Lighthouse is an automated tool developed by Google that audits web pages for performance, accessibility, progressive web app features, SEO, and best practices. It can be run in Chrome DevTools, as a browser extension, or via command line.
Lighthouse categories
- Performance: Core Web Vitals, load times, and optimization opportunities
- Accessibility: How accessible the page is to users with disabilities
- Best Practices: Modern web development best practices
- SEO: Basic search engine optimization checks
- Progressive Web App: PWA compliance
Lighthouse scores
Each category receives a score from 0-100:
- 0-49: Poor (red)
- 50-89: Needs Improvement (orange)
- 90-100: Good (green)
Lighthouse and Core Web Vitals
Lighthouse measures lab versions of Core Web Vitals:
- LCP (Largest Contentful Paint)
- TBT (Total Blocking Time) - correlates with INP
- CLS (Cumulative Layout Shift)
VitalSentinel and Lighthouse
VitalSentinel runs automated Lighthouse audits on your pages, tracking scores over time and alerting you when performance regresses.
Related Terms
Core Web Vitals
A set of three metrics defined by Google that measure the loading performance, interactivity, and visual stability of a web page.
Lab Data
Performance metrics collected in controlled testing environments using tools like Lighthouse, as opposed to field data from real users.
PageSpeed Insights
A Google tool that analyzes web page content and provides suggestions to make pages faster, combining both lab and field data.
Synthetic Monitoring
A type of performance monitoring that uses automated scripts to simulate user interactions and measure performance in controlled conditions.