Shopify subresource network protocols and the Core Web Vitals
HTTP/2 (99.6%), HTTP/3 QUIC (99.9%), and legacy HTTP/1.1 (99.9%) across all page subrequests: how connection protocols move Largest Contentful Paint.
99.9% of Shopify sites use HTTP/3 subresource network protocols, and 96% of those sites have a good LCP, against 96% of all Shopify sites.
LCP pass rate
Sites with HTTP/3 subresource network protocols have a good LCP most often: 96%, against 96% of all Shopify sites. Sites with HTTP/2 network protocols have it least often, at 96%.
Subresource network protocols usage
HTTP/3 is the most used: 99.9% of Shopify 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/3 and HTTP/2 sits in element render delay: 298 ms median for HTTP/3 against 299 ms for HTTP/2. Overall median field LCP is 1.3s for HTTP/3 (TTFB 389 ms, load delay 589 ms, load duration 208 ms, render delay 298 ms) versus 1.3s for HTTP/2.
Subresource network protocols per framework
jQuery sets the subresource network protocols to HTTP/3 on 100% of its sites, and 94% of jQuery sites have a good LCP, against 96% of all sites. Vue sets the subresource network protocols to HTTP/1.1 on 100% of its sites, and 95% of Vue sites have a good LCP.
Subresource network protocols or the framework
Does the framework explain the subresource network protocols difference?
On jQuery, 94% of sites with HTTP/3 subresource network protocols have a good LCP, against 94% of jQuery sites with HTTP/1.1. Within jQuery, sites with HTTP/3 and HTTP/1.1 have a good LCP about equally often. On Vue, 95% of sites with HTTP/3 subresource network protocols have a good LCP, against 95% of Vue sites with HTTP/1.1. Within Vue, sites with HTTP/3 and HTTP/1.1 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, 99.6% load subresources over HTTP/2 (96% good LCP), 99.9% negotiate HTTP/3 on at least one origin (96% good LCP), and 99.9% still make at least one legacy HTTP/1.1 request (96% 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 (99.9% 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 · 8,246 crawled Shopify sites (8,062 with all devices Chrome field data, October 2026). How we measured.