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Documentation and sample code downloads for Azure.
You can try Azure for free: choose Mobile App and press Next, then get started with one of three pre-built demos: Todo List, Xamarin CRM, or Field Engineer. Azure App Services features are easy to add to Xamarin apps, including cloud data storage and cross-platform push notifications.
Connected Services in Xamarin Studio
The new Connected Services feature of Xamarin Studio helps developers to quickly and easily add Azure functionality to mobile applications from within the IDE. Currently available for testing in the Alpha channel.
Azure App Services
There is a collection of Azure Mobile Apps documentation that guides you through the process of implementing the Azure Mobile Client SDK component. Xamarin also offers an Azure Messaging component to help implement push notifications across platforms.
Active Directory Authentication
Microsoft's Web API exposes a REST-like interface that can be easily consumed by Xamarin applications. You can easily spin-up an Azure Website and build a WebAPI-based app to connect to Xamarin apps.
In addition to the documentation samples, the following complete applications demonstrate various Azure features incorporated into Xamarin apps: