Shared UI is the siren song of cross platform. It has its uses (POC apps, short-lived apps, LOB apps), but it should not be the general go to for anyone. Yet in

Shared UI is the siren song of cross platform. It has its uses (POC apps, short-lived apps, LOB apps), but it should not be the general go to for anyone. Yet inexperienced teams are going after that as their first foray into cross platform for large, production apps and paying the price. Experienced cross platform devs generally go for what you describe, a shared core with platform specific UI. In phase 1 you have 50%-70% of code sharing, and over time as you develop a UI DSL you can move up to 90% of code into the shared layer. The tools for this exist today mostly by leveraging existing mechanisms for C FFI. In the old days that meant writing C++, but theres much better options today in Xamarin and (soon) Kotlin Native. Xamarin is very much batteries included, and you can leverage most of the C# nuget ecosystem to get the functionality you desire.