Lighthouse Audit: Understanding and Improving Your Scores

Learn how to use Lighthouse audits to improve performance, accessibility, and SEO.

Lighthouse Audit: Understanding and Improving Your Scores

What is Lighthouse?

Lighthouse is an open-source, automated tool developed by Google for improving web page quality. It audits performance, accessibility, SEO, and best practices.

Lighthouse Categories

Performance (0-100)

Measures how fast your page loads and becomes interactive.

Accessibility (0-100)

Checks how accessible your page is to users with disabilities.

Best Practices (0-100)

Evaluates modern web development practices.

SEO (0-100)

Checks basic search engine optimization.

PWA

Validates Progressive Web App requirements.

Understanding Performance Metrics

Key Metrics Weighted

| Metric | Weight |

|--------|--------|

| Total Blocking Time | 30% |

| Largest Contentful Paint | 25% |

| Cumulative Layout Shift | 25% |

| First Contentful Paint | 10% |

| Speed Index | 10% |

Running Lighthouse Audits

Chrome DevTools

  • Open DevTools (F12)
  • Go to Lighthouse tab
  • Select categories
  • Click "Generate report"

    • Command Line

    ``bash

    npx lighthouse https://example.com --view

    ``

    PageSpeed Insights

    Visit pagespeed.web.dev for combined lab and field data.

    Improving Your Scores

    Quick Wins

  • Compress images to WebP
  • Enable text compression
  • Remove unused CSS/JS
  • Defer non-critical resources

    • Advanced Optimizations

  • Implement code splitting
  • Use service worker for caching
  • Optimize critical rendering path
  • Reduce third-party impact

    • Run a Lighthouse audit with our free performance tool.