Next.js 16.3 preview adds instant navigations and partial prefetching

Next.js 16.3 preview introduces Instant Navigations, enabling server-driven apps to offer instant, SPA-like page transitions.

The release also debuts partial prefetching, which fetches and caches reusable page shells per route, reducing redundant network requests.

Developers must enable the Cache Components flag to use these features and can choose between streaming, caching, or blocking server data fetches for each navigation.