Configuration providers (JSON, XML, INI, Environment, Azure, etc.)?

Short answer: ASP.NET Core supports multiple configuration providers: JSON (default) Environment Variables Command Line Args INI files XML files In-memory Azure App Configuration Azure Key Vault Secrets Manager Each can be chained with priority.

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.