Once, I was needed to have a simple endpoint in which I can send any request for test purposes. Just a simple web service that eats a request, no matter what HTTP method and route are used.
Fortunately, Microsoft did a great job making ASP.NET Core as flexible as possible, so the solution turned up quite short and simple.
Imagine a quite common client-server application where the server exposes REST methods and the client communicates using HTTP requests. Requests and responses are serialized in JSON format. There might be a problem if you try to send and receive a DTO that contains a collection of interfaces or abstract classes. I will talk about the usage of Web API and Newtonsoft Json.NET as its underlying serialization library.