Why Performance Matters
Every 100ms of latency costs 1% in conversions. For Next.js applications, performance optimization isn't just a nice-to-have—it's essential for business success.
Core Web Vitals
Google's Core Web Vitals are the key metrics to optimize: LCP (Largest Contentful Paint) should be under 2.5 seconds, FID (First Input Delay) under 100 milliseconds, and CLS (Cumulative Layout Shift) under 0.1.
Image Optimization
Next.js Image component is your best friend. Use priority for above-the-fold images, leverage automatic WebP conversion, and set explicit width/height to prevent CLS.
Code Splitting
Next.js automatically code-splits by route, but you can go further with dynamic imports. Use next/dynamic for heavy components that aren't needed immediately.
Caching Strategies
Implement aggressive caching: Static pages with ISR, API routes with Cache-Control headers, and CDN caching at the edge.
Results You Can Expect
With proper optimization, expect 40-60% improvement in LCP, 80%+ improvement in FID, and near-zero CLS. Your Next.js app can achieve Lighthouse scores of 95+ with these techniques.