When software engineers search for , they are usually hunting for the definitive open-source notes, repositories, and architectural frameworks pioneered by Alex Xu (often phonetically misspelled as Wu). Alex Xu is the creator of ByteByteGo and author of the acclaimed [ System Design Interview – An Insider's Guide ] (https://bytes.usc.edu/~saty/courses/docs/data/SystemDesignInterview.pdf). His methodologies have become the industry standard for clearing high-level design (HLD) engineering loops at companies like Meta, Google, and Amazon.