Suspense & Streaming

Suspense boundaries allow parts of the UI to stream independently in App Router.

Suspense with RSC

• Server streams ready parts of the tree as they finish.
• Slow components or fetches show fallbacks.
• RSC payload arrives in steps.

Automatic boundaries

• Around segments with loading.js.
• Around nested layouts and dynamic segments.
• Enables partial UI while slower parts load.

Streaming behavior

• Server sends HTML and RSC in chunks.
• Client renders minimal HTML first, then updates with fragments.

Suspense in Client Components

Suspense works on the client but without RSC streaming.

<Suspense fallback={<Spinner />}>
  <Chart />
</Suspense>

Why it matters

• Faster perceived load.
• Parallel rendering for large layout trees.