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What is loading.js in Next.js and how does Suspense streaming work?

Q: What is loading.js in Next.js and how does Suspense streaming work?

**TL;DR.** Adding loading.js wraps the segment in a **Suspense boundary**, so Next.js **streams an instant fallback** while the Server Component fetches data, then **streams in** the real content when it's ready — improving perceived performance with no manual Suspense wiring. shell + loading sent instantly data resolves content streamed <text class='d-sub' x='277' y='90' text-anc

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Instant loading UI via automatic Suspense boundaries.

nextjsloadingsuspensestreaming

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Instant loading UI

// app/dashboard/loading.tsx — streamed instantly
export default function Loading() {
  return <div className="skeleton">Loading dashboard…</div>;
}

// app/dashboard/page.tsx — slow data; user sees Loading first
export default async function Page() {
  const data = await getSlowReport();    // streams in when ready
  return <Report data={data} />;
}

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