PageSpeed Insights (PSI)

PageSpeed Insights is a free tool from Google that analyzes the performance of a single webpage and provides suggestions for improvement. A key feature of PSI is that it reports both Lab Data from a simulated Lighthouse test and Field Data from the CrUX (Chrome User Experience Report) for the given URL, if available. This provides a holistic view, showing both a reproducible diagnostic score and the actual performance experienced by real users over the last 28 days.