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 (80% good LCP, 1.5s median) and 85.5% fire XMLHttpRequest calls (80% good LCP).
85.5% of React sites use XHR requests network resource type mix, and 80% of those sites have a good LCP, against 79% of all React sites.
LCP pass rate
Sites with XHR requests network resource type mix have a good LCP most often: 80%, against 79% of all React sites. Sites with stylesheet requests resource types have it least often, at 75%.
Network resource type mix usage
Script requests is the most used: 100.0% of React sites. XHR requests is 85.5% of React sites.
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): 667 ms median for XHR requests against 797 ms for stylesheet requests. Overall median field LCP is 1.5s for XHR requests (TTFB 667 ms, load delay 434 ms, load duration 152 ms, render delay 191 ms) versus 1.7s for stylesheet requests.
Network resource type mix per platform
Wix sets the network resource type mix to XHR requests on 100% of its sites, and 92% of Wix sites have a good LCP, against 79% of all sites. WordPress sets the network resource type mix to script requests on 100% of its sites, and 66% of WordPress sites have a good LCP.
Wix 5,824 sitesHTML document 100%Other resources (pings / beacons / manifests) 100%JavaScript files 100%Fetch API requests 100%Images 100%XMLHttpRequest (XHR) calls 100%Web fonts 100%CSS stylesheets 47%92%
WordPress 2,342 sitesJavaScript files 100%Images 100%HTML document 100%CSS stylesheets 99%Web fonts 98%Other resources (pings / beacons / manifests) 97%Fetch API requests 76%XMLHttpRequest (XHR) calls 59%66%Network resource types or the platform
Does the platform explain the network resource type mix difference?
On Wix, 92% of sites with XHR requests network resource type mix have a good LCP, against 92% of Wix sites with script requests. Within Wix, sites with XHR requests and script requests have a good LCP about equally often. On WordPress, 62% of sites with XHR requests network resource type mix have a good LCP, against 66% 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%, 79% good LCP at a 1.5s median). However, 91.4% of sites (8,749) also fire client-side fetch() requests during initial load (80% good LCP, 1.5s median) and 85.5% (8,182) fire XHR calls (80% good LCP, 1.5s median), often to fetch client-rendered content, A/B test configs, or cart state.
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 (79% good LCP) while 91.4% fire fetch() calls during load (80% good LCP).
By Arjen Karel · 9,570 crawled React sites (1,979 with desktop Chrome field data, October 2026). How we measured.