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Raj Aryan
Raj Aryan

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🚀 Your Next.js App Feels Laggy? Here’s How I Made Mine 10x Faster — No BS!

#webdev #programming #javascript #beginners

✨ If your Next.js app looks modern but feels slow… users will bounce before the hero section loads. Let’s fix that.

When I started using Next.js, I loved the developer experience — hybrid rendering, API routes, image optimization — all of it.

But when my pages started feeling bloated, load times spiked, and Lighthouse screamed at me, I knew I had to optimize seriously.

After some trial (and painful errors), here’s the no-fluff guide I used to speed up my Next.js app — and you can too.

✅ 1. Dynamic Imports: Don’t Load the Whole House at Once 

import dynamic from 'next/dynamic';

const Chart = dynamic(() => import('../components/Chart'), {
  ssr: false,
  loading: () => <div>Loading...</div>,
});
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If a component is not needed right away — don’t load it right away. This shaves off KBs from the initial JS bundle and improves First Contentful Paint (FCP).

🧠 2. Use next/image Instead of <img> 

import Image from 'next/image';

<Image
  src="/team.jpg"
  alt="Team"
  width={600}
  height={400}
/>
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Benefits:

  • Lazy loading ✅
  • WebP support ✅
  • Responsive resizing ✅

It’s a low-effort, high-reward optimization. Native image handling FTW.

📆 3. Analyze Your Bundle (and Kill Bloat) 

npm install @next/bundle-analyzer
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Then update your next.config.js:

const withBundleAnalyzer = require('@next/bundle-analyzer')({ enabled: true });

module.exports = withBundleAnalyzer({
  reactStrictMode: true,
});
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Visit /analyze after build and see what’s killing your performance. Libraries like lodash, moment, or giant icons? Time to tree-shake or replace them.

💡 4. Use SWR or React Query for Smart Data Fetching 

import useSWR from 'swr';

const fetcher = (url) => fetch(url).then(res => res.json());
const { data, error } = useSWR('/api/user', fetcher);
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✅ Built-in caching
✅ Revalidation
✅ Lightweight

Don’t refetch everything on every click.

🧼 5. Remove Unused CSS and JS

  • Use Tailwind’s purge feature to clean CSS
  • Avoid global CSS unless necessary
  • Import icons/components individually, not the full lib: 
// Good
import { FaGithub } from 'react-icons/fa';
// Bad
import * as Icons from 'react-icons';
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💾 6. Prefer getStaticProps Over SSR 

export async function getStaticProps() {
  const res = await fetch('https://api.example.com/data');
  const data = await res.json();

  return { props: { data }, revalidate: 60 };
}
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Static Site Generation (SSG) is faster and cheaper — use Server-Side Rendering (SSR) only when you must.

⛔ 7. Disable JavaScript Where You Don’t Need It

If a page is purely static, add:

export const config = {
  unstable_runtimeJS: false
}
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This removes JS from the page entirely — perfect for marketing, terms, or static blogs.

🌍 8. Use CDN and Proper Caching

Deploy on Vercel, Cloudflare, or Netlify to get:

  • Edge caching
  • Geo-routing
  • Headers control (Cache-Control, ETag, stale-while-revalidate)

Your global users will thank you.

🧵 Final Thoughts

Speed is a feature.

A fast app feels polished, earns trust, boosts SEO, and increases conversions.

Don’t settle for “it loads fine on my machine.” Optimize your Next.js app — your users deserve smooth, snappy performance.

🗅 Bonus Checklist

  • [ ] Dynamic imports
  • [ ] Bundle analyzer run
  • [ ] next/image in place
  • [ ] SWR or React Query used
  • [ ] getStaticProps > SSR
  • [ ] CSS purged and tree-shaking done
  • [ ] CDN + Cache headers set

💬 Let me know what else you’re doing to optimize your frontend — or drop your favorite tool/plugin in the comments.

🔁 If you found this helpful, share with your dev team and help others escape the lag spiral.

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