ASP.NET Core interview prep

Convention-based: a class with a RequestDelegate constructor and InvokeAsync . Created once and reused for every request, so it behaves like a singleton.
Factory-based: implements IMiddleware and is resolved from DI per request, so scoped constructor dependencies are fine.

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Fresher · 0–2 yrs Mid · 2–5 yrs Senior · 5+ yrs

Every answer has the same parts: what to say, the follow-up you'll likely get, and the trap that catches most candidates. Filter by your level, but skim one level above it; that's where offers are won.

Examples target .NET 8 and .NET 10, both long-term support releases. Each answer notes whether it comes from a source we opened (with a link) or is a widely reported pattern.