Google last week announced the integration of Lighthouse as Pagespeed Insights’ analysis engine. Google says this enables developers to get the same performance audits and recommendations on the web.
Pagespeed Insights (PSI) also incorporates field data provided by the Chrome User Experience Report (CrUX).
According to Google, the new version 5 of the PSI API now also provides CrUX data and all of the Lighthouse audits. Previous versions of the PSI API will be deprecated in six months.
Information available in Pagespeed Insights (PSI)
PSI fetches and analyzes the page using Lighthouse, which simulates how a mobile device loads a page. It computes a set of performance metrics for the page (such as First Contentful Paint and Time to Interactive) and summarizes these metrics with a performance score from 0-100. Scores are categorized into three levels; 90 and up is considered to be a good score.
PSI also displays real-world performance metrics (First Contentful Paint and First Input Delay) for the page and its origin. (As a result, we’ve also deprecated the origin: query in PSI). Note that not all sites may have field data available for display. The dataset relies on a version of the Chrome User Experience Report that is updated daily and is aggregated over the previous 28 days. Keep in mind that the metrics here may be different from the ones in the Lab Data section as they capture a wide spectrum of real-world network conditions and devices used by Chrome users.
PSI provides suggestions on how to improve the page’s performance metrics. Each suggestion in this section estimates how much faster the page will load if the improvement is implemented.
This section provides additional information about how a page adheres to best practices for web development.