What is Lighthouse?
Also called: Lighthouse score
The short answer
Lighthouse is Google's open-source auditing tool that scores a page from 0 to 100 on performance, accessibility, best practices and SEO, with specific fixes.
What people say: “green scores”, “100 on Lighthouse”.
Lighthouse, explained
It runs a simulated lab test, so scores vary between runs and devices. Treat it as a diagnostic list of fixes; real-user Core Web Vitals are the outcome that counts.
Scores of 90 and above show green.
Questions people ask about Lighthouse
What is Lighthouse?
Lighthouse is Google's open-source auditing tool that scores a page from 0 to 100 on performance, accessibility, best practices and SEO, with specific fixes.
Is a 100 Lighthouse score necessary?
No; green scores and passing real-user Core Web Vitals matter more than the last few points.
Related terms
PageSpeed Insights is Google's free tool that shows a page's real-user Core Web Vitals, where available, alongside a Lighthouse lab audit.
Core Web VitalsCore Web Vitals are Google's three user-experience metrics: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability.
Web accessibilityWeb accessibility means building sites everyone can use, including people who are blind, deaf, have limited movement or cognitive differences, whatever device or assistive technology they use.
Page speedPage speed is how quickly a web page loads and becomes usable, measured by metrics like Largest Contentful Paint, Interaction to Next Paint and layout stability.
Part of the Web Encyclopedia by Apex Flow Digital. Definitions are general knowledge, kept current, with no invented statistics.