Without a public announcement, Google has chosen to release a major update of Page Speed Insights. V5 of page speed insights now uses Lighthouse as its analysis engine and also incorporates field data provided by the Chrome User Experience Report (CrUX). v5 of the API will now provide CrUX data and all of the Lighthouse audits. Previous versions of the PSI API will be deprecated in six months.
Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, and more.
You can run Lighthouse in Chrome DevTools, from the command line, or as a Node module. You give Lighthouse a URL to audit, it runs a series of audits against the page, and then it generates a report on how well the page did. From there, use the failing audits as indicators on how to improve the page. Each audit has a reference doc explaining why the audit is important, as well as how to fix it.
We have seen some significant changes in the new v5 of page speed insights. These include:
- Field Data: This uses the Chrome User Experience report and shows you the First Contentful Paint (FCP) and the First Input Delay (FID).
- Lab Data: Analysis the current page on an emulated mobile network to show you FCP, FMP, speed index, first CPU idle, time to interactive and the estimated input latency.
- Diagnostics: This gives you a report on the performance of your application.