Performance Optimization for Luxury E-commerce

When Ethereal Fashion approached us, their site scored 34 on Google's Lighthouse performance audit. For a luxury brand where every millisecond of delay costs conversions, this was unacceptable. Six weeks later, we hit a perfect 100/100 — here's exactly how we did it.

The first win was image optimization. Luxury e-commerce depends on stunning visuals, but the original site was serving uncompressed 4K images to mobile devices. We implemented a multi-layered approach: AVIF format with WebP fallback, responsive srcset attributes for device-appropriate sizing, and aggressive lazy loading with blur-up placeholders that maintain the premium feel during load.

Next, we tackled JavaScript. The original site loaded 2.3MB of JavaScript upfront — most of it unused on initial render. We implemented route-based code splitting, moved non-critical scripts to web workers, and replaced heavy animation libraries with CSS animations where possible. The result: initial JS payload dropped to 180KB.

Server-side rendering (SSR) with Next.js was the architectural foundation. Product pages are statically generated at build time and revalidated every 60 seconds, giving us the speed of static sites with the freshness of dynamic content. The CDN edge cache hit rate reached 94%.

Font loading was a subtle but impactful optimization. We subset the brand's custom typeface to include only the characters actually used on the site, preloaded critical font files, and used font-display: optional to prevent layout shift. Total font payload: 28KB, down from 340KB.

The final piece was the perception of speed. Even with all technical optimizations, we added skeleton screens, optimistic UI updates for cart actions, and view transitions for page navigation. Users perceive the site as instant, even when network conditions aren't ideal. The business impact: average order value increased 45% and bounce rate dropped by 60%.