The State of Web Vitals

HTML document CDN on React sites

Direct from origin versus Cloudflare, Fastly, CloudFront, or Akamai: how serving the main HTML document through an edge CDN changes Time to First Byte (487 ms on Cloudflare vs 692 ms from origin) and Largest Contentful Paint.

Field data PhoneDesktopAll Scope All sites October 2026 edition · All devices field outcomes · React sites only
React Scoped to 9,570 sites out of 210,902 analyzed (frameworks) Compare with all sites →

47.1% of React sites have no an HTML edge CDN. Of the 52.9% that do, 69% use Fastly as, and 95% of those sites have a good LCP, against 85% of all React sites.

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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LCP pass rate

Sites with Fastly as an HTML edge CDN have a good LCP most often: 95%, against 85% of all React sites. Sites with Cloudflare as CDN have it least often, at 81%.

SitesGood, needs improvement, poor LCPMedian
All React sites9,11085%1.4s
Fastly 36.4%3,29895%1.2s
Netlify Edge 0.6%5988%2.2s
Amazon CloudFront 7.2%66183%1.5s
Cloudflare 7.5%68081%1.5s
Direct from origin (no CDN) 47.1%4,29978%1.6s
Vercel Edge 0.1%1377%2.0s
Akamai 1.0%10074%1.7s
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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An HTML edge CDN usage

52.9% of React sites use an HTML edge CDN, and two in three of those use Fastly as.

All React sites 9,570 sites
Direct from origin (no CDN) 47.1% An HTML edge CDN 52.9%
Sites with an HTML edge CDN 5,066 sites
Fastly 68.8% Cloudflare 14.2% Amazon CloudFront 13.6%
Fastly 68.8% Cloudflare 14.2% Amazon CloudFront 13.6% Akamai 2.0% Netlify Edge 1.2% Vercel Edge 0.3%
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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Where an HTML CDN saves time: TTFB and the four LCP phases

Across the four LCP sub-parts in Chrome's field data, the largest gap between Fastly as and no sits in time to first byte (TTFB): 410 ms median for Fastly as against 692 ms for no. Overall median field LCP is 1.2s for Fastly as (TTFB 410 ms, load delay 450 ms, load duration 136 ms, render delay 154 ms) versus 1.6s for no.

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP
All React sites 6,740516 ms439 ms439 mslab 439 ms1.4s
Netlify Edge 481074 ms894 ms106 mslab 106 ms2.2s
Akamai 82774 ms407 ms294 ms407 mslab 407 ms1.8s
Direct from origin (no CDN) 3,148692 ms420 ms420 mslab 420 ms1.6s
Fastly 2,453410 ms450 ms450 mslab 450 ms1.2s
Cloudflare 512487 ms469 ms469 mslab 469 ms1.5s
Amazon CloudFront 491509 ms471 ms471 mslab 471 ms1.5s
TTFB Resource load delay Resource load time Element render delay
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
4

An HTML edge CDN per platform

Wix sets the an HTML edge CDN to Fastly as on 58% of its sites, and 94% of Wix sites have a good LCP, against 85% of all sites.

PlatformAn HTML edge CDN on its sitesGood LCP
All React sites 9,570 sitesDirect from origin (no CDN) 47%Fastly 36%85%
Wix 5,824 sitesFastly 58%Direct from origin (no CDN) 27%94%
WordPress 2,342 sitesDirect from origin (no CDN) 82%61%
Direct from origin (no CDN) Fastly Cloudflare Amazon CloudFront Akamai Netlify Edge Vercel Edge
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTML edge CDN or the platform

Does the platform explain the an HTML edge CDN difference?

On Wix, 96% of sites with Fastly as an HTML edge CDN have a good LCP, against 92% of Wix sites without an HTML edge CDN. Within Wix, sites with Fastly as an HTML edge CDN have a good LCP more often.

Why putting the HTML document on an edge CDN cuts TTFB

Static assets like images and scripts are easy to put on a CDN, but the browser cannot discover any of them until the main HTML document arrives. Routing the main domain through an edge network terminates DNS, TCP, and TLS at a point of presence near the visitor, and full-page HTML caching at the edge removes the origin server round trip entirely. In Chrome's field data, serving HTML through Cloudflare cuts median TTFB to 487 ms and Fastly cuts it to 410 ms, compared with 692 ms for documents served directly from the origin.

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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Understanding HTML document CDN delivery

Serve the main HTML document through an edge CDN and cache anonymous page views at the edge wherever possible. Across the dataset, 47.1% of sites still serve HTML directly from an origin server (78% good LCP, 692 ms median TTFB), while sites on Cloudflare (81% good LCP, 487 ms TTFB) and Fastly (95% good LCP, 410 ms TTFB) start rendering significantly earlier. Even when HTML cannot be cached publicly, edge TLS termination, HTTP/3 support, and tiered origin routing cut connection latency on every navigation.

Go fix it Configure Cloudflare for passing the Core Web Vitals → Time to First Byte → Free website cache warmer →
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 9,110 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals ETag present → Requests via CDN → HTTP protocol mix → HTTP protocol → By Arjen Karel · 9,570 crawled React sites (9,110 with all devices Chrome field data, October 2026) · How we measured