Bitrig now lets you build and test apps for Apple’s upcoming foldable right inside its AI coding platform, with a 3D simulator you can fold, tilt, and rotate like the real phone.
The update arrived on September 19, just a week after Apple released Xcode 27.1 beta 1 with iPhone Duo support. Bitrig detailed the changes on its official blog.
What Bitrig’s 3D simulator does
Standard iPhone simulators show a flat device. Bitrig’s take is interactive. You can grab the virtual iPhone Duo, fold it closed, open it flat, leave it half-folded, turn it around, and set it down in different poses. Your app responds in real time as you move it.
That matters because Duo has more than one way to be used. Bitrig says the phone can sit like a laptop on a table, stand like a tent on a nightstand, or work folded shut on its outer display. Developers need to see how layouts break in each position.
How developers can use the new Duo features
Bitrig points to four specific SwiftUI tools Apple introduced for the foldable:
- Try every pose. Test open, closed, and partially folded in both portrait and landscape. The 3D view lets you drag and rotate to check adaptive layouts.
- Respond to the hinge. Use
onHingeChangeto trigger animations as the phone folds, like Apple’s window-like unfold effect on the outer display. Bitrig streams live hinge data as you fold. - Build hands-free experiences. Use
ArrangementViewto put video on the top half and controls on the bottom when Duo is propped on a table. Bitrig also reminds developers to support landscape for outer-display use. - Use both displays at once. Add
CameraCaptureAccessoryto show useful content on the outer screen while the inner screen handles the main camera view.
For most native SwiftUI apps, Bitrig says standard navigation and toolbars already adapt to Duo, but the new APIs help take advantage of the extra space.
From vibe-coding app to full Xcode workflow
Bitrig started in 2025 as an iPhone app that turned text or voice prompts into SwiftUI apps running inside Bitrig itself. Since then it added a Mac app with full Xcode toolchain access, an integrated simulator, on-device testing, and export to Xcode or TestFlight and the App Store.
With this Duo update, Bitrig also helps manage multiple Xcode versions. You can build against the Xcode 27.1 beta to prepare a Duo-ready app and switch back to Xcode 27 for regular updates.
Apple’s iPhone Duo doesn’t ship until October 23, with preorders starting October 16 and pricing from $1,999, but the developer tools are already live. Bitrig is also hosting a Bitrig Hacks: iPhone Duo Edition meetup in San Francisco on September 26 to get developers experimenting early.
If you’re curious what the hardware actually offers, Apple’s first foldable packs a 7.6-inch inner OLED and a 5.4-inch outer display with an A20 Pro chip and the same A20 Pro driving the iPhone 18 Pro lineup.
