Definition
Lighthouse is Google's open-source performance and quality audit tool, integrated into Chrome DevTools and PageSpeed Insights. Scores pages 0-100 on Performance, Accessibility, Best Practices, and SEO. The Performance score weights Core Web Vitals (LCP, INP, CLS) heavily. Magento and Hyvä stores typically target mobile Performance scores of 80 or higher.
What Lighthouse measures
The Performance category combines several signals: Largest Contentful Paint (LCP), Total Blocking Time (TBT), Cumulative Layout Shift (CLS), Interaction to Next Paint (INP), and First Contentful Paint (FCP). Each metric has a target threshold and the aggregate is scored 0-100.
Mobile vs desktop scores
Lighthouse runs separate mobile and desktop audits. Mobile uses a throttled CPU and 4G-like network conditions, so scores are typically 20 to 30 points lower than desktop on the same site. Google's mobile-first indexing means mobile Lighthouse is the score that matters for ranking.
How Magento typically scores
Untouched Luma Magento stores: 30-55 mobile. Optimized Luma: 55-75. Default Hyvä: 80-92. Maintained Hyvä: 85-95. The platform sets the ceiling; discipline determines where within the ceiling you land. See the performance optimization guide for the order of operations.