| IAuthServiceKeysProvider | Provides the keys of the OpenID Connect service to encrypt and sign JWT tokens issued by it. |
| IBinarySerializer | Defines the contract for a binary serializer that supports serialization and deserialization of objects to and from binary format. |
| IGrantTypeInformer | Provides information about OAuth 2.0 grant types supported by a component. Components implementing this interface can be registered in dependency injection to contribute their supported grant types to the OpenID Connect discovery endpoint. |
| IJsonObjectBinder | Provides a mechanism to bind data from a JsonObject to a model, enabling the conversion of JSON data into a strongly typed object. This interface abstracts the process of mapping JSON properties to a model's properties, facilitating the dynamic population of model instances with data from a JSON source. |
| IParametersProvider | Extracts a flat set of name/value pairs from a response object — the reverse of binding — for delivery as query, fragment or form_post parameters. The transport adapters (MVC, Minimal API) share this contract because flattening a response DTO is framework-neutral; the implementation lives in the core for the same reason. |
| IParameterValidator | Provides a method for validating that a parameter is and not null. |
| IRequestInfoProvider | Provides information about the current request, including URIs and security details. |
| IUserCredentialsAuthenticator | Validates a username and password pair against the host's user store and produces an authorized grant when the credentials are correct. Used by the Resource Owner Password Credentials grant (grant_type=password) at the token endpoint, so the host can plug its own identity backend behind the OAuth flow. |