Google Updates PageSpeed Insights With Lighthouse 13.6.0
PageSpeed Insights now uses Lighthouse 13.6.0, changing how page load times are simulated, according to Search Engine Journal. This update may result in higher scores for some websites.
Original reporting · searchenginejournal.com
Original: “Google Lighthouse Update Changes How PageSpeed Insights Simulates Loading via @sejournal, @MattGSouthern”
Read “Google Lighthouse Update Changes How PageSpeed Insights Simulates Loading via…” at Search Engine Journal →
How this was written. CTCV wrote this article with a language model from Search Engine Journal’s reporting (model: @cf/meta/llama-3.3-70b-instruct-fp8-fast); it describes that reporting rather than adding to it. The original, linked above, is the full story.
Key points from Search Engine Journal’s report
- PageSpeed Insights now uses Lighthouse 13.6.0, which changes how page load times are simulated.
- The update may result in higher scores for some websites, particularly those heavily dependent on JavaScript.
- The Lighthouse team has updated the Agentic Resource Discovery (ARD) audit to check for the new ard.json manifest name.
Google has updated PageSpeed Insights to use Lighthouse 13.6.0, which was released on October 27, Search Engine Journal reported. This version of Lighthouse changes how it simulates page load times, which may result in different PageSpeed Insights scores for some websites.
The updated version of Lighthouse improves the simulated First Contentful Paint (FCP) and Largest Contentful Paint (LCP), making them more accurate and generally resulting in higher scores, according to Chrome’s Web Performance Developer Advocate, Barry Pollard.
Websites heavily dependent on JavaScript are more likely to be impacted by the updated test, Pollard said. He also noted that single-page apps (SPAs) have seen improvements in their results since the Lighthouse update.
The experimental soft navigation metrics in Chrome are a separate way of measuring user experience, using data from real Chrome users through the Chrome User Experience Report (CrUX), while Lighthouse uses a simulated test.
The release notes for Lighthouse 13.6.0 list several changes to Lantern, the simulation behind the estimates, aimed at improving its accuracy. For example, Lantern now uses Chrome’s own render-blocking label for each request, instead of relying on fetch priority.
The Lighthouse team has also updated the Agentic Resource Discovery (ARD) audit, which now checks for an ARD manifest under the new name ard.json, in addition to the old ai-catalog names.
The performance score in PageSpeed Insights is based on data generated by Lighthouse, and the update may result in higher lab scores for some websites. However, it is essential to compare the field data, which represents real visits to the website, to get an accurate picture of the website’s performance.
Questions and answers
What is the impact of the Lighthouse 13.6.0 update on PageSpeed Insights scores?
The update may result in different PageSpeed Insights scores for some websites, particularly those heavily dependent on JavaScript.
How does Lighthouse 13.6.0 simulate page load times?
Lighthouse 13.6.0 uses a simulated test, while the experimental soft navigation metrics in Chrome use data from real Chrome users through the Chrome User Experience Report (CrUX).
What is the Agentic Resource Discovery (ARD) audit in Lighthouse?
The ARD audit checks for an ARD manifest under the new name ard.json, in addition to the old ai-catalog names, to improve the accuracy of the simulation.
