Lighthouse
A free tool in Chrome DevTools that audits a page's performance, accessibility, SEO and best practices.
Definition
Lighthouse loads a page, measures it and gives scores from 0 to 100 with a list of concrete problems. Scores vary between runs and machines, so testers compare runs under the same conditions and focus on the specific findings.
In practice
Lighthouse reports that images on the home page are 4 MB each and that buttons have no accessible name.
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Related terms
- Core Web VitalsGoogle's key page experience metrics: loading (LCP), responsiveness (INP) and visual stability (CLS).
- Accessibility testingChecking that people with disabilities can use the product, for example with a screen reader.
- DevToolsDeveloper tools built into browsers for inspecting pages, network traffic and errors.