PageSpeed Matters
    See Plans & Pricing
    See Plans & Pricing
    PageSpeed Matters
    See Plans & Pricing
    Optimization Techniques · Glossary

    Lazy Loading

    Matt SuffolettoWritten by Matt Suffoletto
    Published June 26, 2026
    Lazy Loading
    Share

    TL;DR

    Lazy loading is a pattern that defers the loading of non-critical resources, typically below-the-fold images, iframes, and JavaScript modules, until they are about to enter the viewport or are explicitly requested.

    What is Lazy Loading?

    Lazy loading is a pattern that defers the loading of non-critical resources, typically below-the-fold images, iframes, and JavaScript modules, until they are about to enter the viewport or are explicitly requested.

    Learn more in our how to improve lazy loading guide, or work with us through our done-for-you speed optimization service.

    How Lazy Loading is Measured

    Native lazy loading is enabled with the loading="lazy" attribute on <img> and <iframe>, and is auditable in PageSpeed Insights.

    Related Terms

    Sources