Build Amazon's Product Search Ranking Premium
Design a search ranking system that incorporates real-time inventory, pricing, and sales velocity signals into results, personalizes rankings per user, and re-indexes a product catalog of 500 million items.
Build Amazon's Review Aggregation Pipeline Premium
Design a review processing pipeline that deduplicates submissions, filters fraudulent reviews using behavioral signals, computes rolling star averages, and surfaces the most helpful reviews per product.
Build an API Key Management System Premium
Design an API key platform that issues scoped keys with per-key rate limits, propagates revocations to all gateway nodes within 1 second, and provides usage analytics per key without adding latency to the hot path.
Build a Bot Detection System Using Behavioral Signals Premium
Design a bot detection system that distinguishes human users from automated bots using behavioral and network signals, works without user-visible challenges, and updates its models as bots adapt their behavior.
Build a Columnar Storage Engine with SSTable and Compaction Premium
Design a write-optimized storage engine that buffers writes in memory, flushes them to immutable SSTables on disk, and runs background compaction to merge files while keeping read amplification low.
Build a Comment Threading System with Infinite Nesting Premium
Design a comment system that supports infinitely nested replies, renders full comment trees efficiently at any depth, and allows collapsing subtrees without loading the entire thread.
Build Facebook Live Low-Latency Video Streaming Premium
Design a live video streaming infrastructure that ingests a broadcaster's stream, encodes it into multiple bitrates in real-time, and delivers it to millions of concurrent viewers with under 5 seconds of latency.
Build Facebook News Feed Ranking and Fanout Premium
Design a news feed system that generates a personalized ranked feed for 3 billion users, handles write fanout for posts with millions of followers, and serves the feed in under 500ms.
Build Faceted Search with Live Inventory Filters Premium
Design a search system that supports multi-dimensional filter combinations (brand, price, rating, availability) and reflects live inventory changes in filter counts within seconds of a product going out of stock.
Build a Game Matchmaking System Premium
Design a matchmaking service that balances player skill (ELO rating), network latency, and queue wait time to form fair and low-lag matches, and degrades gracefully by relaxing skill constraints as queue times grow.