## TL;DR

Web performance optimization reduces page load time and improves user experience. Core Web Vitals: LCP (Largest Contentful Paint, <2.5s), INP (Interaction to Next Paint, <200ms, replaces FID in 2024), CLS (Cumulative Layout Shift, <0.1). These metrics directly affect Google search rankings.

## Core Explanation

Optimization techniques: code splitting (dynamic imports), tree shaking (remove unused code), image optimization (WebP/AVIF, srcset, lazy loading), font optimization (font-display: swap, subsetting), CDN, compression (Brotli), caching (Cache-Control headers), critical CSS inlining. Lighthouse and PageSpeed Insights measure and guide improvements.

## Further Reading

- [Web Vitals (Google)](https://web.dev/vitals/)