A step-by-step walkthrough of building a standalone authentication service using ASP.NET Core Identity and Razor Pages. Covers four approaches to setting up Identity (pre-configured template, scaffolding, manual setup, and rolling your own), then walks through manual implementation including DbContext setup with IdentityDbContext, Startup configuration, and building registration, login, logout, and account management pages. Key Identity classes like UserManager and SignInManager are explained in context, along with Razor Pages-specific patterns like BindProperty, page handlers, TempData, and folder-level authorization conventions.
