# system-design-primer | Donne Martin | Knowledge Base | Instagit Learn how to design large-scale systems. Prep for the system design interview. Includes Anki flashcards. GitHub Stars: 336k Repository: https://github.com/donnemartin/system-design-primer --- ## Articles ### [Reverse Proxy vs Load Balancer: Key Differences and Use Cases](/donnemartin/system-design-primer/reverse-proxy-vs-load-balancer-differences) Learn the key differences between reverse proxies and load balancers. Discover how reverse proxies secure and optimize access, while load balancers ensure scalability and fault tolerance for your applications. - Tags: deep-dive - Published: 2026-02-24 ### [How to Scale a System to Millions of Users on AWS: A Step-by-Step Architectural Guide](/donnemartin/system-design-primer/how-to-scale-system-millions-users-aws) Learn how to scale a system to millions of users on AWS with this step-by-step architectural guide. Discover strategies for incremental growth and robust performance. - Tags: architecture - Published: 2026-02-24 ### [LRU Cache Implementation Using Object-Oriented Design Principles: Python Guide](/donnemartin/system-design-primer/lru-cache-implementation-object-oriented-design) Learn LRU cache implementation with object-oriented Python. Achieve O(1) retrieval and insertion using a hash map and doubly-linked list, with automatic eviction. - Tags: deep-dive - Published: 2026-02-24 ### [How to Design Amazon's Sales Ranking by Category Feature: A Complete System Design Guide](/donnemartin/system-design-primer/how-to-design-amazons-sales-ranking-by-category) Design Amazon's sales ranking by category feature using MapReduce and a REST API. Learn to handle 100 billion monthly reads efficiently with a complete system design guide. - Tags: how-to-guide - Published: 2026-02-24 ### [Performing Back-of-the-Envelope Calculations for System Design: A Complete Guide](/donnemartin/system-design-primer/back-of-the-envelope-calculations-system-design) Master back-of-the-envelope calculations for system design. Learn to estimate requirements, performance, and cost quickly without coding. Essential guide for engineers. - Tags: how-to-guide - Published: 2026-02-24 ### [CDN Integration and Effective Caching Strategies for Global Content Delivery](/donnemartin/system-design-primer/cdn-integration-and-caching-strategies) Master CDN integration and effective caching strategies for global content delivery. Learn how CDNs speed up latency and reduce server load for seamless worldwide access. - Tags: tutorial - Published: 2026-02-24 ### [How to Design a Key-Value Store for High Performance: Architecture and Implementation Guide](/donnemartin/system-design-primer/how-to-design-key-value-store-high-performance) Learn to design a high-performance key-value store using in-memory caching, consistent hashing, and durable persistence. Explore essential architecture and implementation details for massive scalability and fault tolerance. - Tags: how-to-guide - Published: 2026-02-24 ### [Horizontal vs Vertical Scaling: Pros, Cons, and Architectural Trade-offs](/donnemartin/system-design-primer/horizontal-vs-vertical-scaling-pros-and-cons) Understand horizontal vs vertical scaling pros cons architectural trade-offs. Learn which scaling method is best for your system design. - Tags: deep-dive - Published: 2026-02-24 ### [Consistency Patterns in Distributed Systems: Strong, Eventual, and Weak Consistency Explained](/donnemartin/system-design-primer/consistency-patterns-strong-eventual-weak) Understand strong, eventual, and weak consistency patterns in distributed systems. Learn how each guarantees data accuracy and when to apply them for optimal performance. - Tags: deep-dive - Published: 2026-02-24 ### [How to Design a Social Network Data Structure for Efficient Querying: A Complete System Design Guide](/donnemartin/system-design-primer/how-to-design-social-network-data-structure) Design an efficient social network data structure using sharded graph storage and BFS traversal for sub-second user connection path querying across distributed servers. - Tags: tutorial - Published: 2026-02-24 ### [Microservices Architecture Patterns and Service Discovery Methods: A Complete Technical Guide](/donnemartin/system-design-primer/microservices-architecture-patterns-and-service-discovery) Explore microservices architecture patterns and service discovery methods. Learn how to build scalable, resilient systems with technologies like Consul etcd and Zookeeper. - Tags: tutorial - Published: 2026-02-24 ### [How to Design a Scalable Web Crawler: Architecture & Implementation Guide](/donnemartin/system-design-primer/how-to-design-scalable-web-crawler) Learn to design a scalable web crawler with our architecture and implementation guide. Discover how to handle billions of pages using a distributed queue-based system. - Tags: how-to-guide - Published: 2026-02-24 ### [Caching Strategies: Cache-Aside, Write-Through, and Write-Behind Explained](/donnemartin/system-design-primer/caching-strategies-cache-aside-write-through-write-behind) Understand caching strategies like cache-aside write-through and write-behind. Learn how these patterns balance read performance write latency and data consistency to optimize your system. - Tags: tutorial - Published: 2026-02-24 ### [Load Balancing Algorithms and Strategies: Active-Passive vs Active-Active Explained](/donnemartin/system-design-primer/load-balancing-algorithms-and-strategies) Learn active-passive vs active-active load balancing strategies. Understand how each method distributes traffic and handles failover to optimize server performance and uptime. - Tags: deep-dive - Published: 2026-02-24 ### [Implementing Database Replication: Master-Slave vs Master-Master Architectures](/donnemartin/system-design-primer/implementing-database-replication-master-slave-master-master) Master-slave vs master-master replication explained. Learn how to implement database replication for scalability and availability, choosing the right architecture for your needs. - Tags: deep-dive - Published: 2026-02-24 ### [Database Sharding Strategies and Their Implementation: A Technical Guide](/donnemartin/system-design-primer/database-sharding-strategies-and-implementation) Explore database sharding strategies like range, hash, directory, and geographic partitioning. Learn how to implement horizontal data partitioning for linear scalability and reduced I/O. - Tags: how-to-guide - Published: 2026-02-24 ### [SQL vs NoSQL Databases: When to Use Which for Your Application](/donnemartin/system-design-primer/sql-vs-nosql-databases-when-to-use) Learn when to use SQL vs NoSQL databases. Optimize your application by choosing between ACID transactions, complex joins, or horizontal scalability and flexible schemas. Master database selection. - Tags: deep-dive - Published: 2026-02-24 ### [Understanding the CAP Theorem and Its Implications on Distributed Systems](/donnemartin/system-design-primer/understanding-cap-theorem-and-implications) Grasp the CAP theorem's core concepts and its critical implications for distributed systems. Learn why Partition Tolerance is key in real-world architectures. - Tags: deep-dive - Published: 2026-02-24 ### [How to Design Twitter's Timeline and Search Functionality: A Complete System Architecture](/donnemartin/system-design-primer/how-to-design-twitters-timeline-and-search) Design Twitter's timeline and search functionality with a robust distributed system. Learn to handle 500 million daily tweets using caching, databases, and search clusters. - Tags: how-to-guide - Published: 2026-02-24 ### [How to Design a URL Shortening Service Like Bit.ly: A Complete System Design Guide](/donnemartin/system-design-primer/how-to-design-url-shortening-service) Design a URL shortening service like Bit.ly. Learn about MD5 hashing, Base62 encoding, database choices, caching, and API design for a complete system. - Tags: guide - Published: 2026-02-24 ### [How to Approach a System Design Interview Question: The 4-Step Framework](/donnemartin/system-design-primer/how-to-approach-system-design-interview-question) Master system design interview questions with our 4 step framework. Outline requirements, create high-level design, drill into components, and identify bottlenecks for success. - Tags: how-to-guide - Published: 2026-02-24