PSI reports how fast a page feels and behaves, summarised through Core Web Vitals — Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. It combines a lab test (Lighthouse, run on demand) with field data from real Chrome users where available, and lists concrete opportunities to improve.
Speed is a genuine ranking and UX factor, but it is one input among many. I use PSI to find real problems — heavy images, render-blocking scripts, layout shift — not to chase a perfect 100. A fast, stable page also helps AI and crawlers process content reliably.
FAQ
Frequently asked questions
Google's set of user-experience metrics — loading (LCP), interactivity (INP) and visual stability (CLS) — that PageSpeed Insights measures and reports.
Not necessarily. Fix the real issues PSI flags and target good Core Web Vitals in field data; a perfect lab score is rarely worth chasing for its own sake.