Design a Book Purchase Broker
Company: Sentry.Io
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Overview: Design a system for brokering book purchase requests across partner bookstores with target price constraints and expiration windows. The question evaluates API design, asynchronous fan-out, idempotent order placement, payment coordination, retry handling, and observability for unreliable external dependencies.