WordPress subresource network protocols (HTTP/2, HTTP/3) and the Core Web Vitals
HTTP/2 (96.9%), HTTP/3 QUIC (78.1%), and legacy HTTP/1.1 (62.1%) across all page subrequests: how connection protocols move Largest Contentful Paint.
96.9% of WordPress sites use HTTP/2 subresource network protocols, and 70% of those sites have a good LCP, against 70% of all WordPress sites.
LCP pass rate
Sites with HTTP/2 subresource network protocols have a good LCP most often: 70%, against 70% of all WordPress sites. Sites with HTTP/1.1 network protocols have it least often, at 67%.
Subresource network protocols usage
HTTP/2 is the most used: 96.9% of WordPress sites.
How subresource network protocols affect the four LCP phases
Across the four LCP sub-parts in Chrome's field data, the largest gap between HTTP/2 and HTTP/1.1 sits in time to first byte (TTFB): 1132 ms median for HTTP/2 against 1170 ms for HTTP/1.1. Overall median field LCP is 1.9s for HTTP/2 (TTFB 1132 ms, load delay 341 ms, load duration 166 ms, render delay 236 ms) versus 2.0s for HTTP/1.1.
Subresource network protocols per framework
Alpine sets the subresource network protocols to HTTP/2 on 99% of its sites, and 80% of Alpine sites have a good LCP, against 70% of all sites.
Subresource network protocols or the framework
Does the framework explain the subresource network protocols difference?
Almost every site with HTTP/2 subresource network protocols is a jQuery site, and almost every jQuery site has HTTP/2 subresource network protocols, so the data can't tell HTTP/2 subresource network protocols and jQuery apart. On Vue, 68% of sites with HTTP/2 subresource network protocols have a good LCP, against 65% of Vue sites with HTTP/3. Within Vue, sites with HTTP/2 and HTTP/3 have a good LCP about equally often. On React, 60% of sites with HTTP/2 subresource network protocols have a good LCP, against 58% of React sites with HTTP/3. Within React, sites with HTTP/2 and HTTP/3 have a good LCP about equally often.
Why most pages mix HTTP/2, HTTP/3, and HTTP/1.1 in a single load
While a page's HTML document uses a single connection, its subresources come from first-party CDNs, font hosts, and third-party scripts. Across 189,798 sites, 96.9% load subresources over HTTP/2 (70% good LCP), 78.1% negotiate HTTP/3 on at least one origin (69% good LCP), and 62.1% still make at least one legacy HTTP/1.1 request (67% good LCP).
Understanding subresource network protocols
Serve all first-party static assets over HTTP/2 and HTTP/3 via a modern CDN, and audit third-party scripts or unproxied asset hosts that still fall back to HTTP/1.1 (62.1% of sites). HTTP/1.1 origins cannot multiplex concurrent requests over a single connection, adding head-of-line blocking when multiple assets share that domain.
By Arjen Karel · 63,295 crawled WordPress sites (60,855 with all devices Chrome field data, October 2026). How we measured.