Parcel

Parcel is a free and open-source web application bundler designed to simplify building web applications. It bundles JavaScript, HTML, CSS, and a variety of asset types into optimized bundles for the browser. Parcel emphasizes zero-configuration usage; it infers project structure and transformations from the files present and installed plugins, reducing the need for explicit configuration. Core ideas include constructing a dependency graph, applying transformations via a plugin system, performing code splitting, and producing production and development builds with minimal setup. Parcel supports a wide range of file types out of the box and can be extended with plugins to add new transformers, optimizers, and runtimes.

Key features include a built-in development server with hot module replacement, automatic installation of missing dependencies, fast incremental rebuilds through caching and parallel processing, and automatic asset hashing for long-term caching. Parcel also supports modern JavaScript features, TypeScript, CSS preprocessors, and popular frameworks via plugins. It aims to provide a straightforward workflow from source code to deployable bundles, while remaining extensible enough for more complex projects.

The project is maintained as an open-source initiative with contributions from a community of developers and is commonly used in both small experiments and larger applications. For comparison, other bundlers include Webpack and Rollup. Note: the word parcel can also refer to a package in logistics; this article focuses on the software tool.