Guided tracks

System design practice

Tackle curated drills with a friendly walkthrough, then jump straight into the sandbox to validate your architecture.

URL Shortener
Easy
Design a scalable URL shortening service like bit.ly or TinyURL
Hashing algorithmsDatabase designCachingScalability

Learn base62 encoding, distributed ID generation, and cache-aside patterns

Topic:Storage & Caching
Time:15-20 min
Start Practice
Pastebin
Easy
Design a text paste sharing service for creating, storing, and sharing text snippets
Object storageCDN cachingUnique ID generationTTL expiration

Learn blob storage patterns, CDN for static content, and metadata vs content separation

Topic:Storage & CDN
Time:15-20 min
Start Practice
Twitter Feed
Medium
Design a social media timeline that handles millions of users
Fan-out architectureFeed generationCachingReal-time updates

Push vs pull models, Redis for timeline caching, and handling celebrity users

Topic:Fan-out & Real-time
Time:25-30 min
Coming soon...
Instagram Photo Sharing
Medium
Build a photo sharing platform with upload, storage, and feed
CDNObject storageImage processingFeed ranking

S3 for storage, CloudFront CDN, image optimization, and ML ranking

Topic:CDN & Storage
Time:25-30 min
Coming soon...
Netflix Video Streaming
Hard
Design a video streaming service that serves millions globally
Adaptive bitrateCDN strategyContent deliveryDRM

HLS/DASH protocols, edge caching, regional replication, bandwidth optimization

Topic:Content Delivery
Time:35-45 min
Coming soon...
Uber Ride Matching
Hard
Real-time ride matching system with geo-location
Geo-hashingWebSocketsReal-time matchingSurge pricing

QuadTrees for location, WebSocket connections, pub-sub for real-time updates

Topic:Geo-location
Time:35-45 min
Coming soon...
WhatsApp Messaging
Hard
End-to-end encrypted messaging system at scale
Message queuesEncryptionPresence systemGroup chats

Kafka for message delivery, Signal protocol, last-seen tracking

Topic:Messaging & Encryption
Time:35-45 min
Coming soon...
Amazon Product Catalog
Medium
E-commerce catalog with search, filtering, and inventory
Search indexingInventory managementCachingSharding

Elasticsearch for search, Redis for inventory, database sharding strategies

Topic:Search & Inventory
Time:25-30 min
Coming soon...
YouTube Video Upload
Hard
Handle video uploads, transcoding, and storage
Upload optimizationVideo transcodingCDNStorage

Chunked uploads, FFmpeg transcoding pipeline, S3 + CloudFront architecture

Topic:Video Processing
Time:35-45 min
Coming soon...
Slack Messaging Platform
Medium
Team communication with channels, threads, and search
WebSocketsMessage persistenceSearchNotifications

Real-time messaging, Elasticsearch for search, push notifications

Topic:Real-time & Search
Time:25-30 min
Coming soon...
Dropbox File Sync
Hard
File synchronization across devices with conflict resolution
ChunkingDelta syncConflict resolutionVersioning

Block-level deduplication, Merkle trees, CRDT for conflict resolution

Topic:File Sync & Versioning
Time:35-45 min
Coming soon...