Two‐factor authentication (2FA)?

Short answer: Supported out of the box in ASP.NET Core Identity. Options: SMS (via provider) Email Authenticator app (TOTP) Enable via Identity configuration: services.Configure<IdentityOptions>(options => { options.SignIn.RequireConfirmedEmail = true; }); Use SignInManager<T> to handle verification and token generation. Filters & Middleware Overlaps

Real-world example (ShopNest)

A ShopNest checkout request flows through middleware, hits a minimal API or controller, uses scoped services, and returns ProblemDetails on errors.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.