Parcel vs Rslib

Parcel is a free, open source, zero-configuration build tool for web projects. It handles HTML, CSS, JavaScript, TypeScript, JSX, Flow, images, fonts, videos, Sass, SVG, Vue, Node, Electron, GraphQL, MDX, XML and other file types out of the box. It can automatically install plugins and development dependencies for additional file types. For development, Parcel includes an HTTPS server with an API proxy and automatically updates code in the browser, with React Fast Refresh and Vue hot-reloading integrations. Terminal and browser diagnostics include syntax-highlighted code frames, hints and documentation links. Production features include tree shaking, minification, image optimization, code splitting, content hashing, and Gzip and Brotli compression. Builds use worker threads and caching, with lazy development builds also supported. Parcel can target declared browser environments, handle workers, build libraries for multiple targets and build monorepos with one command. A plugin system and programmatic API support customization and integration into existing build systems. Its development server builds only one target at a time and defaults to a modern browser target; compression is not enabled by default.

Rslib is a free, open-source tool for developing JavaScript packages and UI component libraries. Based on Rsbuild and powered by Rspack, it integrates Rust-based tools including SWC and Lightning CSS. It supports bundle and bundleless build modes and outputs ESM, CJS, UMD, Module Federation, and IIFE formats. Framework integrations support component libraries for React, Vue, Svelte, and Solid. Rslib can generate TypeScript declaration files, including isolated declarations, though declaration generation is not enabled by default. Plugin support includes Rsbuild, Rspack, and webpack plugins. Its development integrations include Rstest for testing, Storybook for component development, Rspress for documentation and component previews, and Rsdoctor for build analysis. The quick-start guide lists Node.js, Deno, and Bun as runtime options, while Rslib v1 requires Node.js 20.19+ or 22.12+. It is available for API, Linux, macOS, web, and Windows, and is released under the MIT license.