Web Performance Optimization Techniques

Performance is crucial for user experience and SEO. Here are proven techniques to optimize your web applications.

Image Optimization

Images often account for the largest portion of page weight:

<!-- Use modern formats -->
<picture>
  <source srcset="image.avif" type="image/avif" />
  <source srcset="image.webp" type="image/webp" />
  <img src="image.jpg" alt="Description" loading="lazy" />
</picture>

Code Splitting

Split your JavaScript bundles to load only what’s needed:

// Lazy load components
const HeavyComponent = lazy(() => import("./HeavyComponent"));

function App() {
  return (
    <Suspense fallback={<Loading />}>
      <HeavyComponent />
    </Suspense>
  );
}

Caching Strategies

Implement proper caching headers:

// Service Worker caching
self.addEventListener("fetch", (event) => {
  event.respondWith(
    caches.match(event.request).then((response) => {
      return response || fetch(event.request);
    })
  );
});

Minimize Render-Blocking Resources

Defer non-critical CSS and JavaScript:

<!-- Defer non-critical CSS -->
<link
  rel="preload"
  href="styles.css"
  as="style"
  onload="this.onload=null;this.rel='stylesheet'"
/>

<!-- Defer JavaScript -->
<script src="app.js" defer></script>

Use CDN for Static Assets

Serve static assets from a Content Delivery Network:

<link rel="stylesheet" href="https://cdn.example.com/styles.css" />

Monitor Performance

Use tools like Lighthouse and Web Vitals:

• LCP (Largest Contentful Paint) - Aim for < 2.5s
• FID (First Input Delay) - Aim for < 100ms
• CLS (Cumulative Layout Shift) - Aim for < 0.1

Conclusion

Performance optimization is an iterative process. Measure, optimize, and measure again. Small improvements compound into significant gains!