Windows Home Server Vail Preview: Add-ins and the Software Development Kit (SDK)

WARNING!  Windows Home Server Vail Preview is an early test build of the next version of Windows Home Server.  As such, it is not in any way, shape, or form ready for you to MOVE any important data from your current Windows Home Server (or other machine) to a Vail powered machine.  Doing so without proper backups elsewhere may put that data at great risk of being lost forever.

In addition, certain features you see may *not* be in the released version.  Certain features you do *not* see *may* be incorporated in the released version.

One of the big successes of the first Windows Home Server platform was the rapid growth in community developed add-ins for the platform. Whilst commercial software developers decided not to jump on the operating system (with a few notable exceptions), community development took off quickly, with over 120 add-ins created for Windows Home Server.

As with v1, Windows Home Server Vail is an extensible platform, and Microsoft have made a number of investments to take extensibility to the next level with a brand new SDK (available to download and try out during the beta period pre-launch), a new Online Catalog built into the dashboard for approved third-party applications, as well as extending the areas of the platform that can be developed and customised. Let’s take a look at what’s new.

Add-in Changes

Unfortunately, all of those v1 add-ins you love are going to have to be re-coded by the developers, as v1 add-ins will not be compatible in Windows Home Server Vail. Indeed, Vail brings a brand new file extension for add-ins (.wssx) which you’ll come to know very well I’m sure over the coming years.

Looking at the SDK, Microsoft have made a number of additional improvements to add-in development, including the ability for users to be automatically notified when add-in updates are available.

New Extensibility

Many more areas of Windows Home Server can be modified by developers in Vail. including:


  • Add high level Dashboard Tab/tabs
  • Your own high level tab can contain sub tabs
  • Tabs / Sub tabs can be of the following different types:
  • List View tabs/sub tabs: add-ins have the option not to use custom UI, but instead use the rendered common list view UI with many extensible parts. This allows users to enjoy a common look and feel regardless of who developed the add-in
  • Custom control tabs/sub tabs: Custom control tabs can be Winforms based OR WPF ( Windows Presentation Foundation) based
  • Default Tabs are extensible – the SDK will walk you through them
  • Add your own sub tabs under these tabs
  • Add more data to the existing tabs, such as task, columns, details
  • Home page is extensible: Add common tasks and community links


  • Add categories and tasks to the Launchpad

Remote Website:

  • You can add your own link in an online services section, create a new item in the menu bar, create a new gadget for the home page

The SDK & Provider Framework

A new framework called the “Provider Framework” is an architectural layer that performs all the business data processing and holds state for each feature. The SDK will help you build your own set of providers.


This time around, the SDK appears to be much more comprehensive then v1 providing:

  • How-to documents that helps you understand how to build add-ins
  • Templates that help you build the add-ins
  • Samples that provide examples of complete add-ins
  • API references that help you understand all the of the API elements that can be used to extend and manage “Vail”
  • An end-to-end sample that helps you understand how all of the extensible parts of the “Vail” servers can be connected

With a more comprehensive set of tools available, we’ll look forward to more and even better quality add-ins hitting the community in the months to come.

If you have any questions or wish to discuss the SDK, be sure to visit our dedicated Vail Beta forums.


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