Design a News Subscription Processing Engine
Company: Optiver
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: hard
Interview Round: Online Assessment
Overview: Design a news subscription engine that receives items, manages subscriptions, and publishes each item to matching subscribers. Clarify predicate and delivery semantics while addressing duplicate requests, concurrent removal, subscriber ordering, retries, partial fan-out recovery, backpressure, isolation, and operational visibility.