Welcome to my System Designs repository! 🚀 This repository contains detailed system design documents covering various real-world applications and architectures.
This repository serves as a comprehensive learning resource for understanding how to design and architect large-scale distributed systems. Each document provides:
- Problem statement - Real-world scenarios
- System requirements - Functional & non-functional
- High-level architecture - Component breakdown
- Scalability considerations - Horizontal & vertical scaling
- Database design - Schema design with SQL/NoSQL choices
- API design - RESTful endpoints and data flow
- Caching, load balancing, and optimizations - Performance tuning
- Trade-offs and alternative approaches - Why choose X over Y
- Code examples - Pseudocode and implementation snippets
- Capacity estimations - Real-world calculations
Follow this structured learning path to build your system design knowledge progressively:
Estimated Time: 2-3 hours per topic
| Status | Topic | Key Concepts | Difficulty |
|---|---|---|---|
| ✅ | URL Shortener | Hashing, Base62 encoding, Redis caching, Database sharding | ⭐⭐ |
What you'll learn:
- Basic distributed system patterns
- Caching strategies with Redis
- Database sharding and partitioning
- Hash-based URL generation
- Handling high read traffic
Estimated Time: 4-6 hours per topic
| Status | Topic | Key Concepts | Difficulty |
|---|---|---|---|
| ✅ | Video Streaming Platform | CDN, Video transcoding, HLS/DASH, Multi-tier caching | ⭐⭐⭐ |
| ✅ | Rate Limiter | Token bucket, Sliding window, Redis, Distributed systems | ⭐⭐⭐ |
What you'll learn:
- Multi-service architecture
- Content delivery networks (CDN)
- Adaptive bitrate streaming
- Video processing pipelines
- DRM and security
- SQL vs NoSQL trade-offs
Estimated Time: 6-8 hours per topic
| Status | Topic | Key Concepts | Difficulty |
|---|---|---|---|
| ✅ | Ride-Sharing System (Uber) | Geospatial indexing, WebSockets, Real-time matching | ⭐⭐⭐⭐ |
| ✅ | Real-time Chat Application (WhatsApp/Slack) | WebSockets, Message queues, Presence detection | ⭐⭐⭐⭐ |
| 📝 | E-commerce System | Inventory management, Payment processing, Order fulfillment | ⭐⭐⭐⭐ |
| 📝 | Distributed Search Engine | Inverted index, Ranking algorithms, Elasticsearch | ⭐⭐⭐⭐⭐ |
What you'll learn (Ride-Sharing):
- Redis GEO for geospatial driver matching
- WebSocket scaling for real-time location tracking
- Surge pricing algorithms
- Distributed locks to prevent double-booking
- Geographic database sharding
- Fraud detection patterns
What you'll learn (Chat Application):
- WebSocket bidirectional communication
- Multi-tier storage (PostgreSQL + Cassandra)
- Message delivery guarantees (sent, delivered, read)
- Online presence and typing indicators
- Redis Pub/Sub for horizontal scaling
- Group chat fan-out patterns
- End-to-end encryption (Signal Protocol)
Legend:
- ✅ Complete with detailed documentation
- 🚧 In progress
- 📝 Planned
Learn fundamental patterns that appear across multiple system designs:
| Concept | Where It's Used | Read More |
|---|---|---|
| Caching Strategies | URL Shortener, Video Streaming | concepts/caching-strategies.md |
| Database Sharding | URL Shortener, Chat Systems | concepts/database-sharding.md |
| Database Replication | High Availability, Read Scaling | concepts/database-sharding.md#database-replication |
| Load Balancing | All Systems | concepts/load-balancing.md |
| API Design Patterns | All Systems | concepts/api-design-patterns.md |
| Message Queues | Video Streaming, Async Processing | concepts/message-queues.md |
| Consistency Patterns | Distributed Systems | concepts/consistency-patterns.md |
| WebSockets & Real-Time | Chat, Live Updates | concepts/websockets-realtime.md |
| Search & Indexing | E-commerce, Content Platforms | concepts/search-indexing.md |
| Distributed Transactions | E-commerce, Financial Systems | concepts/distributed-transactions.md |
| Geospatial Systems | Ride-Sharing, Location Services | concepts/geospatial-systems.md |
| Notification Systems | All User-Facing Applications | concepts/notification-systems.md |
| Service Discovery | Microservices, Distributed Systems | concepts/service-discovery.md |
| Circuit Breaker & Resilience | All Distributed Systems | concepts/circuit-breaker-resilience.md |
| CDN Architecture | Video Streaming, Static Content | Video Streaming - CDN |
- Start with Beginner Level to understand core patterns
- Practice explaining each system's architecture out loud
- Focus on trade-offs and alternative approaches
- Review the "Miscellaneous" sections for deep technical details
- Read documents in the suggested order
- Try to design the system yourself before reading the solution
- Compare your design with the documented approach
- Understand the "why" behind each decision
- Use the Core Concepts section to understand specific patterns
- Check architecture diagrams for visual understanding
- Review code examples for implementation guidance
Design a scalable URL shortening service that handles millions of requests per day.
Key Features:
- Generate short URLs from long URLs
- Fast redirection (sub-10ms)
- Custom short URLs
- Click analytics and tracking
- URL expiration
Technologies: Redis, PostgreSQL, Base62 encoding, Consistent hashing
Architect a distributed video streaming platform with adaptive bitrate streaming.
Key Features:
- Video upload and storage
- Video transcoding pipeline
- Adaptive bitrate streaming (HLS, MPEG-DASH, CMAF)
- CDN-based content delivery
- DRM and content protection
Technologies: AWS S3, FFmpeg, CDN (CloudFront/Akamai), MongoDB, PostgreSQL, Widevine/FairPlay DRM
Deep Dive Topics:
- SQL vs NoSQL Database Choices
- Video Transcoding Pipeline
- Streaming Workflow (HLS/DASH/CMAF)
- Digital Rights Management (DRM)
- CDN Caching Strategies
Design a distributed rate limiting system to prevent API abuse and ensure fair usage.
Key Features:
- Multiple rate limiting algorithms (Token Bucket, Leaky Bucket, Sliding Window)
- Distributed rate limiting with Redis
- Multi-tier limits (free, premium, enterprise)
- Per-IP, per-user, per-endpoint limiting
- Graceful degradation strategies
Technologies: Redis, Lua scripts, Token Bucket algorithm, Sliding Window Counter
Key Concepts:
- 5 rate limiting algorithms compared
- Distributed systems with Redis Cluster
- Atomic operations with Lua scripts
- Multi-tier and composite rate limiting
Design a real-time ride-sharing platform with driver-rider matching and live location tracking.
Key Features:
- Real-time driver-rider matching within 2-3 seconds
- Live location tracking with WebSockets
- Surge pricing based on supply/demand
- Multi-region deployment
- Fraud detection and GPS validation
Technologies: Redis GEO, WebSocket, PostgreSQL (sharded), Cassandra, Kafka, Geohashing
Key Concepts:
- Geospatial indexing with Redis GEO commands
- Real-time communication at scale (1M concurrent connections)
- Distributed locks to prevent double-booking
- Saga pattern for cross-region trips
- ETA and fare calculation algorithms
- Grid-based surge pricing
Design a scalable real-time messaging platform with one-on-one chat, group messaging, and online presence.
Key Features:
- One-on-one and group messaging
- Message delivery status (sent, delivered, read)
- Online presence and typing indicators
- Message history with pagination
- Media sharing (images, videos, documents)
- Push notifications for offline users
- Full-text message search
Technologies: WebSocket, Redis Pub/Sub, PostgreSQL, Cassandra, Kafka, Elasticsearch, S3
Key Concepts:
- WebSocket scaling with Redis Pub/Sub
- Multi-tier storage strategy (hot/warm/cold)
- Message delivery guarantees
- Conversation-based database sharding
- Rate limiting for spam prevention
- End-to-end encryption (Signal Protocol)
- Fan-out patterns for group chat
- E-commerce Platform (Amazon)
- Social Media Feed (Twitter/Instagram)
- Distributed Cache (Redis Cluster)
- Message Queue System (Kafka/RabbitMQ)
- Logging and Monitoring System
To get the most out of this repository, you should have basic knowledge of:
- Databases: SQL (PostgreSQL/MySQL) and NoSQL (MongoDB/Redis)
- Networking: HTTP/HTTPS, DNS, Load Balancing
- Programming: Basic understanding of Python, SQL, or any programming language
- Data Structures: Arrays, Hash Maps, Trees
- System Concepts: Caching, Queues, REST APIs
Don't worry if you're not an expert in all of these - the documents explain concepts as they're used!
Found a typo? Have a suggestion? Want to add a new system design?
Feel free to open an issue or submit a pull request. All contributions are welcome!
If you found this repository helpful, please consider giving it a star ⭐
Happy Learning! 🚀