Name: Shopify first-party vs third-party stylesheets and the Core Web Vitals (October 2026) - The State of Web Vitals
Creator: Arjen Karel

99.9% of Shopify sites use first-party stylesheets stylesheet origin (first-party vs third-party), and 95% of those sites have a good LCP, against 95% of all Shopify sites.

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

1

LCP pass rate

Sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP most often: 95%, against 95% of all Shopify sites. Sites with third-party stylesheets CSS origin have it least often, at 94%.

SitesGood, needs improvement, poor LCPMedian

All Shopify sites5,82595%1.4s

First-party stylesheets 99.9%5,81995%1.4s

Third-party stylesheets 78.1%4,67494%1.4s

GoodNeeds improvementPoorSites: with Chrome field data

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

2

Stylesheet origin (first-party vs third-party) usage

First-party stylesheets is the most used: 99.9% of Shopify sites.

Sites using each option (sites can use more than one) 8,243 sites

First-party stylesheets 99.9% Third-party stylesheets 78.1%

First-party stylesheets 99.9% Third-party stylesheets 78.1%

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

3

LCP phase breakdown for first-party and third-party stylesheets

Across the four LCP sub-parts in Chrome's field data, the largest gap between first-party stylesheets and third-party stylesheets sits in resource load delay: 590 ms median for first-party stylesheets against 613 ms for third-party stylesheets. Overall median field LCP is 1.4s for first-party stylesheets (TTFB 402 ms, load delay 590 ms, load duration 206 ms, render delay 312 ms) versus 1.4s for third-party stylesheets.

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP

Shopify sites with stylesheet origin (first-party vs third-party) 5,046402 ms590 ms206 ms312 ms590 mslab 596 ms1.4s

First-party stylesheets 5,043402 ms590 ms206 ms312 ms590 mslab 596 ms1.4s

Third-party stylesheets 4,086409 ms613 ms205 ms330 ms613 mslab 618 ms1.4s

TTFB Resource load delay Resource load time Element render delay

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

4

Stylesheet origin (first-party vs third-party) per framework

Vue sets the stylesheet origin (first-party vs third-party) to first-party stylesheets on 100% of its sites, and 94% of Vue sites have a good LCP, against 95% of all sites.

FrameworkStylesheet origin (first-party vs third-party) on its sitesGood LCP

Shopify sites with stylesheet origin (first-party vs third-party) 8,243 sitesFirst-party stylesheets 100%Third-party stylesheets 78%95%

Vue 933 sitesFirst-party stylesheets 100%Third-party stylesheets 94%94%

jQuery 3,150 sitesFirst-party stylesheets 100%Third-party stylesheets 87%93%

First-party stylesheets Third-party stylesheets

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

5

Stylesheet origin or the framework

Does the framework explain the stylesheet origin (first-party vs third-party) difference?

On jQuery, 93% of sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP, against 92% of jQuery sites with third-party stylesheets. Within jQuery, sites with first-party stylesheets and third-party stylesheets have a good LCP about equally often. On Vue, 94% of sites with first-party stylesheets stylesheet origin (first-party vs third-party) have a good LCP, against 94% of Vue sites with third-party stylesheets. Within Vue, sites with first-party stylesheets and third-party stylesheets have a good LCP about equally often.

How cross-origin CSS files add DNS and TLS round-trips to the critical rendering path

Because external stylesheets block rendering by default, fetching a CSS file from a third-party domain (such as fonts.googleapis.com, cdnjs, or a widget CDN) stalls first paint behind a fresh DNS lookup, TCP handshake, and TLS negotiation. Across 8,237 sites (99.9%) with first-party CSS, good LCP is 95% (1.4s median), whereas across 6,434 sites (78.1%) with third-party CSS, good LCP drops to 94% (1.4s median).

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv

6

Understanding first-party vs third-party stylesheets

Copy external font and icon stylesheets (Google Fonts, Font Awesome, Bootstrap CDN) into your own build pipeline or origin server so every render-blocking CSS file shares the primary HTTP/2 or HTTP/3 connection. Across all audited sites, 99.9% use first-party CSS (95% good LCP) and 78.1% load third-party CSS (94% good LCP).

Go fix it Self-host Google Fonts → Eliminate render-blocking resources →

The State of Web Vitals · October 2026 · Shopify: 8,246 crawled sites · 5,825 with phone field data · 8,243 sites with stylesheet origin (first-party vs third-party)By Arjen Karel · corewebvitals.io/state-of-cwv