Prefetching in Next.js Links Explained

🚦 What is prefetch?#

In Next.js, <Link> can prefetch the code + data for the target page before you click.
That means when the user actually clicks, navigation feels instant.

⚙️ How it works under the hood#

1. When a <Link> appears in the viewport, Next.js triggers a prefetch request:

   • The JavaScript bundle for that route.
   • In App Router (/app), also the React Server Component (RSC) payload.

2. Prefetching uses an IntersectionObserver so links outside the screen aren’t prefetched unnecessarily.

3. If you hover/focus a link, Next.js may also prefetch aggressively.

4. When you click, Next.js already has the assets in the router cache, so navigation happens with zero extra network latency.

🛠 Usage#

import Link from "next/link";

export default function Home() {
  return (
    <nav>
      {/* Prefetch ON (default in production) */}
      <Link href="/about">About</Link>

      {/* Explicitly disable prefetch */}
      <Link href="/contact" prefetch={false}>
        Contact
      </Link>
    </nav>
  );
}

• ✅ Default in production: <Link> prefetches.
• ⚠️ Development mode: Prefetching is disabled (to avoid interfering with HMR).

📦 App Router specifics (Next.js 13+)#

• Prefetch loads both the code bundle and the RSC payload (.rsc file).
• These are stored in the Router cache, so clicking doesn’t trigger a new fetch unless stale.
• With fetch inside Server Components, cache control (force-cache, no-store) determines whether the prefetched data is reused or refetched.

🎯 When to disable prefetch#

• If you render too many links (e.g., a large list/table), prefetching all would waste bandwidth.
• In those cases, use prefetch={false} or dynamically load links only when visible.

🧠 Mental model#

• <Link prefetch> = “warm up the router with everything this page needs, before the user clicks.”
• This is why Next.js apps often feel faster than plain SPAs: navigation happens instantly, without waiting for the network.

✅ Summary#

• Next.js prefetch loads JS bundles + data when a link is visible.
• Prefetch is enabled by default in production.
• Use prefetch={false} when you have many links and want to avoid wasted requests.
• In App Router, prefetch also warms up the RSC payload in the router cache.

✨ Result: smoother, almost instant page transitions.