Core Web Vitals

What Core Web Vitals means

Two of the three describe rendering and interaction, which no AI crawler performs.

Where Core Web Vitals comes up on this site

• Core Web Vitals without CrUX: field data for small sitesThree sources of Core Web Vitals and what each can tell a small site .t{font:600 13px system-ui,sans-serif;fill:var(--ink)}.s{font:12px…
• Screaming Frog vs Sitebulb vs CrawlCheck: AI crawler auditsCore Web Vitals do not apply to crawlers at all: a crawler does not paint, scroll or click, and it does not count toward Chrome field data.
• Agent readiness checkers: Is It Agent Ready? vs CrawlCheckIts page-level sections describe the home page, and its Core Web Vitals come from Google’s public field data, so they are absent when Google has no sample for the site.
• Lighthouse scores vary between runs: two runs, 225% apartField data, from real visitors at the 75th percentile, is the measurement Core Web Vitals are judged on, but Chrome only publishes it for sites with enough visits.
• Why caching only successes kept our scans slowIf your own site is one of the many with no Chrome UX Report data, here is how to measure Core Web Vitals without it .

Definitions that name Core Web Vitals

LCP · CLS · INP

Related terms in Delivery and rendering

What arrives on the wire, and what only exists after something else runs.

broken embed · payload ratio · render dependence · render dependence gap · edge cache pinning · TTFB · CrUX · field data · prompt injection · Hydration mismatch · Dynamic rendering · DOM depth · Edge transformation · 202 interstitial · rate limiting · bot management platform

Questions about Core Web Vitals

What is Core Web Vitals?

Google's field measurements of loading, interactivity and layout stability, drawn from real Chrome users.

Which area of the glossary does Core Web Vitals belong to?

Delivery and rendering: What arrives on the wire, and what only exists after something else runs.

← TTFB  ·  CrUX →

See it in the full glossary · 772 terms across 19 areas.