Comparison

Google Lighthouse vs PageSpeed Insights

Understand the differences between Google Lighthouse and PageSpeed Insights. Learn when to use each tool and how they relate to your Core Web Vitals scores.

Google Lighthouse

Developers debugging performance during development and CI/CD integration

5 pros4 cons

PageSpeed Insights

Site owners checking how Google sees their Core Web Vitals in production

5 pros4 cons

Detailed Comparison

Google Lighthouse Pros

  • Run locally in Chrome DevTools
  • Full control over test environment
  • Detailed source-mapped debugging
  • Works on localhost and staging
  • Direct integration with CI/CD

PageSpeed Insights Pros

  • Includes real CrUX field data
  • Consistent test environment
  • No setup required - just enter URL
  • Shows what Google actually measures
  • Mobile and desktop results together

Google Lighthouse Cons

  • Lab data only - no field data
  • Results vary by machine specs
  • Requires Chrome or CLI setup
  • No historical tracking built-in

PageSpeed Insights Cons

  • Only works on public URLs
  • Less control over test conditions
  • No localhost testing
  • Simplified recommendations

Our Verdict

Lighthouse and PageSpeed Insights use the same underlying engine, but serve different purposes. Use Lighthouse during development for debugging and CI/CD. Use PageSpeed Insights to check production scores and see real-world field data. Both are free Google tools that complement each other.

Frequently Asked Questions

Scores differ because Lighthouse runs on your machine (affected by your CPU, memory, and network) while PSI runs on Google's standardized servers. PSI also shows field data which may differ from lab scores based on actual user conditions.
Google uses field data (CrUX) for Core Web Vitals ranking signals, which PSI displays when available. If your site doesn't have enough traffic for CrUX data, Google may use origin-level or lab data. The key metrics are LCP, CLS, and INP.
Yes, Lighthouse in Chrome DevTools can test any page you can access in the browser, including authenticated pages and localhost. PageSpeed Insights cannot test pages behind authentication since it runs remotely.
Run Lighthouse during development and in CI/CD for every deploy. Check PageSpeed Insights weekly or after major changes to monitor field data. Remember that CrUX field data updates on a 28-day rolling basis.

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