Rollup
Rollup is a JavaScript module bundler for turning smaller pieces of code into applications or libraries.
What Rollup is
Rollup is a JavaScript module bundler for turning smaller pieces of code into applications or libraries. It supports output formats including ES modules, CommonJS, UMD, AMD, IIFE, and SystemJS, with builds for browsers and Node.js. Rollup analyzes imported code and removes portions that are not used, a process known as tree-shaking. It can also split code across entry points and dynamic imports using the output format’s import mechanism. Developers can configure inputs, outputs, plugins, tree-shaking, and watch mode, and use either its command-line interface or JavaScript API. A plugin API supports code injections and transformations; existing CommonJS modules can be imported through a plugin. The documentation includes a browser REPL that accepts ES6 modules and offers several output format choices. The project notes that Vite pre-configures Rollup with defaults and plugins, and that WMR adopted its plugin API. Rollup is free under the MIT License, and the project recommends keeping Rollup and its official plugins current.
Good
- Supports multiple JavaScript output formats.
- Tree-shaking removes unused imported code.
- Offers a command-line interface and JavaScript API.
- Browser REPL accepts ES6 modules.
- Released under the MIT License.
Watch out
- No free trial is listed.
- CommonJS imports require a plugin.
Who it suits
Rollup suits JavaScript developers building applications or libraries, including projects targeting browsers or Node.js. It also fits workflows that need configurable output formats, code splitting, or a plugin API.
Verdict
Rollup provides configurable bundling, tree-shaking, code splitting, and a plugin API for JavaScript projects. Its browser REPL offers a way to work with ES6 modules in a browser.
The facts
Each one read from Rollup's own pages, with the date it was checked.
Where it runs
- Browser REPL
- Rollup provides a browser REPL that accepts ES6 modules and offers output format choices including ES, AMD, CJS, IIFE, UMD, and System.checked 4 Oct 2026
- Browser use
- The documentation includes a page for running Rollup in a browser, and the site links to an online REPL.checked 4 Oct 2026
What it does
- Code formats
- Rollup can output formats including ES modules, CommonJS, UMD, AMD, IIFE, and SystemJS.checked 4 Oct 2026
- Code splitting
- It can split code across entry points and dynamic imports using the output format’s import mechanism.checked 4 Oct 2026
- Compatibility
- Rollup can import existing CommonJS modules through a plugin.checked 4 Oct 2026
- Configuration
- Rollup provides configuration options for inputs, outputs, plugins, tree-shaking, and watch mode.checked 4 Oct 2026
- Integrations
- The site says Vite pre-configures Rollup with defaults and plugins, and names WMR as a project that adopted its plugin API.checked 4 Oct 2026
- Interfaces
- Rollup can be used from a command line interface or through its JavaScript API.checked 4 Oct 2026
- License
- Rollup is released under the MIT License.checked 4 Oct 2026
- Output formats
- It supports output formats including ES modules, CommonJS, UMD, and SystemJS.checked 4 Oct 2026
- Plugins
- Rollup provides a plugin API for code injections and transformations.checked 4 Oct 2026
- Purpose
- Rollup is a JavaScript module bundler that compiles small pieces of code into larger applications or libraries.checked 4 Oct 2026
- Security
- The project asks users to report vulnerabilities through a private GitHub vulnerability report and recommends using the latest Rollup and official plugin versions.checked 4 Oct 2026
- Security guidance
- The security page recommends using the latest versions of Rollup and its official plugins.checked 4 Oct 2026
- Security reporting
- The project asks vulnerability reporters to submit a private vulnerability report through GitHub Security.checked 4 Oct 2026
- Support
- The Rollup site links to a chat channel and to Open Collective for project contributions.checked 4 Oct 2026
- Tree-shaking
- Rollup statically analyzes imported code and excludes parts that are not used.checked 4 Oct 2026
- Use cases
- The project describes Rollup as suitable for building libraries and applications, including builds targeting browsers and Node.js.checked 4 Oct 2026
