Google Lighthouse

Updated on Jan 22, 2025

What is Google Lighthouse?

Google Lighthouse is a free, open-source tool that helps improve the quality of web pages.
It audits web pages for performance, accessibility, SEO, and more.

Why use Google Lighthouse?

Improve search engine ranking.
Lighthouse can help you optimize your pages for better search engine ranking results.
Improve user experience
Lighthouse can help you improve your website's speed, performance, and overall user experience (UX).
Improve website quality
Lighthouse can help you identify areas for improvement and take concrete steps to optimize your website.

What does Google Lighthouse do?

Analyzes page load speed, accessibility, search engine optimization (SEO), and more
Provides performance scores and suggestions for faster loading
Focuses on Google's Core Web Vitals, which are the essential metrics Google uses to measure web pages' speed and overall UX
Evaluates essential features like service worker registration and offline functionalities
You can run Lighthouse in Chrome DevTools, From the command line, and As a Node module

How to Get Started and Go to The Page You Want to Test

Right-click on the page you want to audit
From the drop-down menu select "Inspect"

Right-click drop-down menu with "inspect" boxed.

You will want to select "Lighthouse." You may need to select the double arrows in the top bar to find "Lighthouse."

Inspect menu with the right double arrow button selected and the "Lighthouse" button boxed.

Select what you would like to test.
Once you have them selected, select "Generate Report."
It would be a best practice to select only "accessibility" and "best practices" and then run both the "mobile" and "desktop" device. For this purpose, we suggest running it twice.

Lighthouse homepage with some options selected from the menu and the "Generate report" button boxed.

Once completed, it will give a percentage score out of 100.
You can go through the testing site to find more information about what did not pass the automatic checker.

Note: You may see a warning at the top telling you that issues affect this lighthouse run, even if you use an incognito window. This is ok, but please be aware of possible false positives.

How to understand the results of Test

The Issues Are Grouped by Type

Issues that failed the automated checks will appear.
You can expand the accordion by selecting the "Carat (^) Symbol" on the right to see more details, including the failing elements.

What about Items you may need to check with Lighthouse Manually

Lighthouse will provide you with a list of items to check manually. I am finding it lower on the results page.

Information on how to test them if you expand the carat on the right.

Manually testing and how to tab order dropdown opened.

What are Passed Audits

This section is for your reference about items that have passed! You do not have to do anything with this information.
The information could be used to update roadmaps and others on progress.