What is the Adapter pattern and how does it relate to SOLID?

Short answer: Adapter converts the interface of a class into another interface clients expect, allowing incompatible interfaces to work together. It promotes Open/Closed Principle (OCP) by enabling new integrations without modifying existing code.

Real-world example (ShopNest)

ShopNest payment fees use Strategy: IFeeCalculator with UPI/Card implementations chosen at runtime.

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.