About PageSpeed Insights

PageSpeed Insights analyzes the content of a web page, then generates suggestions to make that page faster.

The PageSpeed Insights API (PSI) reports on the performance of a page on both mobile and desktop devices, and provides suggestions on how that page may be improved.

PSI provides both lab and field data about a page. Lab data is useful for debugging performance issues, as it is collected in a controlled environment. However, it may not capture real-world bottlenecks. Field data is useful for capturing true, real-world user experience - but has a more limited set of metrics.