This post distills the key ideas from the published DEV article “Frontend Performance Optimization: A Comprehensive Guide 🚀” into a concise, production-focused playbook.

What matters

  • Fast first paint and interaction: prioritize above-the-fold content, cut JS weight, avoid layout shifts.
  • Ship less: smaller bundles, fewer blocking requests, cache aggressively.
  • Ship smarter: load what’s needed when it’s needed (on demand and in priority order).

Core techniques

1) Selective rendering

  • Render only what is visible (e.g., IntersectionObserver + skeletons).
  • Defer heavy components until scrolled into view.

2) Code splitting & dynamic imports

  • Split by route/feature; lazy-load non-critical views.
  • Example (React):
const Page = lazy(() => import("./Page"));
<Suspense fallback={<div>Loading…</div>}>
  <Page />
</Suspense>;

3) Prefetching & caching

  • Prefetch likely-next routes/assets (<link rel="prefetch"> or router prefetch).
  • Pre-warm API data with React Query/Next.js loader functions.

4) Priority-based loading

  • Preload critical CSS/hero imagery: <link rel="preload" as="style" href="styles.css">.
  • Use defer/async for non-critical scripts.

5) Compression & transfer

  • Enable Brotli/Gzip at the edge; pre-compress static assets in CI/CD.
  • Serve modern formats (AVIF/WebP) and keep caching headers long-lived.

6) Loading sequence hygiene

  • Order: HTML → critical CSS → critical JS → images/fonts → analytics.
  • Avoid long main-thread tasks; prefer requestIdleCallback for non-urgent work.

7) Tree shaking & dead-code elimination

  • Use ESM named imports; avoid import *.
  • Keep build in production mode with minification + module side-effects flags.

Measurement & guardrails

  • Track Core Web Vitals (LCP, INP, CLS) plus TTFB and bundle size per release.
  • Run Lighthouse/WebPageTest in CI; fail builds on regressions above agreed budgets.
  • Monitor real-user metrics (RUM) to validate improvements after deploys.

Quick starter checklist

  • Lazy-load routes and heavy widgets.
  • Preload hero font/hero image; inline critical CSS if needed.
  • Turn on Brotli at CDN; cache static assets with versioned filenames.
  • Set performance budgets (JS < 200KB gz, LCP < 2.5s p75, INP < 200ms).
  • Automate audits in CI and watch RUM dashboards after each release.

Bottom line: Combine “ship less” (smaller, shaken, compressed bundles) with “ship smarter” (prioritized, on-demand loading) and enforce budgets with automated checks to keep your app fast over time.