I'm working on an app builder on iOS. This prototype's main feature is that it uses real iOS Swift code as the "source of truth" for the editor. The current prototype linked mainly demonstrates a proof of concept that it is possible to dynamically generate any SwiftUI view at runtime and run it in a UIWindow. Eventually this will be integrated as part of a real iOS project's build system to automate a lot of the development process.
Link: TestFlight - Apple