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System Design Case Studies Tracker

Real system design questions from FAANG and top tech companies, each with architecture diagrams, scale estimates, API designs and trade-offs. Browse by company or topic.

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176case studies
30companies
31topics
~5 minaverage read

Companies

Topics

Coupon Distribution System
7 min readDistributed SystemsSecurityEvent Driven
Advanced—▶ Mock
Gaming Leaderboard (Top K)
16 min readDistributed SystemsReal-timeStorage
Beginner▶ Mock
Google Drive
16 min readStorageCDNDistributed Systems
Advanced▶ Mock
Instagram
17 min readDistributed SystemsMediaSearch
Advanced+2▶ Mock
Live Streaming (Instagram Live/YouTube Live)
14 min readMedia StreamingCDNReal-time
Beginner—▶ Mock
Netflix – Streaming Service
17 min readMedia StreamingCDNStorage
Advanced▶ Mock
Push Notification Service
17 min readReal-timeMessagingDistributed Systems
Advanced+5▶ Mock
MakeMyTrip – Hotel Booking System
20 min readDistributed SystemsPaymentsBooking System
Beginner+3▶ Mock
Messenger App
9 min readReal-timeMessagingDistributed Systems
Advanced+5▶ Mock
Search Engine (Google)
15 min readSearchDistributed SystemsStorage
Advanced—▶ Mock
Shazam
14 min readSearchReal-timeAlgorithms
Advanced—▶ Mock
Booking.com Design
5 min readBooking SystemSearchGeospatial
Beginner—▶ Mock
Web Crawler
15 min readDistributed SystemsStorageSearch
Advanced+2▶ Mock
Live Location Sharing App
4 min readGeospatialReal-timeDistributed Systems
Beginner—▶ Mock
Snap Map Design
5 min readGeospatialReal-timeDistributed Systems
Beginner—▶ Mock
BookMyShow
9 min readDistributed SystemsPaymentsBooking System
Beginner▶ Mock
Uber Design (Ride-Hailing)
5 min readGeospatialReal-timeDistributed Systems
Advanced+2▶ Mock
A/B Testing (Experimentation) Platform
5 min readAnalyticsData PipelinesDistributed Systems
Intermediate▶ Mock
Access Control System (RBAC + Resource Permissions)
6 min readSecurityDatabasesAPI Design
Intermediate▶ Mock
Highly Reliable Account Balance System (Wallet / Ledger)
5 min readFintechPaymentsDatabases
Intermediate▶ Mock
Ad Click and Impression Aggregator
6 min readAdsAnalyticsData Pipelines
Advanced+2▶ Mock
Ad Creative Relationship Processing with an External Model API
5 min readAdsData PipelinesAI / ML
Intermediate▶ Mock
Ad Frequency Capping Service (Netflix Ads)
7 min readAdsReal-timeCaching
Advanced▶ Mock
Ad Budget Pacing System
5 min readAdsReal-timeDistributed Systems
Advanced▶ Mock
Ads Audience Targeting System
5 min readAdsData PipelinesCaching
Advanced▶ Mock
Ads Platform Data Model (OLTP and Reporting)
5 min readAdsDatabasesAnalytics
Intermediate▶ Mock
Tracing and Debugging AI Agent Tool Calls
5 min readAI / MLObservabilityDistributed Systems
Intermediate▶ Mock
Analytics Dashboard for an AI Chat Product
5 min readAnalyticsAI / MLData Pipelines
Intermediate▶ Mock
Android MVVM Architecture for API-Driven Screens
4 min readFrontendAPI DesignCaching
Intermediate▶ Mock
Reviewing an Existing Architecture for Risks
6 min readDistributed SystemsSecurityObservability
Intermediate▶ Mock
ML Pipeline to Predict Document Aspect Ratio (Adobe)
5 min readAI / MLData Pipelines
Intermediate▶ Mock
Multi-Tenant Audit Logs Service
4 min readSecurityStorageData Pipelines
Intermediate▶ Mock
Autonomous Vehicle Camera Perception Pipeline
5 min readAI / MLReal-timeConcurrency
Advanced▶ Mock
Bidirectional Data Sync Dashboard
5 min readDistributed SystemsEvent DrivenDatabases
Intermediate▶ Mock
Calendar Service (Google Calendar)
6 min readSchedulingDistributed SystemsStorage
Intermediate+2▶ Mock
Concurrent Car Reservation Service
4 min readBooking SystemDatabasesConcurrency
Intermediate▶ Mock
ChatGPT-Style Conversational AI Service
7 min readAI / MLReal-timeDistributed Systems
Advanced+2▶ Mock
CI/CD Platform (GitHub Actions / Jenkins)
7 min readSchedulingDistributed SystemsStorage
Advanced▶ Mock
User Behavior Tracking (Clickstream Analytics)
6 min readAnalyticsData PipelinesReal-time
Intermediate▶ Mock
Cloud Console Home Page (Backend-for-Frontend)
4 min readFrontendAPI DesignCaching
Intermediate▶ Mock
Cloud Development Environment (Codespaces / Replit / DevBox)
7 min readDistributed SystemsSecurityScheduling
Advanced▶ Mock
Coffee Ordering System with Real-Time Notifications
6 min readE-commerceReal-timeAPI Design
Beginner▶ Mock
Real-Time Collaborative Editor (Google Docs / Sheets)
7 min readCollaborationReal-timeDistributed Systems
Advanced▶ Mock
Color Suggestion System (Adobe)
4 min readAI / MLAPI DesignCaching
Intermediate▶ Mock
Content Moderation System (Harmful Post Detection)
6 min readAI / MLSecurityData Pipelines
Advanced▶ Mock
Core Dump Collection and Crash Analysis System
5 min readObservabilityStorageData Pipelines
Intermediate▶ Mock
University Course Registration System
4 min readBooking SystemDatabasesConcurrency
Intermediate▶ Mock
Credit Card Authorization, Limits and Reporting
4 min readFintechPaymentsReal-time
Advanced▶ Mock
Credit Card Customer Portal
5 min readFintechSecurityAPI Design
Beginner▶ Mock
Cross-Region Event Processing Platform
4 min readEvent DrivenDistributed SystemsMessaging
Advanced▶ Mock
CRUD APIs with Asynchronous Background Jobs
4 min readAPI DesignSchedulingDatabases
Beginner▶ Mock
Daily Puzzle Platform (Wordle-style)
3 min readAPI DesignCachingDatabases
Beginner▶ Mock
Real-Time Data Stream Processor
4 min readData PipelinesReal-timeDistributed Systems
Intermediate▶ Mock
Digital Game Store and Distribution Platform (Steam)
6 min readE-commercePaymentsCDN
Intermediate▶ Mock
Inventory Serving on Spinning Disks with Little RAM
5 min readStorageDatabasesAlgorithms
Advanced▶ Mock
Distributed Cache and the Hot Key / Cache Stampede Problem
6 min readCachingDistributed SystemsDatabases
Intermediate▶ Mock
Distributed Crossword Solver
6 min readAlgorithmsDistributed SystemsScheduling
Advanced▶ Mock
Distributed File System (GFS / HDFS)
5 min readStorageDistributed SystemsDatabases
Advanced▶ Mock
Distributed Job Scheduler (Cron at Scale)
7 min readSchedulingDistributed SystemsEvent Driven
Advanced+7▶ Mock
Distributed Key-Value Store (DynamoDB / Cassandra)
7 min readDatabasesDistributed SystemsStorage
Advanced+2▶ Mock
Centralized Logging System (ELK / Splunk)
6 min readObservabilityData PipelinesSearch
Intermediate+1▶ Mock
Finding the Mode of Data Spread Across Many Machines
4 min readAlgorithmsDistributed SystemsData Pipelines
Intermediate▶ Mock
Distributed Rate Limiter
8 min readRate LimitingDistributed SystemsAPI Design
Intermediate+9▶ Mock
Reusable Dropdown / Select Component (Frontend System Design)
4 min readFrontendAPI Design
Intermediate▶ Mock
Demand-Side Ad Platform: Campaigns, Targeting and Edit History
3 min readAdsDatabasesAPI Design
Intermediate▶ Mock
Duplicate File Detection at Scale
6 min readStorageAlgorithmsDistributed Systems
Intermediate▶ Mock
E-commerce Tables and Indexes for Recent-Spend Queries
3 min readDatabasesE-commerce
Beginner▶ Mock
E-commerce Shopping Website (and Fixing Cart Latency)
5 min readE-commerceCachingDatabases
Intermediate▶ Mock
911 Emergency Call Routing Platform
5 min readReal-timeDistributed SystemsGeospatial
Advanced▶ Mock
Enterprise AI Agent for a Global Company
5 min readAI / MLSecurityDistributed Systems
Advanced▶ Mock
Entitlement-Aware Agentic Workflow for Portfolio Requests
4 min readAI / MLFintechSecurity
Advanced▶ Mock
Expense Policy and Violation Processing (Rippling)
5 min readFintechDistributed SystemsEvent Driven
Advanced▶ Mock
Sorting a 500 GB CSV with 16 GB of RAM (External Merge Sort)
4 min readAlgorithmsStorageData Pipelines
Intermediate▶ Mock
Faceted Product Search at Large Scale (Amazon)
4 min readSearchE-commerceDistributed Systems
Intermediate▶ Mock
First-Time Kubernetes Deployment in a New Cloud
4 min readDistributed SystemsSecurityNetworking
Intermediate▶ Mock
Fitness Tracking App (Strava-style)
3 min readGeospatialStorageAPI Design
Intermediate▶ Mock
Fixing a Flawed Database Table (Normalization and Indexes)
4 min readDatabases
Beginner▶ Mock
Flight Search Platform (Google Flights / Kayak)
4 min readSearchCachingData Pipelines
Advanced▶ Mock
Food and Quick-Commerce Delivery Platform (Uber Eats / DoorDash)
6 min readGeospatialReal-timeE-commerce
Advanced▶ Mock
Globally Consistent (Linearizable) Metadata Service
4 min readDistributed SystemsDatabasesStorage
Advanced▶ Mock
Governed Data Service for Downstream Consumers
3 min readAPI DesignData PipelinesSecurity
Intermediate▶ Mock
GPU Cluster Control Plane (Host Health, Repair and Job Dispatch)
7 min readObservabilitySchedulingDistributed Systems
Advanced▶ Mock
Simple Greeting-Card Web App (MVP Architecture)
4 min readAPI DesignStorageCDN
Beginner▶ Mock
High-Volume Healthcare Data Ingestion Pipeline
4 min readData PipelinesSecurityStorage
Advanced▶ Mock
Storing a Hierarchy and Returning All Descendants
4 min readDatabasesAPI DesignAlgorithms
Intermediate▶ Mock
Low-Latency Holiday Lookup Service
4 min readCachingAPI DesignFintech
Beginner▶ Mock
Streaming Homepage Rows with Viewport Loading and Deduplication (Netflix)
4 min readFrontendAPI DesignCaching
Intermediate▶ Mock
Fast Host Listings Metrics Page (Airbnb)
4 min readAnalyticsDatabasesCaching
Intermediate▶ Mock
Hosting Many Websites on One Server with One IP Address
4 min readNetworkingSecurityDistributed Systems
Beginner▶ Mock
Preventing Duplicate Request Processing (Idempotency Keys)
4 min readAPI DesignDistributed SystemsPayments
Beginner▶ Mock
Scalable Image Processing Service
5 min readData PipelinesSchedulingStorage
Intermediate▶ Mock
Incident Ticket Correlation Platform
3 min readObservabilityData PipelinesDistributed Systems
Advanced▶ Mock
Interactive SQL Query Notebook (Snowflake)
4 min readAPI DesignSchedulingStorage
Intermediate▶ Mock
IoT / Sensor Telemetry Pipeline
7 min readIoTData PipelinesStorage
Intermediate+1▶ Mock
Train Search and Seat Availability DB Design (IRCTC)
4 min readDatabasesBooking SystemSearch
Intermediate▶ Mock
Automated Jira-Ticket-to-Pull-Request System
4 min readAI / MLSchedulingDistributed Systems
Advanced▶ Mock
REST APIs for JSON Document Storage
3 min readAPI DesignStorageDatabases
Beginner▶ Mock
Large File Upload and Processing Pipeline
7 min readStorageData PipelinesSecurity
Intermediate▶ Mock
Word Store with Lexicographic Range Queries
4 min readStorageAlgorithmsDatabases
Intermediate▶ Mock
Scalable Likes System and Like Counter
5 min readDistributed SystemsCachingDatabases
Intermediate▶ Mock
Live Comments for Live Video (Facebook Live / TikTok Live)
6 min readReal-timeMessagingDistributed Systems
Intermediate▶ Mock
Guardrails and Fallbacks for Reliable LLM Systems
4 min readAI / MLSecurityDistributed Systems
Intermediate▶ Mock
LLM Inference API with Dynamic Batching
7 min readAI / MLConcurrencyScheduling
Advanced▶ Mock
Highly Available Software Load Balancer
7 min readDistributed SystemsNetworkingAPI Design
Intermediate▶ Mock
Malicious IP and URL Detection Service
5 min readSecurityReal-timeCaching
Advanced▶ Mock
Interactive Map with 100 Million+ Points
4 min readGeospatialFrontendData Pipelines
Advanced▶ Mock
Real-Time Market Data Distribution and VWAP (Bloomberg)
5 min readFintechReal-timeDistributed Systems
Advanced▶ Mock
Matching Tagged Problems to Skilled Programmers at Scale
4 min readAlgorithmsDistributed SystemsScheduling
Advanced▶ Mock
Streaming Mention Analytics with Search and Alerts (Bloomberg)
3 min readReal-timeSearchAnalytics
Advanced▶ Mock
Metrics Monitoring and Alerting System
7 min readObservabilityData PipelinesStorage
Advanced+3▶ Mock
Mobile Banking App Backend
3 min readFintechSecurityPayments
Intermediate▶ Mock
Distributing Large Model Weights to Thousands of GPU Hosts
6 min readAI / MLDistributed SystemsStorage
Advanced▶ Mock
Multi-Carrier Parcel Shipping System
4 min readE-commerceAPI DesignEvent Driven
Intermediate▶ Mock
Personal Finance Dashboard from Multiple Providers
3 min readFintechAPI DesignCaching
Intermediate▶ Mock
Multi-Tenant Data Ingestion and Processing Platform
4 min readData PipelinesDistributed SystemsSecurity
Advanced▶ Mock
Multi-Vendor Integration Platform (Connectors for Email, Slack, CRMs)
4 min readAPI DesignSecurityEvent Driven
Intermediate▶ Mock
Multimodal RAG Assistant over an Internal Knowledge Base
4 min readAI / MLSearchData Pipelines
Advanced▶ Mock
Evaluating and Executing a MySQL to MongoDB Migration
4 min readDatabasesDistributed Systems
Intermediate▶ Mock
Large-Scale Near-Duplicate Video Detection
4 min readAI / MLMediaSearch
Advanced▶ Mock
News Aggregator (Google News)
6 min readSearchData PipelinesCaching
Intermediate▶ Mock
Object Storage Service (Amazon S3) with Deduplication
6 min readStorageDistributed SystemsAPI Design
Advanced▶ Mock
Offline Multi-Device E-Book Reader (Kindle-style)
3 min readStorageAPI DesignCollaboration
Intermediate▶ Mock
Real-Time Online Auction (eBay / Live Auctions)
7 min readReal-timeDistributed SystemsPayments
Advanced▶ Mock
Online Bookstore with Price Aggregation
7 min readE-commerceAPI DesignCaching
Intermediate▶ Mock
Online Chess Platform (chess.com)
6 min readReal-timeDistributed SystemsMessaging
Intermediate▶ Mock
Online Judge and Coding Contest Platform (LeetCode)
6 min readDistributed SystemsSecurityScheduling
Intermediate▶ Mock
Making Many HTTP Requests Fast (Within Rate Limits)
3 min readConcurrencyAPI DesignRate Limiting
Intermediate▶ Mock
Optimizing Slow Queries on a Million-Row Table
3 min readDatabasesCaching
Beginner▶ Mock
Pastebin (Share Text by Link)
4 min readStorageCachingAPI Design
Beginner▶ Mock
Payment Processing System (Stripe-style)
6 min readPaymentsFintechDistributed Systems
Advanced+1▶ Mock
PDF Viewer Search Box that Cycles Through Matches (React)
4 min readFrontendAlgorithmsConcurrency
Intermediate▶ Mock
Perishable-Goods Inventory and Location Tracking
3 min readE-commerceDatabasesEvent Driven
Intermediate▶ Mock
"Played by Your Friends" Social Summary (Roblox)
3 min readDistributed SystemsCachingReal-time
Intermediate▶ Mock
Portfolio Management System (HLD + DB Design)
3 min readFintechDatabasesAnalytics
Intermediate▶ Mock
Post Privacy and Visibility System (Facebook-style)
4 min readSecurityDistributed SystemsCaching
Advanced▶ Mock
Social Post Search (Keyword and Boolean Queries)
6 min readSearchDistributed SystemsAlgorithms
Intermediate▶ Mock
Smart Grid Control over Unreliable Devices
7 min readIoTDistributed SystemsReal-time
Advanced▶ Mock
Price Drop Tracker (CamelCamelCamel)
5 min readE-commerceSchedulingData Pipelines
Intermediate▶ Mock
High Availability and Failover for a Primary-Replica Database
4 min readDatabasesDistributed Systems
Intermediate▶ Mock
E-commerce Product Catalog and Price Updates
6 min readE-commerceCachingDatabases
Intermediate▶ Mock
Explaining Your Own Project Architecture (and Scaling It Up)
5 min readDistributed SystemsDatabasesCaching
Beginner▶ Mock
AI Prompt Playground (OpenAI / Anthropic Console)
6 min readAI / MLFrontendStorage
Intermediate▶ Mock
Prompt Sharing Platform
5 min readAI / MLSecurityDatabases
Intermediate▶ Mock
Proximity Search (Yelp / Nearby Restaurants)
7 min readGeospatialSearchCaching
Intermediate▶ Mock
Publisher Configuration Rules and Safe Global Rollout
5 min readAdsDistributed SystemsCaching
Intermediate▶ Mock
Pub/Sub System with Replay (Seek Back in Time)
3 min readMessagingDistributed SystemsStorage
Advanced▶ Mock
Recommendation System (Candidate Generation + Ranking)
6 min readAI / MLData PipelinesDistributed Systems
Advanced▶ Mock
Relational Database Internals (Write Path and Recovery)
7 min readDatabasesStorageDistributed Systems
Advanced▶ Mock
Enterprise Remote Browser Isolation System
3 min readSecurityDistributed SystemsScheduling
Advanced▶ Mock
Cloud Resource Change Tracking Database
3 min readDatabasesEvent DrivenStorage
Intermediate▶ Mock
Global Restaurant Chain Menu Update System
4 min readDistributed SystemsCDNCaching
Intermediate▶ Mock
Scaling a Rules Engine for High Traffic (Rippling)
3 min readDistributed SystemsAlgorithmsEvent Driven
Advanced▶ Mock
Runtime Localization System (i18n)
4 min readFrontendAPI DesignCDN
Intermediate▶ Mock
Secure Multi-Tenant API for an Enterprise AI Copilot
4 min readAI / MLSecurityAPI Design
Advanced▶ Mock
Secure Internal Web App for Sensitive Financial Data
4 min readSecurityAPI DesignDatabases
Intermediate▶ Mock
Security Monitoring Framework for Cloud Infrastructure
4 min readSecurityObservabilityData Pipelines
Advanced▶ Mock
Aggregator Service over Many Downstream Microservices
3 min readDistributed SystemsAPI DesignCaching
Intermediate▶ Mock
Data Engineering for a Short-Video App (TikTok-scale)
4 min readData PipelinesAnalyticsStorage
Advanced▶ Mock
Smartwatch Sensor Subsystem Design
4 min readIoTReal-timeData Pipelines
Intermediate▶ Mock
Highly Available Spring Boot Service with Background Jobs
4 min readDistributed SystemsSchedulingDatabases
Intermediate▶ Mock
Detecting and Reducing Stale Job Listings (LinkedIn)
4 min readData PipelinesAI / MLSearch
Intermediate▶ Mock
Stock Price Alert System
3 min readFintechReal-timeAlgorithms
Intermediate▶ Mock
Stock Trading Platform (Zerodha / Robinhood)
6 min readFintechPaymentsReal-time
Advanced▶ Mock
Street View Image Ingestion and Storage
4 min readMediaStorageData Pipelines
Advanced▶ Mock
Surge (Dynamic) Pricing for Ride-Hailing
4 min readReal-timeGeospatialAlgorithms
Advanced▶ Mock
Tagging System with Clean REST APIs (Confluence / Jira Labels)
3 min readAPI DesignDatabasesSearch
Beginner▶ Mock
Text-to-Video Generation Service (Sora)
6 min readAI / MLSchedulingDistributed Systems
Advanced▶ Mock
To-Do List Service (REST API and Real-Time Shared Lists)
5 min readAPI DesignReal-timeCollaboration
Beginner▶ Mock
Top-K Trending Items (Heavy Hitters)
7 min readAnalyticsReal-timeAlgorithms
Advanced+4▶ Mock
Troubleshooting a Slow or Failing Production System
5 min readObservabilityDistributed SystemsDatabases
Intermediate▶ Mock
Typeahead / Search Autocomplete
6 min readSearchCachingData Pipelines
Intermediate▶ Mock
URL Shortener (TinyURL / bit.ly)
7 min readDistributed SystemsCachingStorage
Beginner+4▶ Mock
User Activity Collection and Recent-Window Queries
5 min readAnalyticsData PipelinesStorage
Intermediate▶ Mock
Virtual Credit Card Service (Capital One)
6 min readFintechPaymentsSecurity
Intermediate▶ Mock
Voting System APIs and Data Model
3 min readAPI DesignDatabasesSecurity
Beginner▶ Mock
Human Avoidance for Autonomous Warehouse Robots
4 min readReal-timeAI / MLIoT
Advanced▶ Mock

Frequently Asked Questions

What are system design case studies?

System design case studies are real-world architecture problems broken down into structured breakdowns. Each case study covers requirements, high-level design, scale estimates, API designs, and deep dives into key components.

How many system design case studies should I prepare?

For FAANG interviews, preparing 15-20 case studies covering core topics like caching, load balancing, and database sharding is recommended. Focus on understanding trade-offs rather than memorizing solutions.

Which companies ask system design case studies?

All FAANG companies (Google, Amazon, Meta, Apple, Microsoft) plus top tech companies like Netflix, Uber, and Airbnb ask system design case studies. Senior-level interviews almost always include at least one system design round.

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