At Apple’s Worldwide Developer Conference (WWDC) on Monday, executives unveiled the much-anticipated Project Catalyst, a new platform that allows developers to more easily bring their iOS apps developed for the iPad over to Macs. (Note: This article about Project Catalyst is available as a free PDF download.)

Project Catalyst—formerly code-named Project Marzipan—makes it easier for iOS developers who want to bring their apps to more than 100 million active Mac users with the latest version of macOS, Catalina. With Catalyst, development team can build one app that can span from iPhone to iPad to Mac, Craig Federighi, Apple’s senior vice president of software engineering, said during the keynote. This opens up more possibilities for integrated app support across the Apple ecosystem.

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Before Catalyst, iOS apps could not run on a Mac or vice versa due to differences in their underlying frameworks, our sister site CNET noted: iOS relied only on UIKit, while macOS used AppKit. The new platform introduces elements of UIKit to macOS Catalina, making it possible for iOS apps to run on Macs.

“It’s really important, because what it’s allowing folks to do is write once and deliver on most Apple devices,” Ray Wang, principal analyst and founder of Constellation Research, told TechRepublic. “This is going to be the future. If you’ve always wanted to get to 10 million MacBook users and you’re an iOS developer, you couldn’t before.”

Apple made it clear that it was not merging the code base for macOS and iOS, but it is allowing developers to work across all platforms.

Project Catalyst is available now with the beta version of macOS Catalina. iOS developers can get started creating Mac versions of their apps by simply checking a box in Xcode—the macOS development environment—to automatically create fundamental features such as cursor controls or password autofill, executives said during the keynote. The app can then be customized to improve the experience on Mac, but most of the conversion work is done by Xcode already.

Twitter and Atlassian both have upcoming Catalyst-built app for macOS, Apple announced.

“Developers should pay attention to Project Catalyst because it’s another step in optimizing developer activities across an ever-increasing set of devices to build experiences on,” Michael Facemire, vice president and principal analyst at Forrester, told TechRepublic. “Catalyst elicits thoughts of recent web innovations around Progressive Web Apps; build an experience for one channel (mobile) and with some amount of conditional logic, have it run on desktop as well.”

The early challenge for Catalyst will be that it is built only for the Apple ecosystem, Facemire said.

“Now iOS developers can port their apps to run on Macs, Android apps can run on ChromeOS, but what about Windows?” he added. “If a company truly wants to support a cross-channel ecosystem, across both major mobile platforms and all three desktop platforms, building natively will still leave a gap.”

It’s likely that Catalyst will spawn similar projects, Wang said.

“You’re going to see more and more of this happen in Xcode,” Wang said. “It’s going to allow you to get to more Apple devices much more easily. If you’re going to learn something, this is the big thing that allows you to get to almost all the future devices for Apple.”

MacOS Catalina will be generally available in fall 2019. While developers can access the beta version now, it will still take some time before apps created with Catalyst begin to show up in the Mac App Store, as developers will need to work on updating existing apps or developing new apps, CNET noted.

For more, check out WWDC 2019: Mac Pro, iPadOS, iOS 13, WatchOS 6, and everything Apple announced on ZDNet.