I recently needed to add a Razor view to an existing ASP.NET Core API project. This is a relatively straightforward task, and this article documents the necessary steps.

1. Install the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package.

2. Update Startup.cs:

   • Change services.AddControllers() to services.AddControllersWithViews(). (See the Remarks section of the documentation for more details about what this does.)
   • Add these method calls:

     services
        .AddRazorPages()
        .AddRazorRuntimeCompilation();
     

3. Add a Controller with a route. For example, if your Razor view is to display invoices, the controller could be something like this:

    [Route("[controller]")]
    public class InvoicesController : Controller
    {
        [AllowAnonymous]
        public async Task<IActionResult> Index(CancellationToken cancellationToken)
        {
            var invoices = await GetInvoicesAsync(cancellationToken);
   
            return View(invoices);
        }
    }
   

4. Add a view in a folder which matches the controller's class and method names. In this case, that would be: Views/Invoices/Index.cshtml.

That's it! You can now go to whatever the root URL for your API is, add /Invoices and the view will load.