Core Web Vitals
Google's set of three field-measured user experience metrics — LCP, INP and CLS — used as part of the page experience signals in ranking.
TechnicalCrUXField data
Chrome User Experience Report
Google's public dataset of real-user performance measurements from opted-in Chrome users, and the official source of Core Web Vitals assessment.
In full
CrUX aggregates a rolling 28-day window of metrics per origin and, where traffic is sufficient, per URL, exposed through BigQuery, an API, the CrUX dashboard, PageSpeed Insights and Search Console. Because it requires a popularity threshold, low-traffic URLs fall back to origin-level data or have none at all. The 28-day window means fixes take weeks to show up fully, which is why lab tools are used for iteration.
Example
After a performance release, PageSpeed Insights still shows red field data for three weeks while the CrUX window rolls forward.
Related terms
PageSpeed Insights
Google's public tool that shows CrUX field data and a Lighthouse lab audit for a URL and its origin, side by side.
Lighthouse
An open-source automated auditing tool in Chrome DevTools and PageSpeed Insights that runs lab tests for performance, accessibility, best…
Interaction to Next Paint
A Core Web Vital measuring overall responsiveness as the latency of the worst (approximately) interaction on a page; good is 200 ms or…
Largest Contentful Paint
A Core Web Vital measuring the render time of the largest image, video poster or text block visible in the viewport; good is 2.5 s or less…