Optimizing Next.js for Core Web Vitals

Performance isn't a one-time task. On every client handoff, I run Lighthouse, check Core Web Vitals, and fix the issues that affect real users — not just the audit score.

The checklist I use

Images

• Use next/image with explicit width / height
• Serve WebP/AVIF where possible
• Lazy-load below-the-fold media
• Don't ship 4000px hero images for a 1200px container

JavaScript

• Dynamic import heavy components (carousels, charts, animation libs)
• Avoid shipping GSAP ScrollTrigger on pages that don't use it
• Keep client components small — push data fetching to the server

const ProjectGallery = dynamic(
  () => import("./project-gallery").then((m) => m.ProjectGallery),
  { ssr: false }
)

Fonts

• Subset fonts to needed characters
• Use display: swap to avoid invisible text during load
• Limit font families — two is usually enough

Caching

• Set sensible revalidate for CMS-backed pages
• Cache static assets with long TTL at the CDN layer
• Don't re-fetch unchanged WordPress data on every request

Metrics I watch

Real project example

On a multilingual tour-booking platform, I improved PageSpeed by combining image optimization, code splitting, and deferring non-critical scripts. The site targeted international tourists on mobile networks — every 100ms matters.

Final thought

Chasing a perfect Lighthouse score is less important than fixing what users feel: slow heroes, janky scroll, and layout shifts on load.

Start with images and JavaScript bundle size. That alone fixes most problems.