Build a Game Replay Storage and Scrubbing System Premium
Design a replay system that records every game event, lets players scrub to any point in a replay with under 1 second seek time, and serves millions of replay requests per day without straining the game servers.
Build a Geospatial Proximity Service Premium
Design a service that answers 'find all X within Y km of this location' in under 10ms at 500 million active entities, supports moving entities that update their location every few seconds.
Build Gmail's Spam Detection Pipeline Premium
Design a spam classification system that processes 300 billion emails per day, classifies each one in under 100ms before delivery, and continuously retrains models as spammers adapt their tactics.
Build Google Maps ETA Prediction Under Live Traffic Free
Design a route ETA system that incorporates real-time traffic signals from millions of moving devices, recalculates ETAs en route as conditions change, and serves predictions with under 200ms latency.
Build Google Photos Duplicate Detection Pipeline Premium
Design a pipeline that detects near-duplicate photos across 28 billion uploads per day using perceptual similarity rather than byte-level matching, and does so without storing a full copy of every image.
Build Google Search Autocomplete Premium
Design a typeahead suggestion engine that returns the top 10 relevant completions for any search prefix in under 50ms, personalizes results per user, and updates suggestions based on trending queries in near real-time.
Build a Hot-Cold Tiered Storage System Premium
Design an automated data tiering system that keeps frequently accessed data on fast NVMe SSDs, migrates aging data to object storage, and retrieves cold data transparently on access without application changes.
Build Instagram Explore Real-Time Recommendation Engine Premium
Design a content discovery system that generates a personalized Explore grid for 2 billion users, refreshes recommendations as users scroll, and surfaces trending content within minutes of it going viral.
Build an Inverted Index for Full-Text Search at 10B Documents Premium
Design a full-text search engine that builds and maintains an inverted index over 10 billion documents, returns results with relevance ranking in under 100ms, and updates the index in near real-time as documents are added.
Build a Last-Mile Delivery Tracking System Premium
Design a delivery tracking system that ingests GPS pings from thousands of drivers every few seconds, recalculates ETAs dynamically as conditions change, and streams live location updates to customers without polling.