Event Store: Optionally, you can store events in an event store to keep track of all?

Short answer: events for event sourcing. This allows services to replay events and rebuild their state if needed.

Real-world example (ShopNest)

After payment succeeds, ShopNest publishes OrderPaid. Inventory and Notification services react independently—no giant distributed transaction.

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.