Startup.cs

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        // Configure Web API for self-host. 
        var config = new HttpConfiguration();
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        // Adding to the pipeline with our own middleware
        app.Use(async (context, next) =>
        {
            // Add Header
            context.Response.Headers["X-Powered-By"] = "Owin Self Host";

            // Call next middleware
            await next.Invoke();
        });
        
        // Custom Middleare
        app.Use(typeof(CustomMiddleware));
        
        // Web Api
        app.UseWebApi(config);

        // Fik
        var options = new FileServerOptions
        {
            EnableDirectoryBrowsing = true,
            EnableDefaultFiles = true,
            DefaultFilesOptions = { DefaultFileNames = {"index.html"}},
            FileSystem = new PhysicalFileSystem("Assets"),
            StaticFileOptions = { ContentTypeProvider = new CustomContentTypeProvider() }
        };

        app.UseFileServer(options);
    }
}