Tag Archives: speed

PageSpeed Insights, now powered by Lighthouse

At Google, we know that speed matters and we provide a variety of tools to help everyone understand the performance of a page or site. Historically, these tools have used different analysis engines. Unfortunately, this caused some confusion because the recommendations from each tool were different. Today, we're happy to announce that Pagespeed Insights (PSI) now uses Lighthouse as its analysis engine. This allows developers to get the same performance audits and recommendations everywhere: on the web, from the command line, and in Chrome DevTools. PSI also incorporates field data provided by the Chrome User Experience Report (CrUX). Version 5 of the PageSpeed Insights API will now provide CrUX data and all of the Lighthouse audits. Previous versions of the PSI API will be deprecated in six months.
Pagespeed Insights is now powered by Lighthouse

PageSpeed Insights provides the following information:
  • Lab Data. 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.
  • Field Data. 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 data set 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.
  • Opportunities. 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.
  • Diagnostics. This section provides additional information about how a page adheres to best practices for web development.
The PSI v5 API now returns this new analysis together with CrUX data, and all Lighthouse category data (Performance, Progressive Web App, Accessibility, Best Practices, and SEO) for a given URL.
We have more information about the changes in our FAQ. If you have any questions, please use Stack Overflow and tag your question with the pagespeed-insights tag.

Posted by Rui Chen and Paul Irish, PageSpeed Insights and Lighthouse teams

Using page speed in mobile search ranking

People want to be able to find answers to their questions as fast as possible — studies show that people really care about the speed of a page. Although speed has been used in ranking for some time, that signal was focused on desktop searches. Today we’re announcing that starting in July 2018, page speed will be a ranking factor for mobile searches.

The “Speed Update,” as we’re calling it, will only affect pages that deliver the slowest experience to users and will only affect a small percentage of queries. It applies the same standard to all pages, regardless of the technology used to build the page. The intent of the search query is still a very strong signal, so a slow page may still rank highly if it has great, relevant content.

We encourage developers to think broadly how about performance affects a user’s experience of their page and to consider a variety of user experience metrics. Although there is no tool that directly indicates whether a page is affected by this new ranking factor, here are some resources that can be used to evaluate a page’s performance.

  • Chrome User Experience Report, a public dataset of key user experience metrics for popular destinations on the web, as experienced by Chrome users under real-world conditions
  • Lighthouse, an automated tool and a part of Chrome Developer Tools for auditing the quality (performance, accessibility, and more) of web pages
  • PageSpeed Insights, a tool that indicates how well a page performs on the Chrome UX Report and suggests performance optimizations

As always, if you have any questions or feedback, please visit our webmaster forums.

Real-world data in PageSpeed Insights

PageSpeed Insights provides information about how well a page adheres to a set of best practices. In the past, these recommendations were presented without the context of how fast the page performed in the real world, which made it hard to understand when it was appropriate to apply these optimizations. Today, we’re announcing that PageSpeed Insights will use data from the Chrome User Experience Report to make better recommendations for developers and the optimization score has been tuned to be more aligned with the real-world data.

The PSI report now has several different elements:

  • The Speed score categorizes a page as being Fast, Average, or Slow. This is determined by looking at the median value of two metrics: First Contentful Paint (FCP) and DOM Content Loaded (DCL). If both metrics are in the top one-third of their category, the page is considered fast.
  • The Optimization score categorizes a page as being Good, Medium, or Low by estimating its performance headroom. The calculation assumes that a developer wants to keep the same appearance and functionality of the page.
  • The Page Load Distributions section presents how this page’s FCP and DCL events are distributed in the data set. These events are categorized as Fast (top third), Average (middle third), and Slow (bottom third) by comparing to all events in the Chrome User Experience Report.
  • The Page Stats section describes the round trips required to load the page’s render-blocking resources, the total bytes used by the page, and how it compares to the median number of round trips and bytes used in the dataset. It can indicate if the page might be faster if the developer modifies the appearance and functionality of the page.
  • Optimization Suggestions is a list of best practices that could be applied to this page. If the page is fast, these suggestions are hidden by default, as the page is already in the top third of all pages in the data set.

For more details on these changes, see About PageSpeed Insights. As always, if you have any questions or feedback, please visit our forums and please remember to include the URL that is being evaluated.