PageSpeed Insights (PSI) is a tool designed to evaluate user experience on web pages across mobile and desktop devices, offering actionable suggestions for improvement. It utilizes both lab data, collected under controlled conditions ideal for troubleshooting, and field data from real users via the Chrome User Experience Report (CrUX), capturing metrics like First Contentful Paint (FCP), Largest Contentful Paint (LCP), and Cumulative Layout Shift (CLS). When sufficient data exists, PSI assesses page performance, categorizing it as good, needs improvement, or poor based on Web Vitals standards. PSI also integrates Lighthouse diagnostics for in-depth analyses on performance, accessibility, and SEO. By combining real-world user insights with simulated testing, PSI empowers developers to enhance website speed and overall experience effectively.