Image Optimization Strategies
Modern image formats like AVIF and WebP deliver superior compression ratios while preserving visual quality. Convert legacy JPEG and PNG assets using automated pipelines in Cloudinary or Squoosh. Apply the srcset attribute and sizes descriptor so browsers select the optimal resolution for each viewport. Add the loading=”lazy” attribute to defer off-screen images, cutting initial payload by 40-60 percent in typical e-commerce pages. Serve responsive hero images at 2x DPR only when connection speed justifies it. Compress further with MozJPEG or libavif at quality 75-85. Replace icon fonts with inline SVGs or CSS masks to eliminate extra HTTP requests. Audit regularly with Lighthouse to keep Largest Contentful Paint under 2.5 seconds.
Code Minification and Bundling
Minify HTML, CSS, and JavaScript during build time with esbuild or Terser. Remove unused code via tree-shaking in webpack or Vite. Bundle critical CSS inline within the head to eliminate render-blocking stylesheets. Defer non-critical JavaScript using defer or async attributes. Split large bundles with dynamic imports so only route-specific code loads. In 2024, adopt Lightning CSS for faster minification and automatic vendor prefixing. Track bundle sizes with webpack-bundle-analyzer and enforce budgets under 170 KB gzipped for mobile.
Compression and HTTP/3
Enable Brotli compression at level 4-6 on the origin server and CDN edge. Brotli typically outperforms Gzip by 15-25 percent on text assets. Activate HTTP/3 and QUIC for multiplexed, 0-RTT connections that reduce handshake latency. Configure servers to advertise Alt-Svc headers. Test with curl –http3 to confirm protocol support. Combine with early hints (103 status) to preload critical fonts and scripts before the HTML response finishes.
Content Delivery Networks
Deploy a global CDN with edge nodes close to users. Cache static assets for 1 year and HTML for 5 minutes using stale-while-revalidate. Enable automatic image optimization and WebP conversion at the edge. Use DNS prefetching and preconnect for third-party domains. Choose providers offering real-time purging and origin shielding to maintain cache hit ratios above 95 percent.
Caching and Resource Hints
Implement service workers for offline-first caching of shell assets. Use Cache-Control: immutable for versioned files. Add resource hints: preload key fonts and LCP images, prefetch likely next-page resources with Speculation Rules API. Set long cache lifetimes on hashed filenames and rely on cache busting for updates. Monitor cache hit rates in CDN dashboards weekly.
JavaScript and CSS Delivery
Extract critical CSS with tools like Critters and inline it. Load remaining CSS asynchronously via media=”print” onload swap. Replace jQuery with lightweight alternatives or native DOM methods. Defer analytics scripts until after user interaction. Use requestIdleCallback for non-urgent tasks. In 2024, adopt View Transitions API to improve perceived speed during navigation.
Server Response and Core Web Vitals
Optimize TTFB by upgrading to PHP 8.3 or Node 20 with OPcache enabled. Use database query caching and Redis for session data. Reduce redirects to zero or one. Measure Interaction to Next Paint with real-user monitoring tools. Target Cumulative Layout Shift below 0.1 by reserving space for images and ads via aspect-ratio CSS.
Monitoring Tools and Continuous Improvement
Run daily Lighthouse CI checks in GitHub Actions. Track Core Web Vitals in Google Search Console and PageSpeed Insights. Set performance budgets in Web Vitals JavaScript library and alert on regressions. Compare 2024 mobile 4G scores against competitors monthly and iterate on the techniques above.