Before we get into anything, we would like to answer this question first: what is Google Lighthouse? Lighthouse is a free, automated tool journey by Google that audits the user experience on webpages. Just Like the building for which it was named, it can cast light on the areas of a site that require improvement.
Google Lighthouse is a tool you’ll use to ascertain where your site is creating a negative experience for users and Google. For the sake of accounting for common real-world conditions, Lighthouse simulates loading your page with an unsteady 3G connection.
When you run your site URL through Lighthouse, it’ll return feedback on a spread of various site features which will need improvement. For instance, if your page takes too long to load or isn’t mobile-friendly enough, Lighthouse will show you that.
Google Lighthouse can measure a spread of metrics on your website to make a comprehensive picture of the general user experience. Here’s a breakdown of the most things Lighthouse will measure on your website.
Google Lighthouse Performance metrics:
Google Lighthouse measures two primary sorts of metrics — performance metrics and SEO metrics. Performance metrics mainly relate to the method of loading the page and include the following:
Cumulative layout shift (CLS): CLS measures what percentage times the page layout shifts during loading (making page elements jump around to different locations).
First contentful paint (FCP): FCP measures how long it takes for a page to load the primary piece of the document object model (DOM) content.
Largest contentful paint (LCP): LCP measures how long it takes for a page to load its most significant element. If a page is usually made from the text and includes a video, the video will likely be the element LCP measures.
Speed index: Speed index is a measure of how long it takes for the visual elements of a page to display (as in, how quickly you’ll view them, not how fast you’ll interact with them).
Time to Interactive (TTI): TTI is measure how long it takes for users to be ready to click on and interact with the weather on a page.
Total blocking time (TBT): TBT measures how long it takes for the page to load from start to end completely. More specifically, it measures the length of your time between the FCP and, therefore, the TTI.
Each of those metrics gives Google an image of your site’s loading experience. For instance, if your TTI runs too long, it means you’ll have users clicking on content without it responding, which is understandably frustrating and creates a bad user experience.
Whereas performance metrics check out issues associated with the direct loading experience, SEO metrics specialize in things that impact Google rankings and site traffic. Here are a number of the most ones:
Valid robots.txt: Your txt file — which tells Google’s crawling algorithms which links on a site it can index — should be correctly formatted so Google can read it.
Image alt tags: Images should have alt tags whenever possible, which give an outline of the image and provides Google with how to factor it into search rankings.
Mobile-friendliness: Google ranks pages supported their mobile format, so your site should be mobile-friendly if you want it to seem in search results.
Title and meta description: Pages on your site should have an optimized title tag and meta description for Google to display in search results.
Unwanted plugins: Lighthouse will check for any unwanted plugins like Java or Flash that would negatively impact the user experience.
By optimizing these metrics, you’ll give yourself a foothold in Google search results, reaching more users and outperforming the competition.
How to use Google Lighthouse
If you’re wondering how you’ll use Google Lighthouse, you’re in luck — it’s an easy and straightforward process. To start, identify what page you would like to audit and use Chrome as your browser of choice. Once you’re ready, watch this video.