WordPress speculation rules posture (prefetch vs prerender) and the Core Web Vitals

Sites with prerender speculation rules pass all three Core Web Vitals most often: 63%, against 60% of all WordPress sites. The biggest gap is LCP, 78% against 76%.

Sites with prerender speculation rules have a good LCP most often: 78%, against 76% of all WordPress sites. Sites with prefetch speculation rules have it least often, at 75%.

Sites with prefetch speculation rules have a good INP most often: 100%, against 100% of all WordPress sites. Sites with prerender speculation rules have it least often, at 99%.

Sites with prerender speculation rules have a good CLS most often: 79%, against 78% of all WordPress sites. Sites with prefetch speculation rules have it least often, at 78%.

85.1% of WordPress sites use speculation rules, and 99% of those use prefetch. Prerender is 1% of the sites with speculation rules, 0.6% of all WordPress sites.

On jQuery, 85% of sites use prefetch speculation rules, and 60% of jQuery sites pass all three Core Web Vitals, against 60% of all sites. On Vue, 93% of sites use prefetch, and 57% of Vue sites pass all three.

On jQuery, 85% of sites use prefetch speculation rules, and 75% of jQuery sites have a good LCP, against 76% of all sites. On Vue, 93% of sites use prefetch, and 75% of Vue sites have a good LCP.

On jQuery, 85% of sites use prefetch speculation rules, and 100% of jQuery sites have a good INP, against 100% of all sites. On Vue, 93% of sites use prefetch, and 99% of Vue sites have a good INP.

On jQuery, 85% of sites use prefetch speculation rules, and 77% of jQuery sites have a good CLS, against 78% of all sites. On Vue, 93% of sites use prefetch, and 75% of Vue sites have a good CLS.

FrameworkSpeculation rules on its sitesPass all three

WordPress sites with speculation rules 63,293 sitesPrefetch 84%No rules 15%60%

Alpine 380 sitesPrefetch 88%No rules 11%69%

jQuery 60,312 sitesPrefetch 85%No rules 14%60%

Vue 4,844 sitesPrefetch 93%57%

React 2,233 sitesPrefetch 89%50%

Prefetch No rules Prerender

Does the framework explain the speculation rules difference?

On jQuery, 60% of sites with prefetch speculation rules pass all three Core Web Vitals, against 61% of jQuery sites without speculation rules. Within jQuery, sites with and without speculation rules pass all three about equally often.

On jQuery, 75% of sites with prefetch speculation rules have a good LCP, against 79% of jQuery sites without speculation rules. Within jQuery, sites with prefetch speculation rules have a good LCP less often.

On jQuery, 100% of sites with prefetch speculation rules have a good INP, against 99% of jQuery sites without speculation rules. Within jQuery, sites with and without speculation rules have a good INP about equally often.

On jQuery, 77% of sites with prefetch speculation rules have a good CLS, against 75% of jQuery sites without speculation rules. Within jQuery, sites with and without speculation rules have a good CLS about equally often.

How prefetch, prerender-until-script, and prerender differ in Chrome

A prefetch rule only downloads the next page's HTML document ahead of the click, removing network TTFB on the subsequent navigation while leaving subresources and rendering until after the visitor navigates. A prerender-until-script rule downloads the HTML and subresources and builds the DOM and CSSOM in a hidden renderer, pausing before JavaScript executes. A full prerender rule executes scripts and paints the next page in the background so activation is near-instant.