At a glance the headline numbers for CMS
The CMS the site is built on, as a per-site dimension.
WordPress powers 73.3% of the sites we measured.
CMS who uses what, and how stable each group is
Little daylight between the groups: every variant sits near 0.00 median CLS. computed
Passing CLS per CMS which group passes the CLS most often
98% of Wix sites pass CLS. Adobe commerce trails 18 points behind. computed
Why this matters for the Core Web Vitals, and where to start fixing it
The CMS decides your defaults: the theme's markup, the plugin economy, how images are sized, what loads in the head. Most sites never change those defaults, so the platform's choices become the platform's vitals.
No platform is doomed and none is safe. The spread inside a platform is bigger than the gap between platforms: a tuned site on a slow-median CMS beats a neglected site on a fast one. The platform pages rank them on real field data.
How does this affect the Core Web Vitals?
CMS correlates with the CLS. With Wix, 98% of sites pass the CLS. With Adobe commerce, 80% do. The causal link is weak: the choice mostly marks what kind of site made it.
The split is bigger on LCP. With Shopify, 95% of sites pass it. With WordPress, 70% do.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.