Module 3 · 1 chapters

Web Performance

Web performance is not one trick — it is a stack of measurable optimizations aligned to Core Web Vitals. LCP measures loading, INP measures responsiveness, and CLS measures visual stability.

This module covers the fix techniques, code patterns, and tooling interviewers expect at SDE-2 level: from preloading LCP images to breaking up long tasks, from Brotli compression to Lighthouse performance budgets.

You will learn how to read a Lighthouse report, set performance budgets, prioritize fixes by Web Vitals impact, and explain the difference between lab data and real-user monitoring in production.

Topics include image lazy-loading and responsive srcset, code splitting and tree shaking, font loading strategies, CDN caching, and breaking long tasks that hurt INP on low-end devices.

Chapters in this module

  1. Web PerformanceThe three Core Web Vitals — LCP, INP, and CLS — plus Critical Rendering Path optimization, image/JS/CSS/network tuning, and performance measurement tools for production-grade frontend engineering.
Start with Web Performance