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New Google PageSpeed ​​Insights powered by Lighthouse 6 (beta): check your site’s performance

On March 16, Google Chrome released a beta version of Lighthouse 6. The final version will form the basis of measurements in the new PageSpeed ​​Insights and the Chrome browser developer console. Details and test engine inside.

Hello, Habr. I am Alexey from Loading.express.

At the last Chrome Developer Summit , they announced that they would release PageSpeed ​​Insights by January 2020.

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As soon as the notification came, we deployed the Lighthouse 6 beta release on our servers and studied in detail the innovations. Here are the main ones:

  • three new metrics - TBT, LCP and CLS;
  • updated device to open the site;
  • New audits for JS
  • New audits in the accessibility section
  • new audit item in the PWA section.

Check on the new Lighthouse engine here:
lh6.loading.express

Three new metrics in the new PageSpeed ​​report (lighthouse 6)


TBT - Total Blocking Time. This is the time to block input in milliseconds when a visitor cannot do anything on the site. It is loading. We wait. Even if you try to swipe, scroll, click - you will get the effect of freezing or movement with interruptions.

performance habr.com/ru/
TBT metrics for the Habr homepage

What is considered fast or slow:

  • 0–300 ms - green zone, fast;
  • 300-600 ms - orange zone, moderately;
  • more than 600 ms - red zone, slowly.

LCP - Largest Contentful Paint. Time to render the largest and most visible content on the screen. The moment when the site visitor realized that the site has loaded and you can start. This metric was developed in Google after research. We discussed it together with the Web Performance Working Group W3C , which included representatives of Airbnb Inc, Facebook, Mozilla Foundation, Intel Corporation and others.

What is good and bad:

  • 0-2 sec - green zone, fast;
  • 2-4 sec - orange zone, moderately;
  • more than 4 seconds - red zone, slowly.

CLS - Cumulative Layout Shift. This metric sums up the scores from each page shift that occurs during page loading. Everyone remembers the moment when he visits the page, you start reading and suddenly all the contents run away somewhere. This loaded the ads from above and pushed all the content down. Now Google considers these shifts and the more they are, the higher the score.

Values ​​from 0 to 1. Up to 0.5 is good, closer to 1 is bad.

The FID parameter was removed from the report. TBT and JS metering reports partially took over.

New device to open the site Moto G4



The imitation of the device on which Google opened your site was equal to the screen of the Nexus 5 from 2013. And many Performance consultants were perplexed until it was considered a model device. And so, in 2020 - a new device - Moto G4 (emulated) from 2016. And this means that on average around the world, people have updated the devices from which they access sites.

New audits in Lighthouse 6


JS - now, if too much javascript is executed when your site loads, then GPSI will report it separately.

Accessibility - new audit items relate to the display of site elements for text readers in audio format, for the visually impaired. There is an opinion that voice assistants will also use this markup. Character

Encoding Audit - Encoding must be declared.

PWA maskable icon audit - an audit that will check if there is a vector icon for a mask. If not, he will recommend making a vector format.

Conclusions about the new audit of the speed of loading sites Lighthouse 6


PageSpeed ​​Insights last had this global update in November 2018. Then many sites fell into the red zone, because prior to the update PageSpeed ​​did not measure the loading speed of sites, but showed recommendations for optimizing various parameters that could affect the loading speed.

Those who missed that update can still be mistaken and assure everyone that GPSI does not measure the speed of loading sites.

With the new Lighthouse 6, speed measurement will become more understandable for developers and website owners.

Fast sites and high conversions.

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