unpkg/modules/client/main/About.md

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unpkg is an open source project built and maintained by Michael Jackson.

Sponsors

The fast, global infrastructure that powers unpkg is generously donated by Cloudflare and Heroku.

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 is given. Redirects are cached for 5 minutes.

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

Support

unpkg is a free, best-effort service and cannot provide any uptime or support guarantees.

I do my best to keep it running, but sometimes things go wrong. Sometimes there are network or provider issues outside my control. Sometimes abusive traffic temporarily affects response times. Sometimes I break things by doing something dumb, but I try not to.

The goal of unpkg is to provide a hassle-free CDN for npm package authors. It's also a great resource for people creating demos and instructional material. However, if you rely on it to serve files that are crucial to your business, you should probably pay for a host with well-supported infrastructure and uptime guarantees.

unpkg is not affiliated with or supported by npm, Inc. in any way. Please do not contact npm for help with unpkg.

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!

Feedback

If you think this is useful, we'd love to hear from you. Please reach out to @unpkg with any questions or concerns.