Next.js 15 Partial Prerendering (PPR) Under the Hood: Zero-JS Shells with Instant Streaming

The Next Frontier of Web Rendering: PPR

For years, web developers were forced to choose between Static Site Generation (SSG) for lightning-fast TTFB and Server-Side Rendering (SSR) for real-time dynamic user state.

Next.js 15 with React 19's Partial Prerendering (PPR) unifies both paradigms into a single unified request lifecycle.

How PPR Works

1. Build Time: The static shell (navigation, footer, layout skeletons) is pre-rendered and distributed to edge CDNs.
2. Request Time: The CDN immediately streams the pre-rendered HTML shell to the browser within <20ms.
3. Async Streaming: Dynamic Suspense boundaries on the server execute async database queries and stream the resolved React Flight packets directly into the open connection.

Zero-JS Static Footprint

Because server components within the static shell execute only at build or edge time, their dependencies (date formatting libraries, markdown parsers) contribute zero bytes to the client JavaScript bundle.