Lazy Loading Strategies Beyond Images

Lazy loading images with loading='lazy' is table stakes — every developer knows that trick. But the real performance wins come from applying lazy loading principles to everything: components, routes, third-party scripts, and even data fetching strategies.

React's lazy() and Suspense make component-level code splitting straightforward. Heavy components like rich text editors, charts, and maps should always be dynamically imported. The key is identifying the right split points — components that aren't visible on initial load or require user interaction.

Route-based code splitting is handled automatically by Next.js, but you can go further. Use dynamic imports for modal contents, tab panels, and accordion sections. Each split point reduces the initial JavaScript payload, improving Time to Interactive.

Third-party scripts are often the biggest offenders. Analytics, chat widgets, social embeds, and advertising scripts can easily add 500KB+ to your bundle. Load them with requestIdleCallback or intersection observer triggers — only when the browser is idle or when the relevant section scrolls into view.

Data fetching can be lazy too. Instead of loading all data upfront, implement pagination, infinite scroll, or fetch-on-reveal patterns. Combined with React Server Components that stream HTML, you can create interfaces that feel instant even with large datasets.