Last week Microsoft announced CORS support for Office 365 APIs, specifically for Files and Sites API (with support for other APIs coming soon).
Office 365 API Development in Visual Studio Office 365 API Tools for Visual Studio 2013 helps you to configure and integrate Office 365 APIs for your existing application and adds the required Office 365 API SDKs to your project.
I started building a mini reference deck that highlights key API entities and actions so you can quickly glance the slides to see if what you are looking for is supported or not.
Office 365 Discovery Service helps you to discover the available service capabilities for your app along with the respective service resource Ids and endpoint URIs.
If you are looking for cross-platform development within Visual Studio, Xamarin is a great option to build applications not just for Windows, also for iOS and Android devices in C#, the language we all love.
Along with the Office 365 API Tools for Visual Studio 2013, you also get a rich set of Office 365 API .NET and Cordova client libraries to interact with the Office 365 APIs.
Now that Office 365 APIs are generally available, you would want to go integrate Office data into your applications and are looking for resources for you to get started.
Today at TechEd Europe, Microsoft announced the general availability of Office 365 APIs which means the Office 365 API Tools and the Client Libraries have also RTMed!