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).
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!
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.