microsoft-extensions-configuration

You can validate .NET configuration at startup by binding settings to POCOs and applying Data Annotations or custom IValidateOptions<T> logic. This checks for invalid settings during startup, ensuring the application fails immediately rather than encountering runtime errors.

IOptions provides singleton configuration values, IOptionsSnapshot recomputes values per request scope, and IOptionsMonitor provides real-time configuration updates. Choosing the right option lifetime ensures settings behave correctly across web, background, and test scenarios.

Complex cross-property validation for strongly-typed options is implemented using the IValidateOptions<T> interface. This allows you to define dependency-driven validation rules that execute at startup, catching intricate misconfigurations that simple Data Annotations cannot handle.

Yes, you can normalize configuration values before they are used by applying post-configuration hooks. This allows you to adjust or compute derived settings immediately after binding, ensuring the strongly-typed options are fully prepared for the application.

Yes, startup validation works with background services and test scenarios. By binding to strongly-typed settings and applying validation, you can ensure consistent configuration checks across web, background, and test environments to prevent runtime failures.