What is the Circuit Breaker pattern, and how does it help to maintain system resilience?

Short answer: The Circuit Breaker pattern is used to detect and prevent failures from cascading through a system by stopping requests to a service that is known to be failing.

Explain a bit more

How it helps resilience: When a service starts failing, the circuit breaker trips and prevents further requests from being made to the failing service. This helps to protect the rest of the system and gives the failing service time to recover. It improves system stability by avoiding repetitive failures that would otherwise cause further damage or delays. Implementation:

Real-world example (ShopNest)

If Payment is down, the Order service fails fast with a circuit breaker instead of hanging every checkout thread.

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.