Next.js, The Docs: Understanding Loading and Streaming

Currently Reading: Loading UI and Streaming

When building a dynamic web application, ensuring smooth and responsive user interactions is key. Next.js provides an elegant solution to enhance user experience with Loading UI and Streaming. These features make content delivery faster and more seamless, ensuring users don't feel like they're waiting long for pages to load.

Loading UI: This feature allows you to display an immediate loading state (like a spinner or skeleton UI) while the content of a route segment loads in the background. The loading.js file helps manage this by showing instant feedback, so users know the app is responding. For example, it can be a cover photo or a minimal layout that appears instantly, while the full content loads progressively. This setup ensures your app feels responsive even when data fetching takes some time.

Streaming: Streaming breaks down the content of your page into smaller chunks that are progressively sent from the server to the client. This means parts of the page can load and display as soon as they’re ready, rather than waiting for the entire page's content to be fetched. This significantly improves performance by reducing the Time to First Byte (TTFB) and First Contentful Paint (FCP), especially on slower networks or devices. Suspense components manage this process by rendering placeholders for chunks that are still loading, and replacing them with actual content once they’re ready.

To learn more in-depth about how to implement these features, check out the Next.js documentation on Loading UI and Streaming.

By leveraging Loading UI and Streaming in your Next.js applications, you can ensure your users experience faster, smoother, and more interactive page loads.