System Design Problems

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Build a containerization system with namespace isolation, cgroups resource limiting, and image layering

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Build an HTTP web server supporting keep-alive connections, request pipelining, and multiple handler types

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Build a distributed version control system with content-addressable storage, branching, merging, and conflict resolution

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Build a DNS resolver with recursive resolution, zone file management, caching, and TTL-based invalidation

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Design cache layer supporting millions of QPS with high hit rate.

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Design GCS/S3-like storage for 100B+ objects with 99.99% durability.

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Build Kafka-like system supporting 1M+ messages/sec with exactly-once semantics.

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Generate unique IDs for 1B+ objects with ordering guarantees (Snowflake-like).

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Support autocomplete for search across 1B+ documents in <100ms.

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Generate feed for 2B+ users. Display photos/videos with minimal latency.

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Process 1000s of payments/sec. Ensure ACID transactions and fraud detection.

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Search across 1B+ messages with sub-second response time.

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Process 1000s of payments/sec with 99.999% uptime and fraud prevention.

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Support 5M+ concurrent voice/video calls with quality optimization.

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Support 10M+ concurrent users messaging with <100ms latency.

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Recommend products to 300M+ customers real-time and offline.

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Design recommendation engine for 200M+ users, 10K+ titles, real-time viewing data.

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Match millions of drivers with riders in real-time. Minimize matching time and distance.

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Track location of 1M+ drivers at sub-second latency for millions of subscribers.

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Design distributed key-value store with single-digit latency at scale.

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Design wide-column NoSQL database for massive scale with strong consistency.

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Build distributed index for 100B+ web pages supporting billions of queries/day.

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Detect and mitigate DDoS attacks for millions of websites globally.

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Suggest friends to 3B+ users based on various signals. Real-time and offline components.

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Rank feed items for 3B+ users. Maximize engagement and time spent.

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Search and rank 100M+ jobs for 900M users. Real-time relevance and personalization.

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Generate personalized feed for 900M users. Show top posts, articles, jobs in real-time.

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Design CDN for distributing video to 200M users globally with minimal latency.

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Route traffic to optimal origin across multiple regions and providers.

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Rate limit API requests across distributed servers. Support various strategies.

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Design the core matching algorithm for a ride-sharing service that optimizes driver-rider pairing.

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Design a real-time leaderboard system for a multiplayer online game with millions of concurrent players. The system should handle score updates, rankings, and friend comparisons.

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Design a real-time messaging platform like Slack or Discord supporting channels, direct messages, file sharing, and presence indicators.

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Design a high-frequency stock trading platform handling order matching, real-time price updates, and trade execution with microsecond latency.

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Design a calendar application supporting event scheduling, recurring events, shared calendars, and meeting room booking.

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Design a distributed task scheduler like Apache Airflow or Temporal that can handle millions of scheduled jobs with dependencies.

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Design the video processing pipeline that encodes uploaded content into multiple formats and resolutions for streaming.

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Design a real-time fraud detection system for financial transactions that can identify suspicious patterns with minimal false positives.

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Design a globally distributed DNS system like Cloudflare or Route 53 that handles billions of queries per day.

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Design a food delivery platform like DoorDash or Uber Eats handling restaurant listings, order management, and real-time delivery tracking.

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Design a distributed lock service like Apache ZooKeeper or etcd for coordinating distributed systems.

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Design a real-time collaborative editing system supporting multiple simultaneous editors with conflict resolution.

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Design a multi-channel notification system supporting push notifications, email, SMS, and in-app messages at scale.

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Design a distributed web crawler that can index billions of web pages efficiently while being polite to websites.

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Design a metrics collection and monitoring system like Datadog or Prometheus handling millions of time-series data points.

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Design a feature flag management system for controlled rollouts, A/B testing, and kill switches.

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Design an event sourcing architecture for a financial application requiring complete audit trails.

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Design an automated content moderation system for a social media platform using ML and human review.

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Design a graph database system optimized for social network queries and recommendation engines.

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Design an API gateway that handles authentication, rate limiting, routing, and request transformation for microservices.

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Design a microblogging platform where users post tweets, follow others, like, retweet, and view a timeline feed.

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Design a video sharing and streaming platform supporting upload, transcoding, streaming, recommendations, comments, and likes.

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Design a real-time messaging application like WhatsApp supporting 1-on-1 chat, group chat, media sharing, and message delivery receipts.

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Design a ride-sharing application matching drivers with passengers, handling real-time location tracking, fare calculation, and payments.

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Design a global video streaming platform that serves millions of concurrent users with personalized recommendations and adaptive bitrate streaming.

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Design a photo-sharing social media platform like Instagram. Users can upload photos, follow others, like posts, and view a personalized feed.

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Design a system like bit.ly that converts long URLs into short, memorable links. The system should handle billions of URLs with high availability and low latency.

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Design a strategy to migrate a monolithic system serving 10M users to microservices with zero downtime.

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Design an incident management process and supporting systems for a 24/7 operation with 99.99% uptime requirements.

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Design an organizational structure for scaling an engineering team from 20 to 200 engineers while maintaining velocity.

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As an Engineering Manager, design a system to identify, prioritize, and systematically address technical debt across your organization.

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Design an internal developer platform strategy to improve developer productivity and standardize infrastructure across 50+ engineering teams.

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As a Software Architect, design a framework for making and documenting architectural decisions across multiple teams.

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Design a reliability program using SLOs (Service Level Objectives) to balance feature velocity with system stability.

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Design a mapping and navigation service like Google Maps with features like map rendering, directions, and real-time traffic.

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Design a payment processing system like Stripe or PayPal handling transactions, refunds, and fraud detection.

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Design a real-time collaborative document editing system like Google Docs supporting multiple concurrent editors.

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Design a distributed caching system like Redis or Memcached that can handle millions of requests per second.

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Design a distributed rate limiting system to protect APIs from abuse and ensure fair usage.

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Design a ride-sharing application like Uber supporting real-time driver matching, location tracking, and fare calculation.

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Design a real-time messaging application like WhatsApp supporting 1:1 chat, group chat, media sharing, and delivery receipts.

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Design a photo-sharing social network like Instagram with features like posting photos, following users, and a personalized feed.

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Design a URL shortening service like bit.ly or TinyURL. The system should generate short URLs from long ones and redirect users.

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Design a microblogging platform like Twitter with features like posting tweets, following users, timeline, and trending topics.

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Design a video streaming platform like Netflix or YouTube supporting video upload, transcoding, and adaptive streaming.

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Explain different database sharding strategies and when to use each.

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When should you choose microservices over a monolithic architecture? What are the trade-offs?

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Explain the CAP theorem and its implications for distributed system design.

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Compare horizontal scaling (scaling out) vs vertical scaling (scaling up). What are the trade-offs?

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Explain the differences between an API Gateway and a Load Balancer. When would you use each?