systemdesign42/system-design-academy

System Design Academy is a curated learning resource for software engineers who want to understand how large-scale systems are built and how to discuss them in interviews. System design is the practice of planning how the different parts of a software system, databases, servers, caches, APIs, fit together to handle millions of users reliably. The repository is essentially a structured index of articles and case studies, organized alphabetically and by category. It covers three main areas: real-world case studies (how companies like Netflix, Instagram, Airbnb, Google, and Discord actually built their systems), system design fundamentals (core concepts like load balancing, caching, distributed databases, and message queues), and interview preparation (how to approach and structure answers in system design interviews). You would use this if you are a software engineer preparing for technical interviews at large tech companies, or if you simply want to understand the engineering decisions behind popular apps and services, why Google Search is built the way it is, how Dropbox scaled to millions of users, or how Discord handles real-time messaging. The content is delivered primarily through a linked newsletter rather than code in the repository itself.