Core Web Vitals
Core Web Vitals are Google page-experience metrics — Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift — measured on real devices.
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What Core Web Vitals measure
Core Web Vitals are Google’s page-experience metrics, reported from real devices: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability. Field data is collected over a 28-day window, and the thresholds are published by Google.
What they do and do not control
The metrics describe how a page behaves under real conditions. They are not a score of the site, they do not sum into one number a customer can compare, and they are not a ranking switch. A page can pass all three and still be a bad page; a fast page with no answer on it does not become useful.
What moves them
LCP is usually the hero image or a render-blocking resource: compress the image, preload the one that matters, and stop loading fonts nobody sees above the fold. INP follows JavaScript: ship less of it and defer what remains. CLS follows layout: reserve space for images, embeds and anything that appears late.
Where it fits in the product
The SEO work reads field data where it exists and lab evidence where it does not, and labels which one is being shown. A performance fix is a change set with a preview and a measured window, so an improvement is reported with the context that produced it rather than as a headline number.
Related terms
- Canonical URL
A canonical URL is the address a page declares as its true location with rel=canonical. It consolidates duplicates and must match the sitemap and hreflang.
- GEO (generative engine optimization)
Generative engine optimization makes a site easy for an AI answer engine to retrieve, verify and cite: clear answers, entity facts, schema and bot access.
- Change set
A change set is one proposed website change, written in a sandbox, previewed, run through the gates, approved or rejected, then deployed and measured.
Not sure where the term fits? Run a free audit of the site you already have and read the findings before deciding what to change.
All terms