# WinRT API in C# scripts for UWP

> Use WinRT API directly in Unity scripts for UWP.

Unity includes Windows Runtime (WinRT) support when building for Universal Windows Platform with the [IL2CPP](/engine/6000.5/manual/scripting/compilation-and-code-reload/script-compilation/backends/il2cpp.md) scripting backend. Use Windows Runtime support to call into both native system Windows Runtime APIs as well as custom .winmd files directly from managed (C#) scripts and plugins.

Unity automatically references Windows Runtime APIs such as `Windows.winmd` on Universal Windows Platform. To use custom .winmd files, import them into your Unity project folder together with any accompanying DLLs and configure them. For more information, refer to [Import and configure plug-ins](/engine/6000.5/manual/scripting/compilation-and-code-reload/plug-ins/plug-in-inspector.md).

To use WinRT API in your Unity scripts:

* Your scripts must be written in C#.
* All the code that uses WinRT API must be under the `ENABLE_WINMD_SUPPORT` [directive](/engine/6000.5/manual/scripting/compilation-and-code-reload/script-compilation/conditional-compilation/platform-dependent-compilation.md). This is necessary because the Editor uses [Mono](/engine/6000.5/manual/scripting/compilation-and-code-reload/script-compilation/backends/mono.md), which doesn't support WinRT APIs.

The following code example gets an advertising ID using WinRT API directly:

```lang-cs
using UnityEngine;
public class WinRTAPI : MonoBehaviour
{
    void Update()
    {
        auto adId = GetAdvertisingId();
        // ...
    }

    string GetAdvertisingId()
    {
        #if ENABLE_WINMD_SUPPORT
            return Windows.System.UserProfile.AdvertisingManager.AdvertisingId;
        #else
            return "";
        #endif
    }
}
```

## Additional resources

* [Windows build settings reference](/engine/6000.5/manual/platform-specific/windows/standalone-binaries.md)
* [Scripting backends](/engine/6000.5/manual/scripting/compilation-and-code-reload/script-compilation/backends.md)