Appercode project, UI framework based on Xamarin platform, which allows creation of user interface for cross-platform mobile applications using single XAML markup. In addition, working on mobile applications targeted for iOS, Android and Windows Phone and developed on Xamarin, Appercode and Windows platforms. * Made low-level optimizations in the Appercode framework core. Achieved increasing of applications performance and allowed to scroll list of thousands of elements with complex content without visible lags. * Remade caching subsystem, removed delays while loading of application content from external service. * Did code reviews, debugging and profiling to investigate sources of applications performance issues.