microsoft-extensions-configuration

You can validate configuration at startup by binding appsettings.json to strongly typed Options classes and enabling ValidateOnStart with dependency injection. This fail-fast behavior stops the application immediately if required fields are missing or invalid.

IValidateOptions enables complex cross-property, conditional, and dependency-aware validation for production-grade settings. By registering this interface with dependency injection, you enforce logical rules across multiple bound properties that Data Annotations cannot handle.

The options pattern maps appsettings.json sections into POCO settings classes for safer, maintainable access. Using dependency injection, it provides strongly typed configuration data throughout your application, preventing late runtime failures caused by misconfigured settings.

Yes, you can apply Data Annotations directly to strongly typed Options classes to enforce correctness. Combined with ValidateOnStart, this stops the app early if configuration violates attribute rules like required fields or value ranges.

You need IOptionsMonitor for environment-aware configuration and background-worker settings requiring monitored lifetimes. It supports scenarios where configuration values must be retrieved dynamically and react to changes, unlike static IOptions instances.

You add post-configuration steps during options binding to modify or enrich settings after initial mapping. This allows you to compute derived values or apply conditional logic before the configuration is finalized and validated at startup.