This library simplifies creating configuration for your C# app/service by utilizing the serialization capabilities of Json.NET to serialize nested (custom) objects, dictionaries and lists as simply as by creating a POCO and inheriting JsonSettings class.
INI format: This will require to rewrite the library and add an abstraction layer that will allow saving into an INI format or any other format. Right now the library is "hardcoded" into using Newtonsoft.Json and I do not have the time right now to do it but eventually I'll.
Regarding the interface implementation,
To what exactly do you refer? You can just create two settings classes that implement shared interface.
hi please add interface support for settings and ini format. like this library https://github.com/aloneguid/config#declare-settings-interface