Introduction
Lazy loading is the technique of postponing non-critical resource loading until needed. It's essential for improving initial load time and saving bandwidth.
Images with lazy loading
Use native loading="lazy" on <img> and <iframe>. The browser loads the image when it's near the viewport. Native support in all modern browsers.
Dynamic Components
In React, use React.lazy() with Suspense to load components on demand. The component code downloads only when rendered.
Intersection Observer
For custom lazy loading, use Intersection Observer. Detects when an element enters the viewport and triggers data or component loading.
Route lazy loading
Modern frameworks like Next.js, Nuxt, and SvelteKit support automatic route lazy loading. Each route is a separate chunk.
Load Prioritization
Not everything should be lazy. Critical resources must load immediately. Use lazy loading only for content below the initial fold.
Conclusion
Lazy loading is essential for modern web performance. At Vynta, we apply deferred loading patterns to optimize the initial user experience.