Lazy Loading

Deferring the download of an image or component until it is about to enter the viewport.

Never lazy-load the largest element above the fold; that single mistake makes Largest Contentful Paint worse, not better.

Use the native loading attribute where possible, and keep dimensions on the element so nothing shifts when it arrives.

It cuts initial page weight dramatically on long pages full of media.

Implemented in JavaScript without fallbacks, it can hide content from crawlers entirely.