Wix speculation rules and the Core Web Vitals
Conservative, moderate, eager or immediate: which speculation rules sites use, and whether those sites pass LCP, INP and CLS more often.
0.8% of Wix sites have no speculation rules. Of the 99.2% that do, 99% use eager, and 89% of those sites pass all three Core Web Vitals, against 89% of all Wix sites.
0.8% of Wix sites have no speculation rules. Of the 99.2% that do, 99% use eager, and 95% of those sites have a good LCP, against 94% of all Wix sites.
0.8% of Wix sites have no speculation rules. Of the 99.2% that do, 99% use eager, and 96% of those sites have a good INP, against 96% of all Wix sites.
0.8% of Wix sites have no speculation rules. Of the 99.2% that do, 99% use eager, and 98% of those sites have a good CLS, against 97% of all Wix sites.
Core Web Vitals pass rate
Sites with eager speculation rules pass all three Core Web Vitals most often: 89%, against 89% of all Wix sites. The biggest gap is LCP, 95% against 94%.
Sites with eager speculation rules have a good LCP most often: 95%, against 94% of all Wix sites.
Sites with eager speculation rules have a good INP most often: 96%, against 96% of all Wix sites.
Sites with eager speculation rules have a good CLS most often: 98%, against 97% of all Wix sites.
Speculation rules usage
99.2% of Wix sites use speculation rules, and 99% of those use eager.
Speculation rules per framework
React sets the speculation rules to eager on 99% of its sites, and 89% of React sites pass all three Core Web Vitals, against 89% of all sites.
React sets the speculation rules to eager on 99% of its sites, and 94% of React sites have a good LCP, against 94% of all sites.
React sets the speculation rules to eager on 99% of its sites, and 96% of React sites have a good INP, against 96% of all sites.
React sets the speculation rules to eager on 99% of its sites, and 97% of React sites have a good CLS, against 97% of all sites.
React 5,620 sitesEager 99%89%94%96%97%Speculation rules or the framework
Does the framework explain the speculation rules difference?
Almost every site with eager speculation rules is a React site, and almost every React site has eager speculation rules, so the data can't tell eager speculation rules and React apart.
Almost every site with eager speculation rules is a React site, and almost every React site has eager speculation rules, so the data can't tell eager speculation rules and React apart.
Almost every site with eager speculation rules is a React site, and almost every React site has eager speculation rules, so the data can't tell eager speculation rules and React apart.
Almost every site with eager speculation rules is a React site, and almost every React site has eager speculation rules, so the data can't tell eager speculation rules and React apart.
How much speculation rules speed up the next page
Speculation rules only speed up the page a visitor opens next, not the page they land on, and Chrome's field data counts both. A prefetch fetches the next page's HTML early, which takes time off its TTFB and its LCP. A prerender also builds the next page before the click, so it can open with an LCP close to zero and its layout shifts happen out of sight. In Shopify's test, moderate cut the median LCP of the next page by 228 ms on desktop compared with conservative, and by 24 ms on phones.
Understanding speculation rules eagerness
Use eager. Sites with eager speculation rules pass all three Core Web Vitals most often, and the theory fits: the earlier Chrome starts, the more of the next page is ready when the visitor clicks. Almost all of those sites are Wix sites, so part of that lead is the platform. The cost is pages loaded that nobody opens, so check that your server can take the extra requests. Conservative waits until the visitor presses a link. Moderate starts after a 200 ms hover on desktop, and on a phone half a second after scrolling stops near a link. Eager starts after a 10 ms hover on desktop, and on a phone once a link has been on screen for 50 ms. Immediate starts as soon as Chrome reads the rule. On WordPress, core uses conservative, which made no visible difference in this data; the wp_speculation_rules_configuration filter switches it to eager.
By Arjen Karel · 5,621 crawled Wix sites (3,077 with phone Chrome field data, October 2026). How we measured.