Suggest an editImprove this articleRefine the answer for “What does Lighthouse do?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Lighthouse** is a tool from Google that automatically analyzes a web page and produces a performance and quality score across several categories. **Key point:** Lighthouse is an automated site audit for performance, accessibility, SEO, and stability, providing metrics, a report, and recommendations.Shown above the full answer for quick recall.Answer (EN)Image**Lighthouse** is a tool from Google that automatically analyzes a web page and produces a performance and quality score across several categories. --- ### What it checks: 1. **Performance** - LCP, FCP, TTI, TBT, CLS - loading speed, interactivity, layout stability 2. **Accessibility** - text contrast, alt tags, keyboard access, aria attributes 3. **Best Practices** - HTTPS, secure requests, banning unsafe APIs 4. **SEO** - presence of a title tag, meta description, correct indexing, semantics 5. **PWA (Progressive Web App)** - offline mode, manifest, service worker --- ### How it works: - Loads the page like a regular user - Measures key metrics (including Web Vitals) - Checks the DOM, CSS, JS structure, and accessibility - Generates a detailed report with scores and advice --- ### Where to use it: - The Lighthouse tab in Chrome DevTools - Via the CLI (`lighthouse https://site.com`) - Via CI (Lighthouse CI) - Via API integrations or third-party tools (for example, PageSpeed Insights uses Lighthouse internally) --- **Conclusion:** Lighthouse is an automated site audit for performance, accessibility, SEO, and stability. It provides metrics, a report, and recommendations to help you understand what slows the site down and how to fix it.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.