SEO glossary · Updated
Lighthouse SEO score: what it checks, and what it doesn't
Lighthouse is Google's open-source page auditing tool. Its SEO category runs a short list of basic checks and gives a 0 to 100 score.
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Lighthouse is an open-source tool from Google that audits a web page. It runs in Chrome DevTools, from the command line, as a Node module, and inside PageSpeed Insights, and it scores four categories: Performance, Accessibility, Best Practices and SEO.
What the SEO category checks
- The page has a meta description.
- Links have descriptive text.
- hreflang is valid.
- rel=canonical is valid.
- The page returns a successful HTTP status code.
- robots.txt is valid, and the page isn't blocked from indexing.
- The page doesn't use plugins, and tap targets are sized for mobile.
- A manual reminder to check structured data.
Each automated SEO audit is weighted equally in the score; the structured data check is manual and doesn't count.
What a 100 doesn't tell you
A perfect Lighthouse SEO score means the page passes these basics. It doesn't mean the page will rank. Lighthouse runs in a browser, so it doesn't check how crawlers that don't run JavaScript see the page, whether AI crawlers are allowed in robots.txt or blocked by a firewall, whether snippet controls keep you out of AI Overviews, or anything about your content's quality, links or competition.
| Lighthouse SEO | Also check |
|---|---|
| Meta description present | Title tag, H1 and heading outline |
| Page not blocked from indexing | Canonical target, soft 404s, Search Console indexing status |
| robots.txt valid | Which crawlers it actually allows, including AI search bots |
| Runs JavaScript like a browser | Content in the raw HTML for crawlers that don't |
Check it on your own site
What the free audit tests for this
- Raw HTML visibility
- robots.txt rules
- Edge access
- Snippet controls
One URL, about 20 seconds, no login. You get the result of every check and the exact fix for the top three issues.
Audit your website freeFAQ
Does a Lighthouse SEO score of 100 mean good SEO?+
It means the page passes Lighthouse's basic SEO checks. Rankings depend on much more, including content, relevance, links and how crawlers see the page.
Is Lighthouse the same as PageSpeed Insights?+
PageSpeed Insights runs Lighthouse for its lab data and adds field data from real Chrome users.
Sources
- Lighthouse overview — Chrome for Developers
- Lighthouse SEO audits: meta description — Chrome for Developers