The State of Web Vitals

Network resource types on React sites

Alongside HTML documents (100.0%), images (99.9%), scripts (100.0%), stylesheets (64.9%), and fonts (98.5%), 91.4% of audited sites (8,749) fire runtime fetch() requests (85% good LCP, 1.4s median) and 85.5% fire XMLHttpRequest calls (86% good LCP).

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

85.5% of React sites use XHR requests network resource type mix, and 86% of those sites have a good LCP, against 84% of all React sites.

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
1

LCP pass rate

Sites with XHR requests network resource type mix have a good LCP most often: 86%, against 84% of all React sites. Sites with stylesheet requests resource types have it least often, at 79%.

SitesGood, needs improvement, poor LCPMedian
All React sites5,48884%1.4s
XMLHttpRequest (XHR) calls 85.5%4,67686%1.3s
Fetch API requests 91.4%4,99685%1.4s
Other resources (pings / beacons / manifests) 98.6%5,39884%1.4s
Web fonts 98.5%5,41584%1.4s
Images 99.9%5,48284%1.4s
JavaScript files 100.0%5,48884%1.4s
HTML document 100.0%5,48884%1.4s
CSS stylesheets 64.9%3,76179%1.6s
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
2

Network resource type mix usage

Script requests is the most used: 100.0% of React sites. XHR requests is 85.5% of React sites.

Sites using each option (sites can use more than one) 9,570 sites
JavaScript files 100.0% HTML document 100.0% Images 99.9% Other resources (pings / beacons / manifests) 98.6% Web fonts 98.5% Fetch API requests 91.4% XMLHttpRequest (XHR) calls 85.5%
JavaScript files 100.0% HTML document 100.0% Images 99.9% Other resources (pings / beacons / manifests) 98.6% Web fonts 98.5% Fetch API requests 91.4% XMLHttpRequest (XHR) calls 85.5% CSS stylesheets 64.9%
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
3

LCP phase breakdown by network resource types loaded

Across the four LCP sub-parts in Chrome's field data, the largest gap between XHR requests and stylesheet requests sits in time to first byte (TTFB): 471 ms median for XHR requests against 595 ms for stylesheet requests. Overall median field LCP is 1.3s for XHR requests (TTFB 471 ms, load delay 437 ms, load duration 127 ms, render delay 173 ms) versus 1.6s for stylesheet requests.

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP
All React sites 4,169502 ms433 ms180 ms433 mslab 439 ms1.4s
HTML document 4,169502 ms433 ms180 ms433 mslab 439 ms1.4s
JavaScript files 4,169502 ms433 ms180 ms433 mslab 439 ms1.4s
Web fonts 4,124502 ms433 ms180 ms433 mslab 439 ms1.4s
Images 4,168502 ms433 ms180 ms433 mslab 439 ms1.4s
Fetch API requests 3,830484 ms433 ms176 ms433 mslab 440 ms1.4s
Other resources (pings / beacons / manifests) 4,106499 ms434 ms179 ms434 mslab 441 ms1.4s
XMLHttpRequest (XHR) calls 3,615471 ms437 ms173 ms437 mslab 445 ms1.3s
CSS stylesheets 2,874595 ms441 ms198 ms441 mslab 445 ms1.6s
TTFB Resource load delay Resource load time Element render delay
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
4

Network resource type mix per platform

Wix sets the network resource type mix to XHR requests on 100% of its sites, and 94% of Wix sites have a good LCP, against 84% of all sites. WordPress sets the network resource type mix to HTML documents on 100% of its sites, and 63% of WordPress sites have a good LCP.

PlatformNetwork resource type mix on its sitesGood LCP
All React sites 9,570 sitesJavaScript files 100%HTML document 100%Images 100%Other resources (pings / beacons / manifests) 99%Web fonts 99%Fetch API requests 91%XMLHttpRequest (XHR) calls 85%CSS stylesheets 65%84%
Wix 5,824 sitesOther resources (pings / beacons / manifests) 100%HTML document 100%JavaScript files 100%Fetch API requests 100%Images 100%XMLHttpRequest (XHR) calls 100%Web fonts 100%CSS stylesheets 47%94%
WordPress 2,342 sitesHTML document 100%JavaScript files 100%Images 100%CSS stylesheets 99%Web fonts 98%Other resources (pings / beacons / manifests) 97%Fetch API requests 76%XMLHttpRequest (XHR) calls 59%63%
JavaScript files HTML document Images Other resources (pings / beacons / manifests) Web fonts Fetch API requests XMLHttpRequest (XHR) calls CSS stylesheets
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
5

Network resource types or the platform

Does the platform explain the network resource type mix difference?

On Wix, 94% of sites with XHR requests network resource type mix have a good LCP, against 94% of Wix sites with script requests. Within Wix, sites with XHR requests and script requests have a good LCP about equally often. On WordPress, 60% of sites with XHR requests network resource type mix have a good LCP, against 63% of WordPress sites with script requests. Within WordPress, sites with XHR requests and script requests have a good LCP about equally often.

How early fetch() and XHR API calls compete with critical rendering assets

Almost every web page loads an HTML document (100.0%), images (99.9%), scripts (100.0%), stylesheets (64.9%), and web fonts (98.5%, 84% good LCP at a 1.4s median). However, 91.4% of sites (8,749) also fire client-side fetch() requests during initial load (85% good LCP, 1.4s median) and 85.5% (8,182) fire XHR calls (86% good LCP, 1.3s median), often to fetch client-rendered content, A/B test configs, or cart state.

The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
6

Understanding network resource types

Render above-the-fold data server-side in the initial HTML document rather than waiting on client-side fetch() or XMLHttpRequest calls during startup, and defer telemetry beacons until after LCP. Across all audited sites, 99.9% load images (84% good LCP) while 91.4% fire fetch() calls during load (85% good LCP).

Go fix it Optimize images for Core Web Vitals → 14 methods to defer JavaScript → Remove unused CSS →
The State of Web Vitals · October 2026 · React: 9,570 crawled sites · 5,488 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals Cookies per site → Media per page → Responsive image markup → font-display strategy → By Arjen Karel · 9,570 crawled React sites (5,488 with phone Chrome field data, October 2026) · How we measured