Sidio.Sitemap.AspNetCore is a lightweight .NET library for generating sitemaps and a sitemap index in ASP .NET Core applications.
Add the package to your project.
// di setup
services.AddDefaultSitemapServices<HttpContextBaseUrlProvider>();
// controller
[HttpGet]
public IActionResult Sitemap()
{
var nodes = new List<SitemapNode> { new ("page.html"), new (Url.Action("Index")) };
var sitemap = new Sitemap(nodes);
return new SitemapResult(sitemap);
}