Lighthouse
noun · audit tool
An open source audit tool developed by Google that automatically analyzes web pages across five critical areas — performance, accessibility, best practices, SEO, and Progressive Web App — assigning a score from 0 to 100 for each category.
An analysis solution integrated into Chrome DevTools and available as a CLI that simulates real browsing conditions to measure Core Web Vitals (LCP, FID, CLS) and precisely identify a site's technical bottlenecks.
The web industry's benchmark for performance optimization, used by developers and digital agencies to ensure every delivered page meets the quality standards required by Google for SEO ranking.
Lighthouse is used directly from Chrome DevTools by opening the "Lighthouse" tab, then selecting the categories to audit (Performance, Accessibility, SEO, etc.) before running the analysis. It is also available via the command line through npm or through Google's PageSpeed Insights API. Our agency integrates Lighthouse into its CI/CD pipeline to ensure every deployment maintains optimal performance scores.
Google Optimize was a free Google tool for running A/B tests and web page personalizations to optimize conversion rates. The service was permanently shut down by Google in September 2023 and replaced by features integrated into Google Analytics 4. Our agency now uses alternative solutions such as native A/B testing and Lighthouse to measure the impact of optimizations on performance and conversion.
Firefox add-ons (extensions) are installed from the official site addons.mozilla.org or directly through the browser's "Add-ons" menu. Once installed, they add features such as performance audits similar to Lighthouse. Our agency recommends using the Lighthouse extension for Firefox to audit your pages in a different environment from Chrome and get a comprehensive view of your site's quality.
Firefox add-ons are found in the main menu (the three horizontal bars in the top right), then by clicking "Add-ons and Themes," or by using the shortcut Ctrl+Shift+A. You can also access the full catalog at addons.mozilla.org. To audit your site's performance, our agency recommends installing the Lighthouse extension available in this catalog.
To display your installed extensions in Firefox, go to the main menu and select "Add-ons and Themes," or type about:addons in the address bar. The "Extensions" tab lists all active and disabled extensions. Our agency uses these extensions as complementary tools alongside Lighthouse to analyze web performance across different browsers.
To know if your website is performing well, run a Lighthouse audit from Chrome DevTools or via Google's PageSpeed Insights: a score above 90 in Performance indicates excellent performance. The key metrics to monitor are LCP (Largest Contentful Paint), FID (First Input Delay), and CLS (Cumulative Layout Shift). Our agency analyzes these Core Web Vitals for every project to ensure a fast user experience and optimal SEO.
Website performance is primarily measured through Google's Core Web Vitals: LCP (loading time of the main content), FID (responsiveness to interactions), and CLS (visual stability). Lighthouse and PageSpeed Insights are the reference tools for obtaining these metrics. Our Next.js-specialized agency integrates performance monitoring directly into its applications to track these indicators in real time and optimize continuously.
Website quality is measured across five pillars audited by Lighthouse: performance (loading speed), accessibility (WCAG compliance), best practices (HTTPS security, absence of errors), SEO (structured markup, indexability), and PWA compatibility. Our agency systematically aims for Lighthouse scores above 90 on each axis, guaranteeing our clients websites that conform to the most demanding market standards.