February 19, 2020

Google Lighthouse: What can Google Lighthouse do?

It’s no secret that loading times are one of the most important SEO factors, and Google also prefers fast websites. Google wants to offer users a good user experience, and that also includes the speed of a website. This is where Google Lighthouse comes in. The tool from Google promises a technically more successful website through analyzes and specific suggestions for improvement in various areas. 

Google Lighthouse carries out these audits

Five areas can be tested with Google Lighthouse: performance, best practices, SEO, accessibility, and progressive web apps. Depending on your needs, certain sections can be switched on and off. Each area is marked with a score that summarizes the results. 

light house

Performance – How fast does your website load?

In my opinion, performance is the most effective and most important area. Google Lighthouse shows here in detail how long it takes until the individual elements of the website are loaded, and users can actually use the content. The following six categories are analyzed:

  1. First Contentful Paint: The time until the first visual reaction is recognizable for the user.
  2. First Meaningful Paint: The time until the main part of the page is loaded.
  3. Speed ​​Index: Indicates the time at which the content elements of the page are displayed visibly.
  4. Time to Interactive: The time until the user has to wait to interact with the page.
  5. First CPU Idle: Indicates the time until the CPU is relieved to process user input.
  6. Estimated Input Latency: The time it takes the website to respond to user input.

In the Opportunities area, Lighthouse shows suggestions for improvement and the associated time savings potential. You will also find further detailed information and tips on the respective improvement suggestions here.

google light house

Accessibility – Is the website accessible? The accessibility of your website

The Accessibility Audit checks whether the website has been optimized for people with disabilities. In the area of ​​accessibility, various tests are carried out, which either pass or fail. Examples include the use of alt attributes, screen readers, or the right color contrast. The tests are prioritized according to importance, from which the results are then used to calculate an average. 

Best Practices – What standards a modern website should have

Best practices also either pass or fail. Above all, the security aspects of the website are analyzed. This includes, for example, the use of HTTPS or HTTP / 2. 

SEO – Is Your Site Search Engine Friendly?

Here Google Lighthouse checks how good the crawl ability of a website is. The tests in the SEO area are very basic. This part currently consists of 13 tests and contains points that should normally not be missing on any website. For this reason, the values ​​here are very good for all websites in most cases. If this is not the case, you should quickly work through the points, since they belong to the SEO basics. 

Progressive web apps

Progressive web apps, or PWAs for short, are dynamically generated websites that behave like apps and, for example, adapt quickly to your smartphone. Here Lighthouse examines, among other things, whether the website works without an internet connection or whether the website reports a service worker. 

How do I activate Google Lighthouse?

There are several ways to use Google Lighthouse. To do this, you should first install the latest version of Google Chrome. The first option is via the so-called DevTools. Google Lighthouse can be found there under “Audits.” Another option to access the tool is via the Chrome plugin. Google Lighthouse can also be used from the command line. 


With Lighthouse, Google offers a very useful tool that can be used by both beginners and advanced users. Great potential can sometimes be uncovered, particularly in the area of ​​performance. Google Lighthouse is also ideal for getting a quick overview of the technical aspects of a page. However, it should be noted that Google Lighthouse is not a pure PageSpeed ​​tool. That means the performance score has nothing to do with the loading speed. It is only calculated from certain implemented measures that have been recommended. In other words, a performance score of 95 sounds nice, but it doesn’t have to mean that your site is super fast. Even when implementing certain measures, you should first be careful and question the optimization. Not all suggestions make sense, and most of them are often associated with a lot of effort. 

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