Frontend Performance Guide

Frontend Performance Guide A hands-on optimization playbook for achieving perfect Core Web Vitals scores in React and Next.js applications. Covers every performance lever: code splitting, image optimization, caching strategies, bundle analysis, font loading, third-party script management, and runtime profiling. Each technique includes before/after metrics, implementation code, and a decision tree for when to apply it. Key Features Core Web Vitals Deep Dive — Breakdown of LCP, INP, and CLS with specific code patterns that improve each metric Code Splitting Strategies — Route-based splitting, component-level lazy loading, and barrel file elimination Image Optimization — next/image configuration, responsive srcsets, WebP/AVIF format selection, and priority loading Caching Architecture — CDN headers, SWR patterns, service worker precaching, and ISR revalidation Bundle Analysis Tools — Webpack Bundle Analyzer config, size budget enforcement in CI, and tree-shaking verification Font Loading