Lighthouse Version 6 Changes: What’s New For Content Creators

woman on laptop at a restaurant

Version 6 of Lighthouse, Google’s open-source tool for improving the quality of web pages, will soon be here. If you don’t know what Lighthouse is, or why changes to it are important, we have one word for you:


Yes, Mediavine thinks about pagespeed so much that we turned two words into one to write it even faster. Jokes and poor spelling aside, the goal of faster pages and websites influences everything we do as a company.

Our Script Wrapper, which powers the ad technology for 6,800 websites, is lightweight and built for speed. So are Mediavine’s WordPress plugins; pagespeed concerns ultimately led to the creation of Trellis.

Moreover, we are constantly looking for ways to help our publishers maximize scores in Google’s PageSpeed Insights (PSI), and that means doing everything we can to give Mediavine products an advantage. 

As we spend our lives worrying about how our tools perform on PSI, when Google changes how it measures pagespeed, we take it very seriously. That change is coming in the form of the Lighthouse 6 update.

man's hands typing into Google on a laptop

What is Lighthouse?

You might not have used Lighthouse directly, but you’ve probably used PSI, which utilizes speed metrics powered by Lighthouse.

Lighthouse is actually a variety of tools that measure the time it takes to load a page, while providing a meaningful user experience.

When you visit PageSpeed Insights or use a Lighthouse Audit tool, Lighthouse uses a browser to measure a website as it loads.

That site is rendered using either your local version of Chrome or via a “headless” copy of Chrome that runs on a server, probably in California — if screen shots that include Mediavine’s CCPA are any indication.

Some of the metrics Lighthouse uses have names that aren’t the most self-explanatory or instructive, so here’s a little glossary:

  • First Contentful Paint: Yes, that is its real name. It marks the time at which the first text or image is loaded into view, and measures how long it takes a browser to render the first element on the page.
  • Speed Index: Measures how quickly the contents are visibly loaded, and the visual progression of the page load.
  • Largest Contentful Paint: Reports the render time of the largest content element in the viewport.
  • Time to Interactive: How long until a page is fully interactive, meaning it displays content and event handlers are in place for visible elements.
  • Total Blocking Time: Sum of time between your first contentful paint and time to interactive.
  • Cumulative Layout Shift: Measures how often a layout change happens as new content is loaded to the page.

What’s Changing in Version 6?

The metrics themselves, and the weight of those metrics, will change with the move from Version 5 to Version 6 of Lighthouse.

Specifically, Version 6 introduces Largest Contentful Paint, Total Blocking Time and Cumulative Layout Shift.

These new Lighthouse metrics mark a shift in prioritizing user experience concerns rather than speed for speed’s sake.

Users are often frustrated by Layout Shift, which occurs when elements are added to a web page unexpectedly. One example of this is lazy loaded images that aren’t properly spaced.

This experience is one of the reasons Mediavine integrated support for Jump to Recipe buttons into our Script Wrapper.

Tip: You can improve Largest Contentful Paint scores by avoiding adding large images to the first viewport of your site.

man's hands typing on a laptop

What Do Lighthouse Changes Mean For Me?

As we mentioned briefly above, PSI has been using Lighthouse 5 metrics for the last year or so but soon will start using Version 6.

It’s not clear exactly when the updated Lighthouse will be integrated with PSI; Google will make that transition when it’s ready.

According to the official Lighthouse Twitter, and other sources close to the product, we can expect it to be in effect by the end of May.

In any case, Lighthouse 6 will alter the way scores are calculated, while introducing new metrics for quantifying page performance.

As with any update, there will likely be minor changes in your pagespeed score, hopefully for the better. In any case, don’t panic.

The easiest and most effective way to improve pagespeed is to remove plugins that aren’t providing value for your site and users.

It’s also worth noting (shameless plug alert) that some of our initial Trellis test sites have seen an upward bump in their scores.

As always, stay tuned to our blog and social channels for more on Trellis, and email us with any pagespeed related questions.

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