Real users first
We read the Chrome UX Report, Google’s public dataset of how real Chrome users experience your site. It’s the same data Google uses in rankings. We show the 75th-percentile value, the share of good, needs-improvement and poor visits, and the trend over the last 25 weeks, so you can see whether a fix actually worked.
Then the lab test
A Lighthouse run on Google’s servers simulates a page load on a mid-range phone and lists the biggest time savings: images to compress, render-blocking files, unused code.