with no login.

A Luna Display alternative without a hardware dongle

DeskJoin Screen can turn a Mac into a second display without buying or attaching dedicated hardware. It connects through Wi-Fi, Ethernet, or Thunderbolt Bridge and does not require both Macs to use the same Apple ID.

Luna Display remains the stronger fit for older versions of macOS and for its established iPad workflow. DeskJoin Screen requires macOS 12.3 or later on Macs, but it does not require dedicated display hardware.

Feature comparison

Competitor information was checked against the vendors' official pages on September 18, 2026. DeskJoin iPhone and iPad availability was updated on September 25, 2026. Plans, prices, and compatibility can change.

DeskJoin Screen, Duet Display, and Luna Display comparison
Feature	DeskJoin Screen	Duet Display	Luna Display
Best fit	Free local display sharing between a Mac and nearby Mac, Windows, iPhone, iPad, or Android devices	Mixed Mac, Windows, iPad, iPhone, and Android workflows	Mac or Windows to a second Mac or iPad
Cost model	Free	Subscription; Duet Air is listed from US$3.99/month	One-time Luna hardware purchase
Extra hardware	None	None	Luna USB-C or HDMI hardware is required
Product account	Not required	Required on both computers	No account step in the standard setup; Luna hardware is required
Mac-to-Mac extended display	Yes	Yes	Yes
Mirror another Mac	Yes	Yes	Focused on second-display modes; features vary by setup
Extend receivers	Mac, Windows, iPhone, iPad, and Android; Extend is initiated from a Mac	Mac, Windows, iPad, iPhone, and Android, depending on the setup and plan	Mac or iPad
Connections	Wi-Fi, Ethernet, or Thunderbolt Bridge	Wireless or wired; local and remote features depend on plan	Wi-Fi, USB, Ethernet, or Thunderbolt
Mac requirements	Both Macs need macOS 12.3 or later	Current Mac app supports macOS 12.3+; legacy downloads are available	Mac-to-Mac supports macOS 10.13+; USB requires macOS 10.15+
iPad support	Yes; available on the App Store for iOS and iPadOS 17 or later	Yes	Yes
Windows support	Yes; sends and receives Mirror, and receives Extend from a Mac	Yes	Yes as a primary computer
Android support	Yes; receives an extended display from a Mac	Yes	No
Local-only design	Yes; no cloud relay or internet required	No; also includes account-based remote workflows	Direct Wi-Fi or wired connections with Luna hardware

Which one should you choose?

Free · Local · Mac, Windows, iPhone, iPad, AndroidChoose DeskJoin ScreenChoose it when you want a free, local second display without an account or dongle. A Mac can extend to another Mac, a Windows PC, an iPhone, an iPad, or an Android device; Windows also supports Mirror sending and receiving.

Cross-platform · SubscriptionChoose Duet DisplayChoose it when you need internet remote desktop, drawing-tablet features, advanced touch workflows, or a broader set of cross-platform features.

Hardware · Older MacsChoose Luna DisplayChoose it when support for older Macs or an iPad matters and you prefer a dedicated hardware-assisted solution with a one-time purchase.

Where DeskJoin Screen is deliberately smaller

DeskJoin Screen does not include internet remote desktop or professional drawing-tablet tools. Windows cannot initiate Extend mode, while Android, iPhone, and iPad currently act as Extend receivers for a Mac.

Its focused purpose is also its advantage: install the free app on compatible nearby devices, keep display traffic on the local connection, and use supported Extend or Mirror workflows without buying a dongle or creating an account.

Official sources

Duet details were checked against theDuet product page,Duet download page, and official Duet pricing shown at the time of review.

Luna details were checked against theLuna Display product page andLuna system requirements.

Duet Display and Luna Display are trademarks of their respective owners and are used here only to identify and compare the products. If a vendor changes a feature or requirement, please email the author so this page can be corrected.

Comparison questions

What is a free Duet Display alternative for two Macs?

DeskJoin Screen is a free Duet Display alternative when you want to use one Mac as a second monitor for another Mac. It needs no additional hardware or product account. It can also use a Windows PC, iPhone, iPad, or Android device as the receiving display for a Mac.

Can I use another Mac as a second monitor without Luna Display hardware?

Yes. DeskJoin Screen needs no hardware dongle. Install the same app on both Macs and connect over Wi-Fi, Ethernet, or Thunderbolt Bridge.

Which option supports the oldest Macs?

Luna Display publishes Mac-to-Mac support for macOS 10.13 or later. DeskJoin Screen requires macOS 12.3 or later on both Macs. Duet offers current and legacy Mac downloads, with requirements depending on the connection and app version.

Which option is best for iPad or Windows?

DeskJoin Screen is a free choice for local workflows: a Mac can extend to an iPad, iPhone, or Windows PC, and Windows can send or receive a mirrored screen. Duet Display has a broader cross-platform and remote feature set. Luna Display supports an iPad or secondary Mac through dedicated hardware and can use a compatible Mac or Windows PC as the primary computer.

Can I use an Android device as a second display for a Mac?

Yes. DeskJoin Screen for Android can receive an extended display from a Mac over the local network. Android cannot initiate its own extended desktop.