Environment-based configuration (Development, Staging,?

Short answer: Production) ASP.NET Core uses the ASPNETCORE_ENVIRONMENT variable to determine the runtime environment. Supported environments (by convention): Development Staging Production Environment-specific logic can be applied: if (env.IsDevelopment()) { ... } Also used to load: appsettings.{env}.json Startup{env}.cs (in older versions)

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.