Problem Statement
Explain how streaming and Suspense work together in App Router for progressive rendering.
Explanation
Streaming allows Next.js to progressively send rendered HTML chunks to the browser as they become ready rather than waiting for the entire page to render, dramatically improving Time to First Byte and perceived performance.
Server Components are rendered to a special format that streams to the client, and Suspense boundaries define stream boundaries where content inside the boundary can load asynchronously while the rest of the page renders immediately.
When a Server Component suspends for async data fetching, Next.js streams the fallback UI immediately, continues rendering other components, and streams in the resolved content when ready, all without blocking the initial response.
This enables showing instant page shells with loading states while expensive data fetches complete, particularly effective for slow database queries, third-party API calls, or large datasets where users see content progressively rather than staring at a blank page, resulting in better engagement and perceived performance even with identical actual load times.
Practice Sets
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