Understanding Google PageSpeed Insights vs. Lighthouse: Which Should You Use?

When it comes to analyzing and optimizing website performance, Google offers two popular tools: PageSpeed Insights (PSI) and Lighthouse. While both provide valuable insights, they have distinct purposes, data sources, and strengths. Here’s a quick guide to understanding the differences and deciding which tool to use.

What is Google PageSpeed Insights?

PageSpeed Insights (PSI) focuses on website performance, particularly page loading speed and user experience metrics like Core Web Vitals. PSI provides a score based on both lab data (controlled tests) and real-world field data (from the Chrome User Experience Report, or CrUX), offering insights into actual user experiences across different devices and networks.

Use PageSpeed Insights when:

• You need a quick, shareable performance report.
• You want a clear picture of loading speed, including real-world data.
• You prefer an easy, web-based tool without using Chrome DevTools.

What is Google Lighthouse?

Google Lighthouse is a more comprehensive tool that evaluates multiple aspects of a website, including performance, SEO, accessibility, Progressive Web App (PWA) compatibility, and best practices. Lighthouse uses lab data only to create a controlled, consistent testing environment, making it ideal for debugging and pre-launch testing.

Use Lighthouse when:

• You need detailed insights beyond performance, like SEO and accessibility.
• You’re working on pre-launch testing or want to debug specific performance issues.
• You’re comfortable with Chrome DevTools or command-line interfaces.

Key Differences Between PageSpeed Insights and Lighthouse

1. Scope: PSI focuses on performance; Lighthouse covers performance, SEO, accessibility, PWA readiness, and best practices.
2. Data Type: PSI combines real-world (field) and lab data; Lighthouse uses only lab data.
3. Usability: PSI is web-based and user-friendly; Lighthouse is typically used in Chrome DevTools and suits developers looking for in-depth analysis.

Conclusion

Choose PageSpeed Insights for quick, user-friendly insights on real-world performance. Choose Lighthouse for in-depth, lab-based audits covering multiple quality aspects, especially during development. Both tools complement each other and can be used together for a full-picture view of website optimization