WordPress first-party vs third-party scripts and the Core Web Vitals

Sites with third-party scripts script origin (first-party vs third-party) have a good INP most often: 100%, against 100% of all WordPress sites. Sites with first-party scripts script origin have it least often, at 100%.

Sites with first-party scripts script origin (first-party vs third-party) have a good LCP most often: 76%, against 76% of all WordPress sites. Sites with third-party scripts script origin have it least often, at 75%.

First-party scripts is the most used: 100.0% of WordPress sites. Third-party scripts is 77.6% of WordPress sites.

Alpine sets the script origin (first-party vs third-party) to third-party scripts on 94% of its sites, and 99% of Alpine sites have a good INP, against 100% of all sites. jQuery sets the script origin (first-party vs third-party) to first-party scripts on 100% of its sites, and 100% of jQuery sites have a good INP.

Alpine sets the script origin (first-party vs third-party) to third-party scripts on 94% of its sites, and 82% of Alpine sites have a good LCP, against 76% of all sites. jQuery sets the script origin (first-party vs third-party) to first-party scripts on 100% of its sites, and 75% of jQuery sites have a good LCP.

FrameworkScript origin (first-party vs third-party) on its sitesGood INP

WordPress sites with script origin (first-party vs third-party) 63,280 sitesFirst-party scripts 100%Third-party scripts 78%100%

jQuery 60,311 sitesFirst-party scripts 100%Third-party scripts 79%100%

React 2,233 sitesFirst-party scripts 100%Third-party scripts 84%100%

Vue 4,844 sitesFirst-party scripts 100%Third-party scripts 64%99%

Alpine 380 sitesFirst-party scripts 100%Third-party scripts 94%99%

First-party scripts Third-party scripts

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

On jQuery, 100% of sites with third-party scripts script origin (first-party vs third-party) have a good INP, against 100% of jQuery sites with first-party scripts. Within jQuery, sites with third-party scripts and first-party scripts have a good INP about equally often. On Vue, 99% of sites with third-party scripts script origin (first-party vs third-party) have a good INP, against 99% of Vue sites with first-party scripts. Within Vue, sites with third-party scripts and first-party scripts have a good INP about equally often.

Almost every site with first-party scripts script origin (first-party vs third-party) is a jQuery site, and almost every jQuery site has first-party scripts script origin (first-party vs third-party), so the data can't tell first-party scripts script origin (first-party vs third-party) and jQuery apart. On Vue, 75% of sites with first-party scripts script origin (first-party vs third-party) have a good LCP, against 73% of Vue sites with third-party scripts. Within Vue, sites with first-party scripts and third-party scripts have a good LCP about equally often. On React, 66% of sites with first-party scripts script origin (first-party vs third-party) have a good LCP, against 65% of React sites with third-party scripts. Within React, sites with first-party scripts and third-party scripts have a good LCP about equally often.

How external third-party scripts compete with first-party interactivity

First-party scripts execute on 100.0% of audited sites (63,280, 100% good INP at a 48ms median). Four out of five sites (77.6%, 49,131) also load third-party scripts from external domains (100% good INP, 49ms median), adding unscheduled timer callbacks, event listeners, and long tasks to the shared browser main thread.