You Don’t Need an Interface for Everything

Most of us have been guilty of creating interfaces like IOrderService, IEmailService, and IPaymentService even when there’s only ever one concrete implementation. This video argues that many of those interfaces don’t actually add value unless you truly need to swap implementations, enable complex testing scenarios, or support multiple versions of a service.

It also traces this habit back to how Dependency Injection is taught in .NET, showing when interfaces really make sense (e.g., for pluggable components or mocking) and when a simple delegate or class override might do the job more cleanly.

Watch on YouTube