jsDelivr - Open Source CDN
Note: Our backend changed. Learn how to use the new jsDelivr
jsDelivr is a free CDN for open source files. We are tightly integrated with Github and npm allowing us to automatically provide a reliable CDN service to almost every open source project out there.
We offer a stable CDN that can be used in production on popular websites with huge amounts of traffic. There are no bandwidth limits or premium features and its completely free to use by anybody.
jsDelivr – The advanced open source public CDN
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 Fastly. In mainland China we use Quantil.
If a CDN goes down, websites that use jsDelivr won't have any issues because all traffic will be instantly redirected to remaining operational providers.
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.
Our load-balancing code is open source as well.
We have multiple layers of failover to protect our users from any downtime.
We use 2 DNS providers at the same time. NS1 and Route53. For jsDelivr to go down both of these companies would have to go down at the same time.
Both of our DNS providers monitor our load-balanced endpoint and if they detect problems they will automatically switch all traffic to a single CDN provider.
Our load-balancer monitors the uptime of all CDN providers using both RUM and synthetic data. If any of those detect downtime or performance degradation that CDN provider will be removed immediatly without any impact to our users.
Our origin consits of multiple servers in different data-centers. If a server goes down the CDNs will automatically switch to using the remaining healthy servers.
In total we have one of the most resilient systems out there, ready to be used in production by even the biggest companies.
All of our POPs support HTTP2, allowing performant transfers when possible.
jsDelivr has partnered up with multiple Chinese companies to provide fast and reliable file delivery in China mainland and the whole Asian continent. We have servers inside China that improve the delivery speeds and latency significantly. We also have a valid ICP license issued by the Chinese government that protects us from bans and slow downloads.
jsDelivr works perfectly inside China!
Our npm endpoint has the following format:
/npm/package@version/file
Load exact version:
/npm/[email protected]/dist/jquery.min.js
Use a version range instead of an exact version:
/npm/jquery@3/dist/jquery.min.js
/npm/[email protected]/dist/jquery.min.js
Load by tag: (Not recommended for production usage)
/npm/jquery@beta/dist/jquery.min.js
Omit the version completely or use "latest" to load the latest one: (Dev environment only)
/npm/jquery@latest/dist/jquery.min.js
/npm/jquery/dist/jquery.min.js
Add ".min" to any JS/CSS file to get a minified version - if one doesn't exist, we'll generate it for you. All generated files come with source maps and can be easily used during development:
/npm/[email protected]/github-markdown.min.css
Omit the file path to get the default file. This file is always minified:
/npm/[email protected]
/npm/jquery@3
/npm/jquery
Get a directory listing:
/npm/[email protected]/
/npm/[email protected]/dist/
Our Github endpoint has the following format:
/gh/user/repo@version/file
Load exact version:
/gh/jquery/[email protected]/dist/jquery.min.js
Use a version range instead of an exact version (only works with valid semver versions):
/gh/jquery/jquery@3/dist/jquery.min.js
/gh/jquery/[email protected]/dist/jquery.min.js
Omit the version completely or use "latest" to load the latest one (only works with valid semver versions): (Dev environment only)
/gh/jquery/jquery@latest/dist/jquery.min.js
/gh/jquery/jquery/dist/jquery.min.js
Add ".min" to any JS/CSS file to get a minified version - if one doesn't exist, we'll generate it for you. All generated files come with source maps and can be easily used during development:
/gh/sindresorhus/[email protected]/github-markdown.min.css
Get a directory listing:
/gh/jquery/[email protected]/
/gh/jquery/[email protected]/dist/
Our combine endpoint has the following format:
/combine/url1,url2,url3
All features that work for individual files (version ranges, minification, main modules) work here as well. All combined files come with source maps and can be easily used during development.
Examples:
/combine/gh/jquery/[email protected]/dist/jquery.min.js,gh/twbs/[email protected]/dist/js/bootstrap.min.js
/combine/npm/[email protected]/dist/css/bootstrap.min.css,npm/[email protected]/dist/css/bootstrap-theme.min.css
All packages hosted on npm and tagged releases on GitHub are automatically available on jsDelivr. If you are a package author, here are a few tips to make using your package as easy as possible:
- Use semver for versioning (this is enforced by npm but not by GitHub)
- If a file listed as
maininpackage.jsonisn't meant to be used in a browser, set abrowser,cdn, orjsdelivrfield - If you distribute minified JS/CSS files, also include source maps for those files
- If you don't want to provide minified files, it's fine - we'll handle that for you
For packages hosted on npm, we support serving "default" files with shorter URLs. The default file can be configured by setting one of the following fields in package.json, with jsdelivr having the highest priority:
jsdelivrcdnbrowsermain
Our wordpress endpoint has the following format:
/wp/project/tags/version/file
Load exact version:
/wp/wp-slimstat/tags/4.6.5/wp-slimstat.js
Load latest version: (Dev environment only)
/wp/wp-slimstat/trunk/wp-slimstat.js
We can work together and setup a custom configuration for your project. This way, you can have full control over your files 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 [email protected] with a request for more information.
Current OSS projects using custom configs:
- webjars
- webpack webpackbin and codesandbox
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.
<script async src="//radar.cedexis.com/1/11475/radar.js"></script>