🚀 Frontend Performance Guide (React / Web)

Performance is not just about making things fast — it’s about making them feel fast . In real-world applications, users don’t care if your API takes 300ms or 800ms. They care about: How quickly content appears Whether the UI feels responsive If things jump around unexpectedly That’s why frontend performance should be approached in three layers : 👉 Network → Rendering → User Perception And validated using: 👉 Core Web Vitals: LCP, CLS, INP 1. Network Optimization Network is the first bottleneck . Before React even runs, the browser must download HTML, CSS, JS, images, and fonts. The goal here is simple: 👉 Send less data, and send it only when needed Route-based Code Splitting Instead of shipping your entire app in one bundle, you split it by routes. This ensures users only download code for the page they visit. import { lazy , Suspense } from ' react ' ; import { Routes , Route } from ' react-router-dom ' ; const Dashboard = lazy (() => import ( ' ./pages/Dashboard ' )); const Profile =