43 live System Design scenarios
System Design Interview Questions
Easy Scenarios
1 challengesMedium Scenarios
10 challengesDesign 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-box typeahead for a large web search engine: popular completions for every prefix, shared by all users in a locale.
Design a Courier Payout Service
Design 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 a Hotel Reservation System
Design a system like Airbnb or Booking.com where users can search for and book rooms for specific date ranges.
Design Idempotent Request Replay
Design 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
32 challengesDesign an Ad Click Aggregator
Design a system to track ad clicks and aggregation for real-time analytics and billing.
Design a Multi-Tenant LLM Inference Platform
Design a global inference service for mixed chat, coding, and long-context workloads across heterogeneous accelerators, starting from one region and model.
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 a Dynamo-Style Highly Available Key-Value Store
Design a highly available, scalable, leaderless key-value store.
Design Dropbox
Design a cloud file synchronization service.
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 Product Search Autocomplete
Design personalized, trend-aware autocomplete and search suggestions for a large online store's product search, built around a ranking model you are given.
Design Slack
Design a real-time messaging platform for enterprises.
Design TikTok's For You Recommendations
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 GFS- or HDFS-style file system that stores petabytes of large files across thousands of servers in one data center for batch processing.
Design a Distributed Message Queue
Design a high-throughput distributed message queue similar to Apache Kafka, with durable replay from stored offsets.
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 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 high-volume system to ingest, store, and visualize metrics from large server fleets, similar to Datadog or Prometheus.
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 service that charges customers through external payment processors. Focus on correctness and idempotency.
Design Proximity Service
Design a location-based service like Yelp, Uber, or Google Maps Nearby.
Design a Ride-Sharing Service
Design a ride-matching service like Uber or Lyft with real-time location tracking.
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 a 100,000-seat event in minutes to millions of fans 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 a User-Uploaded Video Streaming Platform
Design upload, transcoding, storage, and playback for a global user-uploaded video platform.
Design a Web Crawler
Design a scalable web crawler like Googlebot to index the internet.