The State of Web Vitals

Main CDN

Which CDN, if any, serves the HTML document itself.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Desktop field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for Main CDN

Which CDN, if any, serves the HTML document itself.

7
Categories
94,906 sites
76.4%
Top share
origin
0.03
Top CLS
Median for origin

76.4% of HTML documents are served without a CDN.

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
2

Main CDN who uses what, and how stable each group is

Median CLS
0
0.05
0.10
0.15
0.20
0.25
fastly0.024% of sites
vercel0.021% of sites
origin0.0376% of sites
cloudflare0.0313% of sites
akamai0.033% of sites
netlify0.040% of sites
cloudfront0.053% of sites
VariantShare of sitesMedian
fastly 3,357 sites
4%
0.02
vercel 538 sites
1%
0.02
origin 72,501 sites
76%
0.03
cloudflare 12,431 sites
13%
0.03
akamai 2,663 sites
3%
0.03
netlify 175 sites
0%
0.04
cloudfront 3,241 sites
3%
0.05

Fastly sites post the best median CLS (0.02). Cloudfront sites trail at 0.05. Correlation, not causation. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
3

Passing CLS per main CDN which group passes the CLS most often

VariantSitesPassing CLSCLS
Vercel 0.6% 538 81% 0.02
Cloudflare 13.1% 12,431 80% 0.03
Akamai 2.8% 2,663 80% 0.03
Origin 76.4% 72,501 78% 0.03
Fastly 3.5% 3,357 78% 0.02
Cloudfront 3.4% 3,241 73% 0.05
Netlify 0.2% 175 72% 0.04
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site

81% of Vercel sites pass CLS. Netlify trails 9 points behind, leaving 28% of its sites failing. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
4

Why this matters for the Core Web Vitals, and where to start fixing it

Everything starts after the HTML arrives. The document's TTFB sits under every other phase: the browser cannot discover, download or render anything before it has the markup. Serving the document through a CDN terminates TLS close to the visitor, and when the HTML is edge-cached it removes the origin round trip completely.

HTML is the hardest thing to put on a CDN because it is the dynamic part. Full-page edge caching is the big win when the content allows it. Even without it, edge termination and a warm route to the origin cut the TTFB.

How does this affect the Core Web Vitals?

Main CDN correlates with the LCP. With Vercel, 90% of sites pass the LCP. With Cloudfront, 84% do.

Go fix it Configure Cloudflare for passing the Core Web Vitals → Time to First Byte → Free website cache warmer →
Related signals ETag present → Requests via CDN → HTTP protocol mix → HTTP protocol → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured