Dependency Inversion: Decoupling Your Domain

Dependency Inversion (DIP) is the final piece of the SOLID puzzle. It flips the traditional dependency tree on its head.

Avoiding the Low-Level Trap

Usually, high-level business logic depends on low-level details like database drivers or API clients. DIP suggests that the business logic should define an interface (e.g., UserRepository) that the low-level module then implements.

Why It's Powerful

This makes your core business logic completely independent of the infrastructure. You can swap out your database, your external services, or your UI layer without touching the heart of your application.