Webmasters: test websites with Google's Lighthouse for Chrome

Martin Brinkmann
Aug 16, 2018
Development, Google Chrome, Google Chrome extensions

Lighthouse is a free open source browser extension by Google designed to audit web pages and to reveal areas the site could be improved in. The functionality is also integrated into the Chrome browser.

Today's webmasters have numerous tools at their disposal that assist them but the Web has changed significantly as well. It is no longer sufficient to install WordPress and a SEO plugin, and be done with the technical side of things.

Nowadays it is necessary to take lots of things into account, from using HTTPS and making sure the site is responsive to improving site performance.

Lighthouse for Chrome

lighthouse for chrome

Lighthouse for Chrome audits web pages that you run the extension on. It simulates mobile access to the page and audits the page in the categories performance, progressive web app, accessibility, best practices, and SEO.

You can disable audit categories before you run tests and may disable the simulated throttling of the processor as well.

The scan of the page takes less than a minute to complete and a score of each category is displayed at the top afterward.

The score scale ranges from 0 (very bad) to 100 (excellent) and give you a quick overview of areas where the page shines and where it does not.

Each category provides a wealth of data. Lighthouse uses a color scheme to indicate bad (red), average (brown), and good (green) areas which helps a lot.

Issues that require attention are highlighted with a red exclamation mark. You can expand any item to find out more about the recommendation.

The extension revealed to me that two robots.txt entries had syntax errors (missing ":") and I corrected the issue immediately to resolve the error.

The performance listing is special as it lists opportunities and diagnostics. Opportunities provide estimates on time saves when certain practices are implemented. For instance, removing unused stylesheet rules would reduce the size of the style file and improve loading time because of that.

SEO is also worth checking out as it checks for crawling and indexing issues, whether the site is mobile friendly, and whether best practices, e.g. title elements and meta descriptions, or the use of rel=canonical, are implemented properly on the site.

Developer Tools version

desktop audit site performance seo

Lighthouse is also integrated into the Chrome Developer Tools. Tap on F12, select Audits and run the audit on the desktop or mobile version of the site.

The core difference between the two implementations is that the Lighthouse extension gets new features first. You can audit sites simulating desktop connections only in the Developer Tools, however and if that is what you want to do, need to use the built-in option to do that.

If you check the desktop version, you may want to disable the Progressive Web App audit category to speed things up and focus on the more important areas unless the site makes use of PWA.

Closing Words

Lighthouse is a useful tool for webmasters to audit websites and discover opportunities to improve the performance, search engine visibility or accessibility in the process.

Lighthouse checks some very important basics, e.g. use of canonical, that every site should get right; this alone is reason enough to give your site a good audit using it if only for making sure that you have the basics right.

Most webmasters may not need the Chrome extensions as the functionality is baked into Chrome as well. The Chrome extension does get new features and improvements first though so it may pay off to keep an eye on development.

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  1. iampriteshdesai said on March 26, 2009 at 3:15 pm

    Well, some time ago some guy (me) used to copy some of your articles with backlinks, but you said no.

  2. techandlife said on March 26, 2009 at 4:06 pm

    I came across an interesting blog post where they mentioned using Tracer to insert a script on your blog. If any part of your page is copied, it adds a link back to your site to the copied content.
    Here’s the link:


  3. Kaushik said on March 26, 2009 at 4:20 pm

    If you publish full feeds, which you do, you should include a link to the original article or link to the homepage at the bottom of each article. This can usually be done with plugins or simple hacks.

    This way everytime a spam blog republishes your feed, you automatically get an inbound link.

    You should do that.

  4. Daniel Pataki said on March 26, 2009 at 7:10 pm

    I personally hate it if people copy my content and I ask them to remove it every time. The reason is, that if they copy most of my article and link back, the article is still a copy and this does not bode well for me in search engines.

    Apart from that, I just get irked by it, it’s my article, not yours :)

    Kaushik, that’s a great tip, thanks!

  5. iampriteshdesai said on March 26, 2009 at 7:12 pm

    Well, I have read that google picks out the seeds from the fruit.
    If there is a link pointing back to the original article, google attributes the article to the place where the link points.
    Also your PR goes up dues to the links.

  6. Alfonzo Carco said on May 19, 2011 at 11:47 am

    Greetings! I’ve been reading your website for a long time now and finally got the bravery to go ahead and give you a shout out from Dallas Tx! Just wanted to say keep up the fantastic job!

  7. Mansoor said on August 27, 2011 at 10:26 pm

    I have a web portal designed to help students find educational content as they go online. My idea is to let them utilize their time effectively rather than just monkeying around on social networking sites. For the same, I need resources that I possibly can’t generate on my own. Resources like subject matter for example, for English I need grammar rules, summary writing rules etc. Now if I find some useful stuff on a website and I wish to copy it on my own providing the link of the source with it, will that be legal?

  8. Mel said on February 1, 2012 at 5:06 am

    If you’re going to copy content, always make sure to have at least a 3:1 ratio of commentary. For example, for every 3 paragraphs that you cite, make sure you have at least a paragraph of commentary for it. This tends to result in favorable SEO.

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