What is Dependency Inversion Principle?

Short answer: The Dependency Inversion Principle (DIP) states that: High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions. In other words: High-level business logic shouldn't depend on concrete implementations. Instead, both high- and low-level components should depend on interfaces or abstract classes.

Real-world example (ShopNest)

Patterns in ShopNest should solve a real pain (swappable payments, test seams)—not be added for decoration.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.