PageSpeed

The PageSpeed tab includes data from PageSpeed Insights which uses Lighthouse for speed auditing, and is able to look up real-world data from the Chrome User Experience Report (CrUX).

To pull in PageSpeed data simply go to ‘Configuration > API Access > PageSpeed Insights’, insert a free PageSpeed API key, connect and run a crawl. Data will then start to be populated against crawled URLs.

Please read our PageSpeed Insights integration guide on how to set up a free API and configure the SEO Spider.

The following speed metrics, opportunities and diagnostics data can be configured to be collected via the PageSpeed Insights API integration.

Overview Metrics

  • Total Size Savings
  • Total Time Savings
  • Total Requests
  • Total Page Size
  • HTML Size
  • HTML Count
  • Image Size
  • Image Count
  • CSS Size
  • CSS Count
  • JavaScript Size
  • JavaScript Count
  • Font Size
  • Font Count
  • Media Size
  • Media Count
  • Other Size
  • Other Count
  • Third Party Size
  • Third Party Count

CrUX Metrics

  • CrUX Performance
  • CrUX First Contentful Paint Time (sec)
  • CrUX First Contentful Paint Category
  • CrUX First Input Delay Time (sec)
  • CrUX First Input Delay Category
  • CrUX Origin Performance
  • CrUX Origin First Contentful Paint Time (sec)
  • CrUX Origin First Contentful Paint Category
  • CrUX Origin First Input Delay Time (sec)
  • CrUX Origin First Input Delay Category

Lighthouse Metrics

  • Performance Score
  • Time to First Byte (ms)
  • First Contentful Paint Time (sec)
  • Speed Index Time (sec)
  • Time to Interactive (sec)
  • First Contentful Paint Score
  • First Meaningful Paint Time (sec)
  • First Meaningful Paint Score
  • Speed Index Score
  • Estimated Input Latency (ms)
  • Estimated Input Latency Score
  • First CPU Idle (sec)
  • First CPU Idle Score
  • Time to Interactive Score

Opportunities

  • Eliminate Render-Blocking Resources Savings (ms)
  • Defer Offscreen Images Savings (ms)
  • Defer Offscreen Images Savings
  • Efficiently Encode Images Savings (ms)
  • Efficiently Encode Images Savings
  • Properly Size Images Savings (ms)
  • Properly Size Images Savings
  • Minify CSS Savings (ms)
  • Minify CSS Savings
  • Minify JavaScript Savings (ms)
  • Minify JavaScript Savings
  • Remove Unused CSS Savings (ms)
  • Remove Unused CSS Savings
  • Serve Images in Next-Gen Formats Savings (ms)
  • Serve Images in Next-Gen Formats Savings
  • Enable Text Compression Savings (ms)
  • Enable Text Compression Savings
  • Preconnect to Required Origin Savings
  • Server Response Times (TTFB) (ms)
  • Server Response Times (TTFB) Category
  • Multiple Redirects Savings (ms)
  • Preload Key Requests Savings (ms)
  • Use Video Format for Animated Images Savings (ms)
  • Use Video Format for Animated Images Savings
  • Total Image Optimization Savings (ms)

Diagnostics

  • DOM Element Count
  • JavaScript Execution Time (sec)
  • JavaScript Execution Time Category
  • Efficient Cache Policy Savings
  • Minimize Main-Thread Work (sec)
  • Minimize Main-Thread Work Category
  • Text Remains Visible During Webfont Load

You can read more about the definition of each metric, opportunity or diagnostic according to Lighthouse.

Filters

  • Eliminate Render-Blocking Resources – This highlights all pages with resources that are blocking the first paint of the page, along with the potential savings.
  • Properly Size Images – This highlights all pages with images that are not properly sized, along with the potential savings when they are resized appropriately.
  • Defer Offscreen Images – This highlights all pages with images that are hidden or offscreen, along with the potential savings if they were lazy-loaded.
  • Minify CSS – This highlights all pages with unminified CSS files, along with the potential savings when they are correctly minified.
  • Minify JavaScript – This highlights all pages with unminified JavaScript files, along with the potential savings when they are correctly minified.
  • Remove Unused CSS – This highlights all pages with unused CSS, along with the potential savings when they are removed of unnecessary bytes.
  • Efficiently Encode Images – This highlights all pages with unoptimised images, along with the potential savings.
  • Serve Images in Next-Gen Formats – This highlights all pages with images that are in older image formats, along with the potential savings.
  • Enable Text Compression – This highlights all pages with text based resources that are not compressed, along with the potential savings.
  • Preconnect to Required Origin – This highlights all pages with key requests that aren’t yet prioritizing fetch requests with link rel=preconnect, along with the potential savings.
  • Reduce Server Response Times (TTFB) – This highlights all pages where the browser has had to wait for over 600ms for the server to respond to the main document request.
  • Avoid Multiple Redirects – This highlights all pages which have resources that redirect, and the potential saving by using the direct URL.
  • Preload Key Requests – This highlights all pages with resources that are third level of requests in your critical request chain as preload candidates.
  • Use Video Format for Animated Images – This highlights all pages with animated GIFs, along with the potential savings of converting them into videos.
  • Avoid Excessive DOM Size – This highlights all pages with a large DOM size over the recommended 1,500 total nodes.
  • Reduce JavaScript Execution Time – This highlights all pages with average or slow JavaScript execution time.
  • Serve Static Assets With An Efficient Cache Policy – This highlights all pages with resources that are not cached, along with the potential savings.
  • Minimize Main-Thread Work – This highlights all pages with average or slow execution timing on the main thread.
  • Ensure Text Remains Visible During Webfont Load – This highlights all pages with fonts that may flash or become invisible during page load.

Please read the Lighthouse performance audits guide for more definitions and explanations of each of the opportunities and diagnostics above.

The speed opportunities, source pages and resource URLs that have potential savings can be exported in bulk via the ‘Reports > PageSpeed’ menu.

PageSpeed reporting

PageSpeed Insights API Status & Errors

The PSI Status column shows whether an API request for a URL has been a ‘success’ and shows data, or there has been an error and no data is displayed. An ‘error’ usually reflects the web interface, where you would see the same error and message.

The ‘PSI Error’ column displays the full message received from the PSI API to provide more information about the cause. Some errors are due to the Lighthouse audit itself failing, other errors can be due to the PSI API being unavailable when the request is made.

Please read our FAQ on PageSpeed Insights API Errors for more information.