What is authentication vs authorization?

Short answer: Authentication: Verifying the identity of a user (Who are you?) Authorization: Determining if the authenticated user has permission to perform an action (What are you allowed to do?) In ASP.NET Core, both are handled via middleware and attributes like [Authorize], roles, and policies.

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.