I Analyzed 17 Popular GitHub Repos — Here's What Their Codebases Are Actually Made Of

Draft for Dev.to — by Kim (getjustgo.com) Status: DRAFT — needs Kim review before publishing Tags: #github #opensource #python #devtools Cover image idea: A bar chart or treemap showing language breakdowns — colorful, data-forward. I wanted to answer a simple question: what are popular open source projects actually made of? Not what their README says. Not what their marketing page claims. What does the code itself reveal? So I pointed RepoCrunch — a deterministic repo analyzer I built — at 17 well-known GitHub repositories and collected the data. Here's what I found. 🦀 Rust is quietly eating JavaScript tooling This was the biggest surprise. Three "JavaScript ecosystem" tools have significant Rust codebases: Project You'd think it's... Actually... Next.js JavaScript 13.5% Rust Tailwind CSS CSS/JS 16.0% Rust Deno JavaScript runtime 59.4% Rust Next.js — the React meta-framework — is 13.5% Rust . Tailwind CSS is 16% Rust . These aren't Rust projects. They're JavaScript tools that have quie