In-memory pub/sub with prioritiesOO designDesign and code a publish/subscribe system that runs on one machine: topics, subscribing, unsubscribing and publishing. Follow-up: messages carry a priority and higher-priority…
Last asked Apr 2026
#pub/sub
Design live comments for live videosSystem designDesign real-time comments on live video broadcasts: viewers post comments and everyone watching the same video sees them appear within a second or two, even when a popular stream…Last asked Apr 2026
Design a replay system for publish-subscribeSystem designPublishers send messages to subscribers through a pub-sub system. Design a replay feature that lets a subscriber receive past messages again from a chosen point. Cover how…Last asked Mar 2026
Design stock price alertsSystem designUsers set alerts such as "tell me when this stock goes above a price". Design the system that watches live prices and notifies the right users quickly. Cover how alert rules are…Last asked Dec 2025- Design a high-throughput publish-subscribe event systemSystem designProducers publish events on topics and many subscribers receive the events they subscribed to. Design it for very high throughput: subscription management, fan-out, delivery…Last asked Sep 2025