What is Lazy loading?
The short answer
Lazy loading delays downloading images, video, scripts or components until they are about to be needed, usually when they scroll into view.
Lazy loading, explained
It speeds up the first view. The one exception is the main hero image, which should load eagerly because it is often the Largest Contentful Paint.
Questions people ask about Lazy loading
What is Lazy loading?
Lazy loading delays downloading images, video, scripts or components until they are about to be needed, usually when they scroll into view.
Related terms
Code splitting breaks a site's JavaScript into smaller chunks so each page downloads only the code it needs, loading the rest on demand.
Image optimisationImage optimisation is serving images at the right size, format and quality for each device, so pages load fast without visibly losing quality.
Largest Contentful PaintLargest Contentful Paint measures how long it takes for the largest visible element, usually the hero image or headline, to appear; good is 2.5 seconds or less.
DOMThe DOM is the browser's live, tree-shaped model of a web page; JavaScript reads and changes the DOM to update what visitors see.
Part of the Web Encyclopedia by Apex Flow Digital. Definitions are general knowledge, kept current, with no invented statistics.