Rolldown Config Builder

Rolldown is a next-generation JavaScript bundler built with Rust and the oxc (Oxidation Compiler) toolkit. It is designed to be the eventual replacement for Rollup inside Vite, delivering near-identical output semantics but dramatically faster build times due to Rust's multi-threaded processing and zero-cost abstractions.

Rolldown is designed to be API-compatible with Rollup. It supports the same plugin API (Rollup plugin hooks) and produces equivalent output. The key difference is speed: Rolldown is typically 10-100x faster than Rollup on large codebases because it runs in Rust instead of JavaScript. Rolldown also has built-in tree-shaking and code-splitting.

esbuild is a fast bundler written in Go, optimised for speed over output fidelity. Rolldown is written in Rust and designed to produce webpack/Rollup-quality output (advanced tree-shaking, fine-grained code-splitting, full ESM semantics). Choose esbuild for simple, ultra-fast bundles; choose Rolldown when you need Rollup-level correctness and plugin compatibility.

Rolldown is best suited for: library authors who want Rollup-compatible output at higher speed; teams planning to migrate to Vite 6+ (which will use Rolldown internally); projects that rely on Rollup plugins and want to keep that ecosystem while gaining Rust speed. For application bundling today, Vite (Rolldown-based) is the recommended path.

Rolldown supports ESM (esm), CommonJS (cjs), IIFE (iife), UMD (umd), and AMD (amd) formats. ESM is the modern default for libraries and browser modules. CJS is required for Node.js compatibility. IIFE/UMD are useful for browser scripts loaded via a script tag.

Install with: npm install rolldown. Then create rolldown.config.js and run npx rolldown. Note that Rolldown is still under active development and stabilizing its API. For production use, check the current release status on the rolldown.rs website.