esbuild: JavaScript bundler 100 times faster

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The bundling bottleneck

Webpack, Rollup, Parcel are written in JavaScript and run single-threaded. Builds of large frontend projects take 30s-5min. During development, hot-reload of every change adds latency. A paradigm shift is needed.

The release

esbuild is published in January 2020 by Evan Wallace, cofounder and CTO of Figma, as a side project. Version 0.12 (June 2021) marks API stabilisation. Written in Go, MIT licence. Parallel-first, zero JS dependencies.

Features

• Extreme speed — 10-100× faster than Webpack/Rollup
• TypeScript stripping (not type-checking)
• JSX transform
• Aggressive tree shaking
• Code splitting and lazy loading
• ESM + CommonJS output
• Built-in minification (Terser alternative)
• Source maps
• Plugin API for custom extensions
• CLI, JS API (Node), Go API

esbuild app.tsx --bundle --minify --outfile=out.js

Typical benchmarks

Build of a 10,000 module React app:

• Webpack: ~40s
• Rollup: ~30s
• Parcel 2: ~15s
• esbuild: ~0.5s

Use as dependency

esbuild is not only used standalone, but as foundation of:

• Vite — dev server and pre-bundle with esbuild, production with Rollup
• tsup — TypeScript library bundler
• Bun — uses esbuild-like core
• Next.js — SWC/esbuild in parts
• Remix — pre-build
• Snowpack — legacy
• Sveltekit — bundling
• Astro — part of toolchain

Limits

• No TypeScript type-checking — needs separate tsc --noEmit
• Small plugin ecosystem vs Webpack
• Basic CSS handling (via PostCSS plugin)

Competitors

• SWC (2019) — Rust, similar speed, used in Next.js
• Rollup (2015) — standard for libraries
• Turbopack (2022, Vercel) — Rust-based webpack successor, for Next.js
• Rspack (2023, ByteDance) — Rust, Webpack-compatible
• Parcel 2 (2021) — swc + native

In the Italian context

esbuild is omnipresent in modern Italian frontend projects, usually indirectly via Vite, Astro, Next.js. Directly used by:

• Italian library maintainers (tsup)
• TypeScript monorepos (Turborepo)
• CI pipelines requiring fast builds
• Serverless deployment (Lambda, Cloudflare Workers)

The impact has been seismic: median build times of React projects went from minutes to seconds post-esbuild adoption (via Vite).

References: esbuild (Evan Wallace, Figma, January 2020). 0.12 stabilisation (June 2021). MIT licence. Written in Go. Used as foundation in Vite, tsup, Bun. Competitors SWC (Rust), Turbopack, Rspack.