Rolldown vs Rspack

Rolldown is a free, open-source JavaScript bundler written in Rust and designed as the unified bundler powering Vite 8+. Its Rollup-compatible plugin API can reuse most existing Rollup plugins. Built-in capabilities include TypeScript and JSX transforms, syntax lowering, module resolution, ESM and CommonJS interoperability, define, inject, and minification. It can handle mixed ESM and CommonJS module graphs and supports configurable manual code splitting. Install commands are provided for npm, pnpm, yarn, bun, and vp. Prebuilt binaries are listed for Linux, Windows, Apple platforms, Android, and other targets; where none is distributed, a Wasm build or building from source are options. The guide recommends using Rolldown through Vite for most applications and points library authors to tsdown. Module types are experimental, and the JavaScript build() API may change in patch releases. The troubleshooting guide says Windows file-system access can slow builds, particularly when transforms run without plugins. An online REPL is linked, along with GitHub, Discord, and contribution resources. VoidZero Inc. holds the copyrights, funds development, and directs the project; it states Rolldown remains open source and MIT-licensed.

Rspack is a free, open-source bundler for web projects, built with Rust and TypeScript. Its parallelized architecture supports parallel builds, while incremental compilation is used to improve hot module replacement. Rspack updates the webpack API with the aim of supporting webpack replacement, but it does not promise full API compatibility; it prioritizes commonly used APIs and adds others based on user needs. It works with almost all community loaders, and over 85% of the 50 most downloaded webpack plugins can be used with it or have an alternative. Built-in capabilities include code splitting, tree shaking, asset management, a development server, SWC, Lightning CSS, and a JavaScript build API. Documented integrations cover React, React Server Components, Preact, Vue, Next.js, Node.js applications, NestJS, Solid, Svelte, and Rstest. Custom plugins and loaders can be written in JavaScript or Rust. Rspack 1.0 was released in August 2024 and is described as production-ready. It is available for Linux, macOS, and Windows, as well as web and self-hosted environments. The software is released under the MIT license; questions can be directed to Discord or GitHub Discussions.