iPad Apps Are Coming to the Mac With Apple's Project Catalyst

While the Mac and iPad remain distinct products, Apple continues to bridge the gap between its desktop and mobile platforms. In 2014, for example, it introduced Continuity features like Handoff and Universal Clipboard that enable more seamless experiences across the Mac, ‌iPad‌, and other Apple devices.

The next step in this process is Project Catalyst, which makes it much easier for developers to extend iPad apps to the Mac.

project catalyst
Starting with macOS Catalina and Xcode 11, developers can create a Mac version of an ‌iPad‌ app using UIKit, an Apple framework that until now was intended solely for iOS apps. Adding macOS support to an ‌iPad‌ app is as easy as opening an Xcode project and clicking the Mac checkbox under General > Deployment Info.

While the Mac version of the app should run after the box is checked, this is not always the case, as the Xcode project may contain code that no longer compiles due to frameworks, APIs, or embeddable content that is incompatible with the Mac, according to Apple's developer documentation:

Most ‌iPad‌ apps are great candidates for adaptation, but a few rely on ‌iPad‌ features that don’t exist on a Mac. For example, if your app's essential features require ‌iPad‌ capabilities like gyroscope, accelerometer, or rear camera, iOS frameworks like HealthKit or ARKit, or the app's main function is something like navigation, it might not be suited for the Mac.

Apple has instructions on how to remedy these compatibility issues.

‌iPad‌ apps ported to macOS run natively on the Mac, utilizing the same frameworks, resources, and runtime environment as traditional Mac apps, according to Apple's developer documentation:

The Mac version of your ‌iPad‌ app supports many system features found in macOS without requiring any effort from you…

- A default menu bar for your app.
- Support for trackpad, mouse, and keyboard input.
- Support for window resizing and full-screen display.
- Mac-style scroll bars.
- Copy-and-paste support.
- Drag-and-drop support.
- Support for system Touch Bar controls.

Apple's updated Human Interface Guidelines are a helpful resource for designing and coding the ideal ‌iPad‌ app for Mac.

dc universe project catalyst

DC Universe is an example of a Project Catalyst app coming to Mac

If this all sounds familiar, it is because Project Catalyst is Apple's public-facing name for this initiative, which has been referred to by its internal name of Marzipan until now. Apple's plans to allow iOS apps to easily run on Mac were first reported by Bloomberg's Mark Gurman over 18 months ago.

Apple provided us with a first glimpse of Project Catalyst when it brought the ‌iPad‌ versions of its Apple News, Home, Stocks, and Voice Memos apps to the Mac last year in macOS Mojave. Third-party developers are now able to follow suit in macOS Catalina, which will be released to the public in the fall.

Related Forum: macOS Catalina (10.15)

Top Rated Comments

CE3 Avatar
25 months ago
This should be a big revival for the Mac App Store. Lots of popular apps coming soon.
Score: 17 Votes (Like | Disagree)
bladerunner2000 Avatar
25 months ago
So finally being able to post to Instagram from a desktop computer.
Score: 10 Votes (Like | Disagree)
SeattleMoose Avatar
25 months ago
I like this trend. More choice is always good.
Score: 9 Votes (Like | Disagree)
Razeus Avatar
25 months ago
There's nothing you can say that will get me not to believe Apple isn't going to switch to ARM.
Score: 7 Votes (Like | Disagree)
Jared Strike Avatar
25 months ago
This should also bring over a great deal of productivity apps to the Mac. Win win.
Score: 6 Votes (Like | Disagree)
Krevnik Avatar
25 months ago
Slightly confused. This article says ipad app -> macos. Does that include ios -> macos cause ipad has a different os now.
iPadOS, iOS, tvOS are all still "iOS". The difference is what "Idiom" the platform uses: Phone, Pad, or TV. That changes some of the UI behavior. Pad supports split screen, and uses a UISplitView differently than Phone. TV does some things differently as well.

But I can write one app against UIKit and reuse even UI elements between all three platforms, because it is all UIKit.

Catalyst is UIKit for macOS. Nothing more, nothing less. But it looks like macOS is using the Pad idiom.

Will these "Catalyst" built apps require Catalina? Anyone know.
Yes. Catalyst (UIKit) was private in Mojave, and since Catalina is the first major version with UIKit as a public framework, it will require it.

So, is this anything like Universal Apps in Windows? I vaguely remember there being some derision over this.

I'm not a developer, so from the user perspective I think this could be good, especially if they don't force a dumb down of apps for Mac (which based on the Keynote they aren't).

I guess iOS being based on OSX is finally beginning to fulfill its potential after 12 years.
It is like Universal Apps, but there's a key difference between Apple's approach and Microsoft's. Microsoft built UWP on top of WinRT (edit: the framework, not Windows RT, the SKU) that was part of Win8. These are "Modern" or "Metro" apps. The fact that you had to completely port an app to it to get the benefit made it expensive for established apps like Photoshop. And because of how WinRT worked, you may not even get all the benefit of it since there were some weird issues around WinRT in C++ that I don't know if they resolved in the Win 10 timeframe.

Apple played a longer game. iOS/tvOS/iPadOS and macOS already share a lot of frameworks: Foundation, AVFoundation, Core Data, Core Graphics, Core Animation, Map Kit, etc, etc etc. Before Catalyst, I could still write up an app with a single codebase that compiled for all 4 platforms, mostly. The problem is that AppKit and UIKit are different enough that you have to "fork" a piece of your code for AppKit and one for UIKit. This makes managing things a bit trickier and just more effort. By bringing UIKit to the Mac, what Apple is doing is saying to the (more numerous) iOS devs: "You can now bring your app to the Mac without having to deal with AppKit to do it".

The advantage here is that UIKit is something people already use. iOS has the larger developer base. It's now less of a "semi-port" and now a "tweak it for Mac like you do for tvOS or iPad" situation. That's important.

But, in many ways, because the two have shared most of their core frameworks for years, it was also a lot less work to get here. I think Apple was hoping that only having AppKit/UIKit diverged was enough to entice more devs, but I guess not quite.
Score: 5 Votes (Like | Disagree)

Top Stories

apple watch ecg

Apple Watch Likely to Gain Blood Pressure, Blood Glucose, and Blood Alcohol Monitoring

Monday May 3, 2021 4:03 am PDT by
The Apple Watch may gain the ability to measure blood pressure, blood glucose, and blood alcohol levels, according to newly-revealed information about one of Apple's chosen business partners. Apple has been revealed to be the largest customer of the British electronics start-up Rockley Photonics, The Telegraph reports. Rockley Photonics has developed non-invasive optical sensors for...
airtags teardown tile mat galaxy smarttag

iFixit Shares AirTag Teardown Revealing 'Impressively Compact' Design Compared to Tile Mate and Galaxy SmartTag

Sunday May 2, 2021 4:54 am PDT by
iFixit has shared the first of its two-part series in tearing down Apple's AirTag item tracker, revealing that Apple had to make impressive design decisions to achieve its small design, including rethinking the speaker layout. For comparison, iFixit compared Apple's AirTag to the Tile Mate and the Samsung Galaxy SmartTag. Compared to the competition, AirTag is the smallest in size, with the...
facebook instargram updated att prompt 1

Facebook and Instagram Ask Users to Enable App Tracking in Order to Keep Services 'Free of Charge'

Sunday May 2, 2021 1:22 pm PDT by
As a way to convince users to enable tracking across other apps and websites, Facebook is deploying the tactic of telling users that they must enable tracking as part of the App Tracking Transparency framework in iOS 14.5 if they want to help keep Facebook and Instagram "free of charge." App Tracking Transparency or ATT is the newest privacy feature to come to iPhone and iPad devices as part ...
Flat 2021 MacBook Pro Mockup Feature 1

Mini-LED Display Production Improving for Redesigned MacBook Pro Models Later This Year

Monday May 3, 2021 8:33 am PDT by
Apple supplier TSMT, a key vendor involved in the production of mini-LED displays in the newly announced 12.9-inch iPad Pro, has been able to address technical challenges for the production of mini-LED displays to be used in the upcoming 14 and 16-inch redesigned MacBook Pro models. As reported by DigiTimes, TSMT had initially been facing production constraints with the circuit board and...
Foldable iPhone 2023 Feature Yellow

Kuo: Apple to Launch 8-Inch Foldable iPhone in 2023

Sunday May 2, 2021 8:43 pm PDT by
Apple is working to launch a foldable iPhone with an 8-inch QHD+ flexible OLED display in 2023, Apple analyst Ming-Chi Kuo said today in a note to investors that was seen by MacRumors. Based on our latest industry survey, we forecast that Apple will likely launch a foldable iPhone with an 8-inch QHD+ flexible OLED display in 2023, with SDC as the exclusive display supplier and Samsung Foundry...
iOS 14 on iPhone feature emergency

Apple Releases iOS and iPadOS 14.5.1 With Fixes for App Tracking Transparency Bug, WebKit Security Issues

Monday May 3, 2021 10:04 am PDT by
Apple today released iOS and iPadOS 14.5.1, minor security updates that come just a week after the release of the iOS 14.5 update. There is also a companion watchOS 7.4.1 update for Apple Watch and an iOS 12.5.3 update for older iPhone and iPad devices that don't support Apple's latest operating system versions. According to Apple's release notes, the update fixes a bug with App Tracking...
General Music and AirPod 3 Feature

Rumor: Apple to Announce Third-Generation AirPods and HiFi Apple Music Tier in 'Coming Weeks'

Saturday May 1, 2021 3:57 am PDT by
Citing sources within the music industry, Hits Double Daily reports that Apple is preparing to launch a new HiFi Apple Music tier in the "coming weeks," which will come alongside the release of the rumored third-generation AirPods. According to the report, the new tier, which will offer high-fidelity music streaming, will cost the same $9.99 monthly subscription as the current individual...
Top Stories 58 Feature 1

Top Stories: iOS 14.5 Released, AirTag Launch, New iMac and iPad Pro Pre-Orders

Saturday May 1, 2021 6:00 am PDT by
After nearly three months of beta testing, Apple this week finally released iOS 14.5, the company's biggest update since the iOS 14 launch last September. One of the main new features included in the update is support for AirTags, Apple's item trackers that also finally became available this week some two years after their existence first leaked. Apple this week also began taking orders for...
tile sticker e1570533758981

Tile CEO: 'We Welcome Competition From Apple, But We Think It Needs to Be Fair'

Tuesday May 4, 2021 9:51 am PDT by
Just after Apple announced its AirTags, Tile CEO CJ Prober relayed his concerns about competing with Apple in the tracking space, and said that Tile would ask Congress to investigate Apple's business practices specific to Find My and item trackers. Prober this week did an interview with Bloomberg, where he further expanded on Tile's complaints about Apple and why he feels that Tile is...
apple music album cover art

iOS 14.6 Beta 1 Code Hints at Upcoming HiFi Apple Music Support

Saturday May 1, 2021 10:41 am PDT by
Apple is laying the groundwork for adding HiFi support to Apple Music which would offer Apple Music subscribers and owners of compatible devices, such as certain models of AirPods, access to high-fidelity audio streaming, according to code within the iOS 14.6 beta discovered by MacRumors. Earlier today, a report claimed that Apple will announce a new $9.99 per month Apple Music tier that...