About Bundlephobia
Bundlephobia shows what an npm package will add to your frontend bundle before you install it. It helps you judge whether a library is worth its size.
What it does
Search for a package name and the site reports its size, along with the dependencies that come with it. It also breaks down the exports, so you can see what importing one part of a library really costs. Sizes are shown in minified and gzipped form.
Key features
- Size of a package and its impact on the bundle
- Breakdown of dependencies and exports
- Scan a package.json file (beta)
- Badges that show package size for a README
- MCP option for AI tools
Who it's for
Frontend developers choosing libraries, performance engineers tracking bundle growth and tech leads who want to set guidelines for dependencies.
Pricing and good to know
Bundlephobia is open source under the MIT license and free to use. The site is hosted by its author, and the code is public on GitHub for anyone who wants to check it or contribute. Sizes measure a package's build output, so tree shaking and your own bundler settings can change the real impact in your app.
Highlights
- Size of a package and its impact on the bundle
- Breakdown of dependencies and exports
- Scan a package.json file (beta)
- Badges that show package size for a README
- MCP option for AI tools
