Updated
cdnjs is a free content delivery network for open-source libraries. It serves JavaScript, CSS and font files from Cloudflare's network.[1]
cdnjs is a free, open-source, and community-driven distributed JavaScript library delivery service. It hosts a vast collection of popular JavaScript and CSS libraries, allowing developers to easily include these resources in their web projects without hosting them locally. cdnjs offers high availability and performance through its global CDN infrastructure, reducing load times and bandwidth usage for websites. It supports version control, allowing developers to specify exact library versions, and provides both HTTP and HTTPS access. The service is maintained by volunteers and supported by sponsors, making it a reliable and cost-effective solution for web developers worldwide.
cdnjs belongs toCDNcategory.
248websites
use it — 9.7% of the 2,560 websites we scanned in the last 12 months
#4of 29
tools in its category seen in our scans (we recognize 69)
103public pages
on UptimeCard — open any of them to see how that site is doing
In short: a free, community-run source for popular open-source libraries on Cloudflare's network. Pin the library version in the URL you copy.[1]
11.84% of all websites we track run cdnjs▼ 0.01 points since 20 Sep
cdnjs next to jsDelivr
Statements come from each vendor's own home page; website counts are ours.
| cdnjs |  jsDelivr | |
|---|---|---|
| What the vendor says | ||
| Price | Free[1] | Free[2] |
| Where files come from | Open source librariesJavaScript, CSS and fonts[1] | npm and GitHub[2] |
| What we see in our scans | ||
| Websites running it | 2489.7% of 2,560 scanned sites | 32212.6% of 2,560 scanned sites |
| Typical page load time | 4.6 s✓97 public sites | 4.7 s151 public sites |
| Typical page weight | 3.9 MBtypical home page | 3.6 MB✓typical home page |
| Security grade B or better | 21%7 of 34 graded sites score B or better | 29%✓12 of 42 graded sites score B or better |
Each row shows what the vendor says about itself.
- jsDelivr: Another free CDN for open-source projects, serving npm and GitHub files[2]
How cdnjs sites protect themselves
Share of the 248 sites we scanned that run each protection
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS
reCAPTCHA28% · 70 sitesreCAPTCHA is a free service from Google that helps protect websites from spam and abuse
Protections add up, they do not replace each other: a site can run all of them.
What sites use cdnjs for
An estimate from UptimeCard's technology map of 89 public sites
amity.co · appspace.com · articulatestatus.com
aic.status.akamai.com · buildkitestatus.com · hackeronestatus.com
opengov.com
granicus.com
Rough guide, not a measurement: each description is written automatically from the site’s technology stack and the site has not confirmed it. A site is counted once, in the first group its description fits (shop, help and docs, blog, marketing site; otherwise the whole site). Descriptions that only guess (“likely”, “may”) are left out.
At a glance
UptimeCard's own scans and tests of 2,560 websites · refreshed weekly
How cdnjs sites scoreout of 100 · hover or tap a score for details
Page load time
Loads about as fast as the average site
Most cdnjs sites load in 3.5–7.2 s. Home page weight: 3.9 MB vs 3.3 MB for all sites. 97 public sites measured.
Where are they hosted?
Mostly Cloudflare and Amazon Web Services
- Cloudflare34%
- Amazon Web Services26%
- Google Cloud7%
- Fastly6%
- Other27%
Who uses it?
Software as a Service (SaaS) sites use cdnjs 1.5× more than average
Share of 103 classified public sites. “× average” compares with all 961 public sites.
Browser-security check
21% of graded sites pass
7of 34 score B or better
Rates each site’s own security settings, not cdnjs. 34 public sites graded so far.
How cdnjs sites are built
Closest partners. The number says how many times more often the tool runs on cdnjs sites than on an average website. Hover a partner for its share of sites.
Font Awesome4×
jQuery CDN4×
Slick4×jsDelivr3×
Bootstrap3×
Google Hosted Libraries3×
Microsoft Clarity2×Stacks we see most. Tools that tend to run together with cdnjs on the same websites. The percentage is the share of all 248 cdnjs sites that run the whole stack.
cdnjs + Bootstrap + WordPress + Yoast SEO + Contact Form 7
cdnjs + jsDelivr + Bootstrap + Unpkg
cdnjs + jsDelivr + Google Hosted Libraries + Webflow
cdnjs + WordPress + GSAP
cdnjs + Google Hosted Libraries + GSAP
cdnjs + Bootstrap + Atlassian Statuspage
cdnjs + Bootstrap + jQuery CDN + Animate.css
cdnjs + WordPress + Google Hosted Libraries
cdnjs + Google Hosted Libraries + jQuery CDN
cdnjs + WordPress + Unpkg
cdnjs + jsDelivr + Cookiebot
cdnjs + jsDelivr + Microsoft ASP.NET
Usually installed alongside
The bigger the bubble, the more of the 248 cdnjs sites also run the tool. Colour shows what the tool does. Hover or tap a bubble for details.
Google Analytics73%
Facebook Pixel29%
Linkedin Insight Tag22%
Google Tag Manager72%
Microsoft Advertising18%
DoubleClick Floodlight16%
OneTrust17%
HubSpot14%Yoast SEO13%Similar tools in its category
CDN: 69 tools known, 29 seen in our scans
Amazon CloudFront335 sitesAlternative
Akamai205 sitesAlternative
Amazon S3184 sitesAlternative
Google Cloud CDN82 sitesAlternative
Netlify58 sitesAlternative
Imperva46 sitesAlternative
Hostinger CDN22 sitesAlternative
Bunny16 sitesAlternative
Cloudflare1,038 sitesUsed togetherjsDelivr322 sitesUsed togetherGoogle Hosted Libraries145 sitesUsed togetherUnpkg106 sitesUsed togetherHow websites combine cdnjs with other tools
Relationships found on the websites that use it, from the same map status pages show.
Questions about cdnjs
- Is cdnjs free?
- Yes. It describes itself as the free CDN for open-source libraries.[1]
- What network does it run on?
- cdnjs is powered by Cloudflare and caches files on Cloudflare's network.[1]
- Can I contribute?
- Yes. The project is open on GitHub and accepts contributions.[1]
- How many websites use cdnjs?
- We found cdnjs on 248 of the 2,560 websites we scanned in the last 12 months (9.7%). 103 of them have a public status page.
- What is cdnjs often used with?
- Among the websites we scan, cdnjs is often found alongside Google Analytics (73% of its sites), PHP (41.5% of its sites), jsDelivr (39.1% of its sites).
- What are the alternatives to cdnjs?
- Other CDNs we recognize include Cloudflare, Amazon CloudFront, jsDelivr, Akamai.
Is your website built with cdnjs?
UptimeCard checks it around the clock, tells you the minute it stops answering, and gives your visitors a status page.