Lighthouse: Google's Free SEO Audit, Run on Our Own Site
Google's free, open-source site auditor. We ran it on 5 of our pages: accessibility 100, SEO 92. It found 2 real issues, including one line in robots.txt.
Lighthouse is a free Google tool that audits a page for performance, accessibility, best practices and SEO. pSkyro Labs ran it on 5 pages of its own site: accessibility 100, SEO 92, and two real issues found.
What it is
Lighthouse is Google's open-source auditor. Give it a URL and it scores the page out of 100 on performance, accessibility, best practices and SEO, with a list of what to fix.
See it in action
We ran Lighthouse 12.8 (mobile) on 5 pages of a local build of pskyrolabs.com.
Accessibility 100. Best practices 93. SEO 92.
An unknown line in robots.txt (−8 SEO points) and a logo image too small for sharp phone screens.
Finding 1: one line in robots.txt
Our robots.txt has a Content-Signal line that tells AI crawlers how they may use the content. Lighthouse doesn't recognise it yet and marks robots.txt as invalid. That one line costs 8 SEO points on every page.
Our call: the line is intentional and search engines ignore lines they don't understand. We're keeping it, and now we know why the score is 92.
Finding 2: a slightly soft logo
The logo file is 114×29 pixels, shown at 102×26. On a phone with a 1.5× screen it needs 153×39 to look sharp. A 2-minute fix: export it at 2×.
What we left out
Lighthouse also flagged console errors. They came from our test machine blocking analytics, not from the site, so they don't count. Performance isn't scored here because a local dev build isn't a fair speed test.
Why it matters
A dentist's site loses Google traffic after a redesign. Before paying for an audit, Lighthouse can show in two minutes whether the basics broke: missing meta descriptions, pages blocked from crawling, images too heavy for phones.
Try it yourself
What this means for your site
If a Lighthouse run shows weak titles, blocked pages or heavy images, the fix is usually in the build. That is the work behind website design and development at pSkyro Labs. To see what a site like yours should cost, use the website cost calculator. Next in the series: Pa11y, the free accessibility checker.
The verdict
The free SEO and speed audit every site should run before paying for one.
Run it monthly and after every redesign. Star it on GitHub.
FAQ
Is Lighthouse free?
Yes. Lighthouse is open source (Apache-2.0) and built into Chrome DevTools. You can also run it from the command line with Node.js.
What does Lighthouse check?
Performance, accessibility, best practices and SEO. Each gets a score out of 100, with a list of failed checks and how to fix them.
Is a Lighthouse SEO score of 100 enough to rank?
No. Lighthouse checks technical basics like titles, meta descriptions, crawlability and robots.txt. Rankings also depend on content, links and search intent.