A free Open Source CDN for webmasters and developers

jsDelivr - Open Source CDN

Similar to Google Hosted Libraries, jsDelivr is an open source CDN that allows developers to host their own projects and anyone to link to our hosted files in their websites.

We offer a stable CDN that can be used in production even on popular websites with huge amounts of traffic. There are no bandwidth limits or premium features and its completely free to use by anybody.

All kinds of files are allowed, including JavaScript libraries, jQuery plugins, CSS frameworks, fonts and more.

You can use this repo to make your own changes and improve the contents of jsDelivr’s CDN. Feel free to open issues and pull requests if you think something should be changed.

All changes made to this repo are synced to the CDN. It can take a few minutes for the changes to appear on the website.

jsDelivr – The advanced open source public CDN

How jsDelivr works (outdated)

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Why jsDelivr?

Performance and Uptime Oriented

Our public CDN is built with performance and reliability in mind. Everything is optimized and being constantly improved to offer all users maximum speed and uptime. Performance is monitored at all times, and we are always looking into new technologies and providers that may further improve our CDN.

Downtime, timeouts or slow responses are simply unacceptable. The idea is not to simply offer a public CDN, but to offer the best possible experience and a rock-solid product.


Unlike the competition, jsDelivr uses multiple CDN providers, resulting in the best possible uptime and performance. We currently use MaxCDN, CloudFlare, and KeyCDN.

On top of CDN providers, jsDelivr also utilizes custom servers in locations where CDNs don’t have points of presence to further optimize the speed of file downloads for users near those locations.

If a CDN or custom server goes down, websites that use jsDelivr won’t have any issues because all traffic will be instantly redirected to remaining operational providers.

Smart Load Balancing

jsDelivr uses Cedexis with real user performance data (also known as RUM) to make its routing decisions. These metrics are gathered from hundreds of websites and are used in our load balancing algorithm to make accurate decisions for serving content.

All providers (CDNs and custom servers) are tested millions times per day by real users from all over the world. Based on this information, jsDelivr knows what provider is the fastest for each user. Each user gets a unique response based on his or her location, ISP, and the providers’ uptime in real time.

This system also responds immediately to performance degradation and downtime of providers. If a CDN is under a DDoS attack, and their performance drops in some locations, in matter of seconds the algorithm will pick up the change and start serving a different provider to all affected users.


All of our POPs support SPDY loading, allowing performant transfers when possible.

How to submit or update projects

Refer to CONTRIBUTING.md for instructions on how to add a new project to jsDelivr.


jsDelivr can automatically keep a project up-to-date as new versions are released. Configuration is fast and easy: All you need to enable this feature for a project is to create an update.json file in its root directory along with the info.ini.

Example (/files/humane.js/update.json):
  "packageManager": "github",
  "name": "humane.js",
  "repo": "wavded/humane-js",
  "files": {
    "include": ["humane.min.js", "humane.js", "./themes/**/*"]

Full documentation is available here.


URL Structure

Typical usage:
Example: //cdn.jsdelivr.net/jquery/1.11.0/jquery.min.js

When you want all the files in that version folder as a single compressed archive:

Downloads the three projects’ mainfile from their latest versions as a single collated file:

You may specify a specific version or version-branch per file:

You may also select more than one file from a project (typically for plug-ins that ship with the project):

Version aliasing

For latest version use:


You can also load latest versions per branch:

//cdn.jsdelivr.net/{projectName}/3.8/{file} Latest in 3.8 branch

//cdn.jsdelivr.net/{projectName}/3/{file} Latest in 3 branch

To automatically load the main file of a project use:


Depending on the project, jsDelivr will automatically load the main file as configured in info.ini with correct MIME HTTP headers. If no mainfile parameter was specified, the request will result in 404 error.

Load multiple files with single HTTP request

Load multiple projects using the lastest version of the main file:


Load version 3.8.15 of the main file for abaaso and the latest version of the main file for the other projects:

//cdn.jsdelivr.net/g/[email protected],ace,alloyui

Load the latest version of the main file for all files and for abaaso loads version branch 3.8 (e.g. version 3.8.16):

//cdn.jsdelivr.net/g/[email protected],ace,alloyui

To combine multiple files enter the relative paths to all files you want to load inside brackets () separated by a plus + symbol. Brackets can be encoded as %28 and %29 without issues.

Load multiple files from multiple projects:

//cdn.jsdelivr.net/g/[email protected],[email protected](angular.min.js+angular-resource.min.js+angular-animate.min.js+angular-cookies.min.js+angular-route.min.js+angular-sanitize.min.js)

As always it supports version aliasing and latest versions:

//cdn.jsdelivr.net/g/jquery,[email protected](angular.min.js+angular-resource.min.js+angular-animate.min.js+angular-cookies.min.js+angular-route.min.js+angular-sanitize.min.js)


Now if all files in the combination have a .css extension then the server will automatically respond with Content-Type: text/css header. In all other cases the server responds with Content-Type: application/javascript header.

//cdn.jsdelivr.net/g/[email protected](angular-ui.min.css),[email protected]

The first 3-4 requests will be slower, as they are not yet cached. Afterwards, these dynamic files get cached and become static files (same as all others).


jsDelivr has a fully featured API that also supports Google Hosted Libraries and cdnjs


npm jsdelivr

An npm module that can be used in your node.js applications:

More coming soon…

Custom CDN Hosting

If your project does not qualify to be hosted in GitHub or you need direct access to your files, it’s not a problem! We can work together and setup a custom configuration for your project. This way, you can have full control over your files, without the restrictions of GitHub, and the ability to utilize the full power of jsDelivr.

This kind of custom hosting can be suitable for:

  • Binary hosting. Windows executable files and zips.
  • Frequently updated files.
  • Projects that can’t follow jsDelivr file structure.
  • Some other use that will blow all of our minds.

Simply send an email to jimaek with a request or for more information.

jsDelivr is here to help and not to limit. Even if what you need is not listed above, feel free to contact us.

Contribute Performance Data

jsDelivr uses real user performance data (also known as RUM) to make its routing decisions. This data is gathered from hundreds of websites and is used in our load balancing algorithm to make accurate decisions based on real time performance metrics.

This is why we offer the ability to all users to help us out. This data is very important and we encourage all users to participate.

All you have to do is include the following JavaScript code in your website before </body>. This code is then executed each time a user visits your website. It uses their browser to test the latency to our CDN providers and gather performance and availability metrics.

These benchmarks are completely transparent to the user and do not impact on browsing in any way. We store the following information:

  • Performance metrics to each of our providers.
  • Availability metrics to each of our providers.
  • Browser’s User-Agent
  • First three octets of the user’s IP address

Our JS code is executed with a 2 second delay and tests all of our providers unless interrupted. This testing does not impact on your website performance or user browsing experience.

(function(a,b,c,d,e){function f(){var a=b.createElement("script");a.async=!0;
a.src="//radar.cedexis.com/1/11475/radar.js";b.body.appendChild(a)}/\bMSIE 6/i

Alternatively you can also include it in a /g/ combined URL. Simply add jsdelivr-rum at the end to include our javascript. For example:

http://cdn.jsdelivr.net/g/[email protected],jsdelivr-rum

Privacy Policy for Data Contribution

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