There's not a consistent story but there are a bunch of options, principally divided into wrappers around existing libraries (SwiftGTK [1], Qlift [2], LVGLSwift

There's not a consistent story but there are a bunch of options, principally divided into wrappers around existing libraries (SwiftGTK [1], Qlift [2], LVGLSwift [3]) and SwiftUI workalikes (Tokamak [4], SwiftCrossUI [5], AdwaitaSwit [6], there are others too). After exploring most of these for my use case (something that needs to run on an "embedded" RPi CM4 as well as iOS), I wrote a Swift bridge/runner for Flutter [7] which is working well. That enables me to write the UI in Dart and the business logic in Swift. I looked at all the other options below (that's how I know about them, indeed [3] I wrote as part of my research), in the end I felt that none of them were at the time of investigating sufficiently mature to base a product around. [1] https://github.com/rhx/SwiftGtk https://github.com/rhx/SwiftGtk [2] https://github.com/Longhanks/qlift https://github.com/Longhanks/qlift [3] https://github.com/PADL/LVGLSwift https://github.com/PADL/LVGLSwift [4] https://github.com/TokamakUI/Tokamak https://github.com/TokamakUI/Tokamak [5] https://github.com/stackotter/swift-cross-ui https://github.com/stackotter/swift-cross-ui [6] https://github.com/AparokshaUI/adwaita-swift https://github.com/AparokshaUI/adwaita-swift [7] https://github.com/PADL/FlutterSwift https://github.com/PADL/FlutterSwift