Build your own X

build-your-own-x is a massive, community-curated roadmap of hands-on tutorials that teach you to re-implement complex systems from scratch—things like databases, compilers, operating systems, interpreters, web servers, neural networks, regex engines, and more. Rather than offering abstract theory, it organizes step-by-step guides by topic and by programming language, so you can pick a project that fits your stack and skill level. The focus is on demystifying internals: you don’t just use a tool, you build a working version of it, which naturally deepens your understanding of algorithms, protocols, and performance trade-offs. Categories include everything from graphics and cryptography to search engines and version control, making it a practical jumping-off point for portfolio pieces or study projects. Because most items are self-contained tutorials or repositories, you can progress incrementally and switch topics without losing momentum.