First-party vs third-party scripts and the Core Web Vitals
99.7% of audited sites (196,481) execute first-party scripts (99% good INP, 49ms median), while 79.3% (156,198) also execute third-party scripts from external origins (99% good INP, 50ms median).
79.3% of sites use third-party scripts script origin (first-party vs third-party), and 99% of those sites have a good INP, against 99% of all sites.
99.7% of sites use first-party scripts script origin (first-party vs third-party), and 86% of those sites have a good LCP, against 86% of all sites.
Core Web Vitals pass rate
Sites with third-party scripts script origin (first-party vs third-party) have a good INP most often: 99%, against 99% of all sites. Sites with first-party scripts script origin have it least often, at 99%.
Sites with first-party scripts script origin (first-party vs third-party) have a good LCP most often: 86%, against 86% of all sites. Sites with third-party scripts script origin have it least often, at 86%.
Script origin (first-party vs third-party) usage
First-party scripts is the most used: 99.7% of sites. Third-party scripts is 79.3% of sites.
Understanding first-party vs third-party scripts
How external third-party scripts compete with first-party interactivity
First-party scripts execute on 99.7% of audited sites (196,481, 99% good INP at a 49ms median). Four out of five sites (79.3%, 156,198) also load third-party scripts from external domains (99% good INP, 50ms median), adding unscheduled timer callbacks, event listeners, and long tasks to the shared browser main thread.
Audit external <script> origins regularly, remove unused marketing tags, and move analytics collection to server-side endpoints or Web Workers so third-party scripts do not block user interactions. Across all audited sites, 99.7% run first-party scripts (49ms median INP) and 79.3% run third-party scripts (50ms median INP).
How script origin (first-party vs third-party) plays out per platform
What the field data shows when you isolate a single CMS or framework.
WordPress 65,494 sites 77.6% of WordPress sites execute third-party scripts (100% good INP vs 100% on first-party).
Across 65,494 WordPress sites, 100.0% execute first-party scripts (100% good INP, 48ms median) and 77.6% also load cross-origin third-party scripts (100% good INP, 49ms median).
Shopify 8,570 stores 100.0% of Shopify stores execute both first-party and cross-origin scripts (99% good INP).
Across 8,570 Shopify storefronts, 100.0% load scripts from the primary domain and 100.0% load cross-origin scripts (99% good INP, 61ms median).
React & Next.js 9,570 sites 94.7% of React & Next.js sites load cross-origin scripts (99% good INP, 49ms median).
Across 9,570 React sites, 100.0% run first-party bundles (99% good INP) and 94.7% also execute cross-origin scripts (99% good INP, 49ms median).
By Arjen Karel · 210,902 crawled sites (69,745 with desktop Chrome field data, 196,999 sites with script origin (first-party vs third-party), October 2026). How we measured.