evanw/esbuild

esbuild is a JavaScript bundler and minifier that is dramatically faster than the tools that preceded it. The problem it solves is that build steps in JavaScript projects, turning many source files into a single optimized bundle for the browser, had become painfully slow. Tools like webpack and Parcel, while feature-rich, can take seconds or even minutes to complete a build on large projects. esbuild does the same job in milliseconds. The speed comes from writing esbuild in Go rather than JavaScript, which allows it to take full advantage of multiple CPU cores and avoids the overhead of running in a JavaScript runtime. esbuild natively handles JavaScript, TypeScript, JSX, and CSS, so most projects need no plugins for basic bundling. It supports both ESM and CommonJS module formats, does tree shaking to remove unused code, can minify output to reduce file size, generates source maps for debugging, includes a local development server, and has a watch mode that rebuilds when files change. A straightforward API is available via the command line, as a JavaScript package, and as a Go library. You would use esbuild when you want fast builds in a JavaScript or TypeScript project, whether for a library you're publishing, a web application you're deploying, or as the underlying bundler powering another tool. Many popular frameworks and tools use esbuild internally for its speed while adding their own higher-level features on top. The tech stack is Go for the core bundler, with thin JavaScript and Go API wrappers that let you call it from either language.