I'm completely new to SPAs world and I'd like to build one using ASP.NET Core MVC as a back-end. But I don't know how to handle authentication in this case and the single user authentication option in visual studio is grayed out when choosing Web API.
Most of the web apps on the internet use separate pages for login and register(or one page for login/register, for example, asana.com) for security reasons and page loading speed. How should my project look like to achieve a similar effect to asana.com? I'm really confused. Should I have a separate Web API project for the API and separate project for the website using the API or a single project with identity system and just use [Authorize] on controllers returning JSON for my js framework? There aren't many tutorials or courses on the web regarding this topic nor project samples on Github.