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PerformanceMarch 20265 min read

Frontend Performance Optimization Tips

Why Performance Matters


Performance is not just a technical metric — it directly impacts user experience, SEO rankings, and conversion rates. A 1-second delay in page load can reduce conversions by 7%.


Core Web Vitals


Google uses three key metrics to measure performance:


  • LCP (Largest Contentful Paint) — measures loading performance. Target: under 2.5s
  • FID (First Input Delay) — measures interactivity. Target: under 100ms
  • CLS (Cumulative Layout Shift) — measures visual stability. Target: under 0.1

  • Practical Tips


    1. Optimize Images

    Always use modern formats like WebP or AVIF. Use lazy loading for below-the-fold images. Always define width and height to avoid layout shifts.


    2. Reduce JavaScript Bundle

    Code split your application. Use dynamic imports for heavy components. Remove unused dependencies regularly.


    3. Use a CDN

    Serve static assets from a CDN close to your users. Vercel does this automatically for Next.js apps.


    4. Minimize Render Blocking

    Load non-critical CSS and JS asynchronously. Use resource hints like preload and prefetch strategically.


    5. Cache Aggressively

    Set proper cache headers for static assets. Use service workers for offline caching where appropriate.


    Tools to Measure


  • Google PageSpeed Insights
  • Chrome DevTools Lighthouse
  • WebPageTest
  • Core Web Vitals report in Google Search Console
  • SC
    Sandip Chavda
    Frontend Engineering Lead · Mumbai
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