Lazy Loading

Lazy loading is a performance optimization technique that defers the loading of non-critical resources — typically images and iframes below the fold — until they are about to enter the viewport, reducing initial page load time and data consumption. Native lazy loading is supported in modern browsers via the loading="lazy" HTML attribute.

Lazy loading impact on Core Web Vitals is measured using Google Lighthouse and PageSpeed Insights, which track LCP and CLS scores. Proper lazy loading implementation must ensure that above-the-fold images and LCP elements are not lazily loaded, as this would negatively impact performance scores visible in Google Search Console.