Google’s PageSpeed Insights (PSI) measures the performance of a webpage on mobile and desktop devices, and then provide various suggestions to improve that page. It provides many type of data after scanning for developers:
- Speed Score: It tells you how good your webpage is optimized as per all Google’s indicators and what is the overall score of your webpage according to Google’s score metrics.
- Lab datais collected in a controlled environment, that is with a set of predefined devices and network settings. It is effective for debugging performance issues, and its testing can be easily reproduced.
- Field data(also called Real User Monitoring or RUM) includes performance data coming from real page loads. It’s effective to capture true, real-world user experience, but the set of metrics is limited as well as its debugging potential.
- Opportunities includes recommendations about performance metrics that could improve page loading time. Each recommendation includes an estimation of the load time the page could save if the suggestions were implemented.
- Passed Audits This tells you how much your website is already optimized from performance prospective and doesn’t require further optimization or developer’s intervention.