Rolldown

Rolldown is a Rust-based, free and open-source bundler for JavaScript, 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 supports mixed ESM and CommonJS module graphs, as well as 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; users without a distributed binary can use the Wasm build or build from source. The guide recommends using Rolldown through Vite for most applications and points library authors to tsdown. Module types are documented as experimental, and the JavaScript build() API may change in patch releases. Its troubleshooting guide notes that Windows file-system access can slow builds, especially when transforms run without plugins. An online REPL and community links are available.

Rolldown provides JavaScript bundling with a Rollup-compatible plugin API and built-in transforms. Note its experimental module types and build() API caveat, and consider the project's recommended routes for applications and libraries.

Rolldown may suit JavaScript developers, especially those using Vite or reusing Rollup plugins. The project points library authors to tsdown.

Overview

Rolldown is a Rust-based JavaScript bundler for developers who want a Rollup-compatible plugin API and built-in transforms. Its strongest fit is work in the Vite ecosystem; application teams should generally reach it through Vite rather than adopt it directly.

It is free and open source under the MIT license, with development funded and directed by VoidZero Inc. A browser-based REPL offers a way to explore it, while GitHub, Discord and contribution resources support people working with the project.

Key features

Rolldown’s plugin API matches Rollup’s, so projects can reuse most existing Rollup plugins instead of rebuilding their plugin setup from scratch. That is a practical advantage for teams already invested in Rollup, though it does not promise compatibility with every plugin. Community plugins published to npm are listed in the Vite Plugin Registry.

Built-in TypeScript, JSX and syntax-lowering transforms are powered by Oxc. The bundler also provides module resolution, ESM/CommonJS interoperability for mixed module graphs, define and inject options, minification, tree shaking and source maps. Manual code splitting is configurable, which gives teams control over chunk organization without requiring a separate CommonJS plugin for mixed graphs.

Module types remain experimental, making them a poor foundation for production workflows that depend on a settled interface. Rolldown also offers JavaScript APIs for bundling, watching and building, but its build() API is experimental and may change in patch releases. Teams using that API directly should be prepared to adapt as it evolves.

Pricing

Rolldown’s Free & open source plan costs nothing. The free plan includes the bundler under the MIT license, with no paid plans stated. There are no published seat or usage quotas to weigh against a paid tier, so it suits individual developers and teams seeking an open-source build tool without a subscription.

Platforms

Install commands are provided for npm, pnpm, yarn, bun and vp. Prebuilt binaries cover Linux, Windows and Apple platforms, with additional targets including Android, FreeBSD, OpenHarmony and Wasm/Wasi variants. Where a prebuilt binary is unavailable, the Wasm build or a source build provides another route.

Windows file-system access can slow builds, particularly when transforms run without plugins. Windows users should account for that limitation when evaluating build performance. The troubleshooting guide also cautions that direct eval can let bundled code access variables from other files; if those variables contain sensitive data, that access can create a security issue.

Who it's for

Rolldown is most compelling for developers building within Vite’s direction or maintaining Rollup-based workflows who want compatible plugins alongside built-in transforms. The project recommends using it through Vite for most applications and points library authors to tsdown, so direct adoption is less suitable for teams looking for the recommended application or library workflow.

Pros and cons

• Pro: A Rollup-identical plugin API lets teams reuse most existing Rollup plugins, reducing migration friction.
• Pro: Built-in TypeScript, JSX and syntax lowering, plus mixed ESM/CommonJS support, cover common bundling needs without a collection of separate plugins.
• Pro: Free, open-source MIT licensing avoids subscription costs and paid-tier tradeoffs.
• Con: Experimental module types and the experimental build() API bring interface uncertainty for production-critical projects.
• Con: Windows file-system access may slow builds, especially when transforms run without plugins.
• Con: Direct use of eval can expose variables across files, which is a security concern when they hold sensitive data.

Alternatives

JavaScript Build Tools is the broader category to browse when you want to compare options across the space.

Choose SWC instead if you want a free, open-source Rust-based developer toolchain rather than Rolldown’s bundler-centered fit.

esbuild is another free option, with native executable and WebAssembly versions and no paid tiers stated; consider it when those formats suit your deployment needs.

Google Closure Compiler is a free, open-source Java application, Bazel library and NPM package, making it an alternative for readers seeking those distribution forms.

Choose Oxc instead if a free, open-source option from the same technology family is what you need, rather than a JavaScript bundler.

Rspack is a free MIT-licensed alternative to consider when you want another open-source build tool.

Vite is the natural alternative for application teams: Rolldown’s makers recommend using Rolldown through Vite for most applications.

webpack offers a free, MIT-licensed self-managed option if you prefer that model.

Parcel is another open-source project, supported by code and financial contributions from companies and individuals.

Verdict

Choose Rolldown if you want a free Rust-based bundler with Rollup plugin compatibility, built-in transforms and configurable code splitting, especially for work in the Vite ecosystem. Look elsewhere—or use it through Vite—if you need stable experimental APIs, a recommended library workflow, or predictable Windows file-system performance.