iPhone Duo Developer Resources · Unofficial developer resource
Build for iPhone Duo
SwiftUI guides, adaptive layouts, fold handling, multiple displays, Xcode tools, and official Apple resources — all in one place.
Updated for iOS 27.1Xcode 27.1 beta
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01Prepare Your AppMake your existing iPhone app work correctly on Duo.Read guide02SwiftUIAdaptive layouts, size classes, safe areas and ReservedRegion.Read guide03ArrangementViewPlace content with .split and .overlay around the fold.Read guide04ReservedRegionKeep custom chrome clear of system-reserved hinge space.Read guide05Replace UIScreen.mainRead the window scene, not a global screen singleton.Read guide06Fold & PoseBuild layouts that adapt as the device opens and folds.Read guide07Multiple DisplaysBuild experiences across inner and outer displays.Read guide
DuoReady Apps
Is your app DuoReady?
A curated directory of apps that show how they adapt for iPhone Duo — adaptive layouts, fold-aware interfaces, multiple displays, and more. Compatible scaling is not enough; every entry cites evidence.
Browse apps optimized for DuoIs your app ready for iPhone Duo?
Apple's adaptation guidance centers on size classes, window scenes, safe areas, Split View, and avoiding hardcoded assumptions about the display.
View Full Compatibility Checklist- Uses adaptive layouts
- Supports dynamic window resizing
- Avoids UIScreen.main
- Handles asymmetric safe areas
- Works in Split View
- Supports different size classes
- Tests every Duo pose
- Avoids content behind the fold