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.
Technical
Lighthouse
An open-source automated auditing tool in Chrome DevTools and PageSpeed Insights that runs lab tests for performance, accessibility, best practices and SEO.
In full
Lighthouse simulates a single page load under a fixed throttled environment and produces weighted category scores plus specific opportunities and diagnostics. Its performance score is lab data and does not determine Core Web Vitals assessment, which comes from CrUX field data. Its SEO audit is a shallow checklist — crawlability, titles, descriptions, viewport — and is no substitute for a real crawl.
Example
A Lighthouse run flags 640 KB of unused JavaScript and a missing `<meta name="viewport">` on a legacy template.
Related terms
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…
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.
Render-blocking resources
Stylesheets and synchronous scripts in the head that must be downloaded and processed before the browser can paint anything.
Viewport meta tag
The `<meta name="viewport">` declaration that tells mobile browsers how to size and scale a page to the device screen.
Where to read more
- Lighthouse Documentation · Tool Guide · developer.chrome.com
- PageSpeed Insights · Tool Guide · pagespeed.web.dev