At a glance the headline numbers for CDN performance
Performance breakdown by cdn.
Cloudflare passes CLS most often of any CDN. 79.8% of its sites pass. CloudFront passes least at 71.7%. No CDN (origin) (the most-used CDN) sits at 77.6%. The gap is 8 percentage points.
The ranking sorted by CLS at p75, fastest first
| # | CDN | CLS p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | Vercel | 0.08 | 80.3% | 981 | |
| 2 | Netlify | 0.08 | 78.4% | 343 | |
| 3 | Akamai | 0.08 | 79.7% | 4,958 | |
| 4 | Cloudflare | 0.08 | 79.8% | 23,815 | |
| 5 | Fastly | 0.09 | 78.6% | 6,447 | |
| 6 | No CDN (origin) | 0.09 | 77.6% | 142,788 | |
| 7 | CloudFront | 0.12 | 71.7% | 6,145 |
Passing CLS per CDN which group passes the CLS most often
80% of Vercel sites pass CLS. CloudFront trails 8 points behind, leaving 28% of its sites failing. computed
All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75
One row per CDN, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.
Akamai leads on CLS: 80% of its sites pass. CloudFront trails at 72%. computed
Why this matters for the Core Web Vitals, and where to start fixing it
A CDN sits between your server and your visitors, serving content from a location near each of them instead of from a single origin. That shortens the trip every request makes, which shows up first in Time to First Byte and then in how quickly the main content can paint. A good CDN also handles caching, compression and modern protocols, so the gains reach well beyond raw distance.
Start by making sure the CDN is actually caching your pages and assets rather than passing everything through to the origin. Turn on compression and HTTP/2 or HTTP/3, set sensible cache headers, and check that your largest image is served from the edge. A CDN that passes every request through to the origin gives you almost none of this.
How does your CDN affect Core Web Vitals?
Among the most-used CDNs, Vercel reaches a good CLS on 80.3% of sites; CloudFront on 71.7%.
Chrome field data from 189,915 sites, representing millions of real page loads. How we measured.