At WWDC last year, Apple shared a glimpse at the future of macOS. With their “Sneak Peek” of a framework, codenamed Marzipan, they previewed how macOS could support iOS apps in the future.
In macOS Mojave, Apple included a small set of “marzipan” apps – News, Stocks, Voice Memos, and Home – but the thing most people want to see is their favorite iOS apps on the Mac. Thanks to iOS developer Steve Troughton-Smith, we’ve started to get a pretty interesting idea.
In a tweet posted yesterday, Steve shared screenshots of the podcast app “Overcast” running on a Mac.
Marco very kindly let me marzipanify @OvercastFM and rob him of the chance to be the first person to see Overcast running on the Mac; thank you @marcoarment ? Even on Mojave, at this early stage, this makes me incredibly excited for WWDC pic.twitter.com/jZbP5CyndL
— Steve Troughton-Smith (@stroughtonsmith) May 1, 2019

Screenshot: Steven Troughton-Smith
Based on the images in the tweet, it appears that the port of Overcast is the full-featured version, complete with dark mode, playback, chapters, sleep timer, and sharing.

Screenshot: Steve Troughton-Smith
He even went beyond the basic proof of concept, and did some additional design work, adding in a third column to the layout.
I couldn’t wait for @marcoarment to redesign his UI, so I hacked up Overcast to use a three-column view on the Mac… ? Looks kinda nice already! All done without source code access pic.twitter.com/4ZgY0hzbRl
— Steve Troughton-Smith (@stroughtonsmith) May 2, 2019
Steve Troughton-Smith has been hammering away at the framework for Marzipan since Apple demonstrated it last year. Since then, he’s shown various Apple apps, some of his own apps, and other third-party apps running on the Mac. He has also developed a tool for making it easier for developers to experiment with their iOS apps on the Mac.
According to recent rumors, there’s a strong likelihood that Apple will release a developer-accessible version of Marzipan this year at WWDC. Rumors also suggest that shipping macOS versions of iOS apps may be as simple as checking a box in Xcode.
Troughton-Smith’s tweets show that, while it may be fairly simple to convert iOS apps to Mac apps, developers could also add some platform specific features to make iOS apps more feature-rich or powerful on the Mac.
WWDC 2019 is scheduled to run June 3–7, and it’s expected that Apple will show off tons features and updates to their OSs. If rumors pan out, we’ll start to officially see iOS apps make appearances on the Mac in the fall with iOS 13 and macOS 10.15. Until then, it’s worth following @stroughtonsmith to see just what Apple might be up to behind the scenes.