How does GitHub search all repositories so quickly?

The article provides a detailed overview of system design, focusing on building a code search engine for GitHub. The author discusses challenges related to indexing and searching within repositories, emphasizing scalability and performance of the system. A key point is the application of various technologies, such as NoSQL databases and search engines, which allow for efficient management of large data sets. Furthermore, the article addresses microservices architecture that enables better organization and management of code. In the final part, the author suggests that complex systems require careful planning and thoughtful architecture to meet growing user expectations.