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Databases System Design Case Studies

InterviewSkool tracks 38 Databases case studies with architecture diagrams, scale estimates, and deep dives.

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Companies

Topics

Distributed Systems 90Real-time 51Storage 43Data Pipelines 42API Design 41Databases 38Caching 37Security 32AI / ML 23Algorithms 20Scheduling 20Search 19Event Driven 14Fintech 14Payments 11Geospatial 11Analytics 11Observability 11E-commerce 11Messaging 10CDN 9Concurrency 8Ads 8Frontend 8Booking System 6Networking 5IoT 4Media 3Media Streaming 3Collaboration 3Rate Limiting 2
DatabasesClear all
Access Control System (RBAC + Resource Permissions)
6 min readSecurityDatabasesAPI Design
Intermediate▶ Mock
Highly Reliable Account Balance System (Wallet / Ledger)
5 min readFintechPaymentsDatabases
Intermediate▶ Mock
Ads Platform Data Model (OLTP and Reporting)
5 min readAdsDatabasesAnalytics
Intermediate▶ Mock
Bidirectional Data Sync Dashboard
5 min readDistributed SystemsEvent DrivenDatabases
Intermediate▶ Mock
Concurrent Car Reservation Service
4 min readBooking SystemDatabasesConcurrency
Intermediate▶ Mock
University Course Registration System
4 min readBooking SystemDatabasesConcurrency
Intermediate▶ Mock
CRUD APIs with Asynchronous Background Jobs
4 min readAPI DesignSchedulingDatabases
Beginner▶ Mock
Daily Puzzle Platform (Wordle-style)
3 min readAPI DesignCachingDatabases
Beginner▶ 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 File System (GFS / HDFS)
5 min readStorageDistributed SystemsDatabases
Advanced▶ Mock
Distributed Key-Value Store (DynamoDB / Cassandra)
7 min readDatabasesDistributed SystemsStorage
Advanced+2▶ Mock
Demand-Side Ad Platform: Campaigns, Targeting and Edit History
3 min readAdsDatabasesAPI Design
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
Fixing a Flawed Database Table (Normalization and Indexes)
4 min readDatabases
Beginner▶ Mock
Globally Consistent (Linearizable) Metadata Service
4 min readDistributed SystemsDatabasesStorage
Advanced▶ Mock
Storing a Hierarchy and Returning All Descendants
4 min readDatabasesAPI DesignAlgorithms
Intermediate▶ Mock
Fast Host Listings Metrics Page (Airbnb)
4 min readAnalyticsDatabasesCaching
Intermediate▶ Mock
Train Search and Seat Availability DB Design (IRCTC)
4 min readDatabasesBooking SystemSearch
Intermediate▶ Mock
REST APIs for JSON Document Storage
3 min readAPI DesignStorageDatabases
Beginner▶ Mock
Word Store with Lexicographic Range Queries
4 min readStorageAlgorithmsDatabases
Intermediate▶ Mock
Scalable Likes System and Like Counter
5 min readDistributed SystemsCachingDatabases
Intermediate▶ Mock
Evaluating and Executing a MySQL to MongoDB Migration
4 min readDatabasesDistributed Systems
Intermediate▶ Mock
Optimizing Slow Queries on a Million-Row Table
3 min readDatabasesCaching
Beginner▶ Mock
Perishable-Goods Inventory and Location Tracking
3 min readE-commerceDatabasesEvent Driven
Intermediate▶ Mock
Portfolio Management System (HLD + DB Design)
3 min readFintechDatabasesAnalytics
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
Prompt Sharing Platform
5 min readAI / MLSecurityDatabases
Intermediate▶ Mock
Relational Database Internals (Write Path and Recovery)
7 min readDatabasesStorageDistributed Systems
Advanced▶ Mock
Cloud Resource Change Tracking Database
3 min readDatabasesEvent DrivenStorage
Intermediate▶ Mock
Secure Internal Web App for Sensitive Financial Data
4 min readSecurityAPI DesignDatabases
Intermediate▶ Mock
Highly Available Spring Boot Service with Background Jobs
4 min readDistributed SystemsSchedulingDatabases
Intermediate▶ Mock
Tagging System with Clean REST APIs (Confluence / Jira Labels)
3 min readAPI DesignDatabasesSearch
Beginner▶ Mock
Troubleshooting a Slow or Failing Production System
5 min readObservabilityDistributed SystemsDatabases
Intermediate▶ Mock
Voting System APIs and Data Model
3 min readAPI DesignDatabasesSecurity
Beginner▶ Mock

Frequently Asked Questions

What is Databases in system design?

Databases is a core system design topic covered in 38 case studies on InterviewSkool. It appears frequently in FAANG interviews, especially at Google, Amazon, and Meta.

How should I prepare Databases for system design interviews?

Study the case studies above, focusing on architecture trade-offs, scale estimates, and API designs. Practice explaining your decisions aloud — this is exactly what interviewers evaluate.

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