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Website Performance Guide

Complete guide to web performance: Core Web Vitals, image optimization, caching, and code splitting.

Web performance has three pillars measured by Core Web Vitals: LCP (Largest Contentful Paint — how fast the main content loads, target < 2.5s), FID/INP (interaction delay — how fast the page responds to clicks, target < 200ms), and CLS (Cumulative Layout Shift — how much the page jumps during loading, target < 0.1). The highest-impact optimizations: compress and properly size images (saves 50% of page weight), use a CDN (reduces latency by 100-300ms), enable caching headers (eliminates repeat downloads), code-split JavaScript (only load what is needed), and use static generation where possible (serve pre-built HTML instead of server-rendering on each request).