Lighthouse is an open-source, automated tool developed by Google for improving the quality of web pages.

What it does:

  • Audits performance, accessibility, SEO, best practices, and Progressive Web Apps (PWA).
  • Provides a detailed score (0–100) in each category.
  • Gives actionable recommendations (e.g., image optimization, reducing JavaScript, improving accessibility).

Usage:

  • Built into Google Chrome DevTools.
  • Can be run via the command line or as a Node.js module.

It’s widely used by developers and marketers to enhance user experience, speed, and search engine visibility.