Discover how to extend and build upon the components of the Xamarin.Forms toolkit to develop an effective, robust mobile app architecture. Starting with an app built with the basics of the Xamarin.Forms toolkit, you'll go step by step through several advanced topics to create a solution architecture rich with the benefits of good design patterns and best practices. You'll start by introducing a core separation between the app's user interface and its business logic by applying the MVVM pattern and data-binding. Then you focus on building out a layer of plugin-like services that handle platform-specific utilities such as navigation and geo-location, and on how to loosely use these services in the app with inversion of control and dependency injection. Next you connect the app to a live web-based API and set up offline synchronization. Then, you delve into testing the app logic through unit tests. Finally, you set up Visual Studio App Center for monitoring usage and bugs to gain a proactive edge on app quality.