Clarify QPS, consistency, payment flow, failure modes. Sketch API, DB, queues, idempotency, observability. ShopNest order service publishes OrderPaid for email/inventory.
Capco rounds often probe: Banking/fintech consulting.
Themes commonly reported in public MNC interview experiences (AmbitionBox / LinkedIn / Glassdoor-style). Practice aloud; keep answers this short in the real round.