53 live System Design scenarios
System Design Interview Questions
Easy Scenarios
1 challengesMedium Scenarios
14 challengesDesign an Ad Click Aggregator
Design a system to track ad clicks and aggregation for real-time analytics and billing.
Design a Cross-Product Tagging System
Design a shared tagging service that lets users apply tags to entities across multiple Atlassian products, with consistent search and deduplication.
Design a Work-Item Time Metrics Microservice
Design a microservice within a project-management platform that computes time-in-state and SLA metrics from work-item state history.
Design Typeahead
Design the search autocomplete system for Google Search.
Build a Courier Payout Service
Design and implement the service that calculates courier payouts from order activity and upstream timing data.
Design Date-Range File Storage
Design a file storage and indexing system that returns exactly the files created within a requested time interval.
Design Search Autocomplete
Design a scalable typeahead system for a search engine like Google or Amazon.
Design Slack
Design a real-time messaging platform for enterprises.
Design a No-Signup Media Hosting Service
Design a small image, GIF, and video hosting platform that lets users upload and share media without creating an account.
Design a Hotel Reservation System
Design a system like Airbnb or Booking.com where users can search for and book rooms for specific date ranges.
Build Idempotent Request Replay
Build a processor that consolidates duplicate JSON requests and guarantees each logical request is handled once.
Design a Leaderboard
Design a real-time gaming leaderboard (e.g., ESPN, Steam, MMOs).
Design a Notification System
Design a scalable notification service that sends emails, SMS, and push notifications to millions of users.
Design a Rate Limiter
Design a service to limit the number of requests a user can send to an API within a time window.
Hard Scenarios
38 challengesDesign Context and Memory for a Long-Running Agent
Design context curation, compression, retrieval, and durable memory for agents operating across many hours and context windows.
Design an Evaluation Platform for AI Agents
Design datasets, trace grading, simulation, regression detection, and release gates for non-deterministic tool-using agents.
Design a Multi-Tenant LLM Inference Platform
Design a global inference service for mixed chat, coding, and long-context workloads across heterogeneous accelerators.
Design Anonymous Group Messaging
Design a group messaging application where each member has a different masked identity in every group.
Architecture Deep Dive on Your Past Project
Defend the architecture of a real project you built, its constraints, trade-offs, failures, and how you would redesign it today.
Design a Chat Application
Design a real-time chat application like WhatsApp or Facebook Messenger.
Design Google Docs
Design a real-time collaborative document editor supporting multiple simultaneous users.
Design Amazon DynamoDB
Design a highly available, scalable, leaderless key-value store.
Design Discord Voice
Design a low-latency voice chat system for gamers.
Design Dropbox
Design a cloud file synchronization service.
Design Bigtable
Design a distributed wide-column NoSQL store.
Design Google Maps
Design a mapping service with route planning and ETA calculation.
Design Instagram Feed
Design a photo-sharing social network news feed with complex ranking.
Design TikTok Algo
Design a high-velocity video recommendation feed (For You Page).
Design Uber Surge Pricing
Design a dynamic pricing engine for a ride-sharing service.
Design a Distributed File System
Design a file storage and synchronization service like Google Drive, Dropbox, or HDFS.
Design a Fault-Tolerant Distributed LLM Training Platform
Design the training stack for a 100B+ parameter model across tens of thousands of accelerators.
Design a Distributed Message Queue
Design a high-throughput distributed message queue similar to Apache Kafka or RabbitMQ.
Design a Shared GPU Cluster Scheduler
Design scheduling and capacity management for training, research, and production inference on a large heterogeneous accelerator fleet.
Design Job Scheduler
Design a distributed job scheduler capable of handling recurring and one-time tasks at scale.
Design a Key-Value Store
Design a distributed key-value store like Dynamo or Cassandra with high availability.
Design an LLM Inference Performance Optimization Program
Design the measurement, kernel, rollout, and correctness system that closes the gap between theoretical and achieved inference throughput.
Design Reliable Software Updates for a Mars Rover
Design a system that transfers a large software update over an intermittent, low-bandwidth link and safely activates it on a remote rover.
Design a Merchandise Ranking Backend
Design a browsing backend that ranks merchandise using views, cart additions, wishlists, and purchase events.
Design a Political Advertising Safeguard System
Design a system to detect and prevent political advertisements from unauthorized foreign actors from appearing on a social media platform.
Design a Metrics Monitoring System
Design a system to ingest, store, and visualize metrics from millions of servers, similar to Datadog or Prometheus.
Design a Multi-Agent Research System
Design an orchestrator-worker agent system for open-ended research with parallel search, synthesis, citations, and bounded cost.
Design Multi-Tenant Vehicle Tracking
Design a shared real-time vehicle tracking platform used by ride-hailing, food delivery, and fleet-management products.
Design a Payment System
Design a reliable payment processing backend like Stripe or PayPal. Focus on correctness and idempotency.
Design Proximity Service
Design a location-based service like Yelp, Uber, or Google Maps Nearby.
Design Ride Sharing (Ober)
Design a ride-matching service like Uber or Lyft with real-time location tracking.
Design a Secure Cloud Coding Agent
Design isolated execution, permissions, credentials, networking, and auditability for an autonomous coding agent.
Design a Stock Exchange
Design an exchange that accepts orders, matches buyers and sellers, publishes market data, and preserves an auditable sequence of trades.
Design a Ticket Booking System
Design a high-concurrency ticket booking system (e.g., Ticketmaster) that can sell out millions of tickets in minutes without overselling.
Design Twitter Feed
Design a scalable news feed system where users can post tweets and follow other users.
Design Product Discovery Inside Video
Design a system that identifies products in video frames and surfaces relevant purchase links while viewers watch.
Design YouTube/Netflix
Design a global video streaming platform supporting millions of concurrent users.
Design a Web Crawler
Design a scalable web crawler like Googlebot to index the internet.