unpkg is an [open source](https://github.com/unpkg) project built and maintained by [Michael Jackson](https://twitter.com/mjackson).

### Sponsors

The fast, global infrastructure that powers unpkg is generously donated by [Cloudflare](https://www.cloudflare.com) and [Heroku](https://www.heroku.com).

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    <a href="https://www.cloudflare.com"><img src="CloudflareLogo.png"></a>
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  <div class="about-logo">
    <a href="https://www.heroku.com"><img src="HerokuLogo.png"></a>
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### Cache Behavior

The CDN caches files based on their permanent URL, which includes the npm package version. This works because npm does not allow package authors to overwrite a package that has already been published with a different one at the same version number.

URLs that do not specify a package version number redirect to one that does. This is the `latest` version when no version is specified, or the `maxSatisfying` version when a [semver version](https://github.com/npm/node-semver) is given. Redirects are cached for 5 minutes.

Browsers are instructed (via the `Cache-Control` header) to cache assets for 4 hours.

### Abuse

unpkg maintains a list of packages that are known to be malicious. If you find such a package on npm, please let us know!

### Support

unpkg is not affiliated with or supported by npm, Inc. in any way. Please do not contact npm for help with unpkg. Instead, please reach out to [@unpkg](https://twitter.com/unpkg) with any questions or concerns.