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System Design Practice Questions

Each question below runs the way a real system design round unfolds: clarify requirements, define the API and data model, sketch the architecture on a live canvas, and defend your trade-offs. Prompts are free to read, and every step of a submitted answer is graded with specific feedback.

11 questions
  1. 01Design IoT Monitoring PlatformDesign a real-time IoT monitoring platform that ingests temperature, humidity, and pressure readings from millions of sensors worldwide. Support real-time dashboards with 5-minute rolling averages, t…Hard
  2. 02Design WhatsApp / Chat SystemDesign a real-time messaging platform like WhatsApp or Facebook Messenger. Handle 1:1 and group messaging, online presence, read receipts, media sharing, end-to-end encryption, and guaranteed message…Hard
  3. 03Design URL ShortenerDesign a URL shortening service like Bitly or TinyURL. Handle billions of short links, high read throughput, custom aliases, analytics tracking, and link expiration at scale.Medium
  4. 04Design Notification SystemDesign a notification platform that delivers push notifications, emails, SMS, and in-app messages across multiple channels. Handle user preferences, templating, priority levels, throttling, and deliv…Medium
  5. 05Design YouTube / Video StreamingDesign a video sharing and streaming platform like YouTube. Handle video uploads, transcoding, adaptive bitrate streaming, recommendations, and content delivery at the scale of 500 hours of video upl…Hard
  6. 06Design Uber / Ride SharingDesign a ride-sharing platform like Uber or Lyft. Handle real-time driver location tracking, rider-driver matching, ETA computation, surge pricing, trip management, and payments at the scale of milli…Hard
  7. 07Design Web CrawlerDesign a web crawler that systematically downloads and indexes billions of web pages. Handle URL discovery, politeness policies, duplicate detection, distributed coordination, and content extraction…Hard
  8. 08Design Rate LimiterDesign a distributed rate limiting service that protects APIs from abuse and overload. Support multiple algorithms (token bucket, sliding window), per-user and per-API limits, distributed counting ac…Medium
  9. 09Design Payment SystemDesign a payment processing platform like Stripe or Razorpay. Handle payment initiation, authorization, capture, refunds, webhook notifications, and reconciliation at the scale of millions of transac…Hard
  10. 10Design Dropbox / File SyncDesign a cloud file storage and synchronization service like Dropbox or Google Drive. Handle file uploads, chunked storage, real-time sync across devices, conflict resolution, sharing and permissions…Hard
  11. 11Design Twitter (Full Scale)Design a global social media platform like Twitter. This covers high-volume ingestion, hybrid fan-out, real-time analytics, search indexing, and system reliability at the scale of 500 million tweets…Hard
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