Shipping fast with React Server Components

The boundary is the architecture

The single most important decision in an RSC app is *where the "use client" line goes*.

Rules of thumb

• Fetch on the server; hydrate only what needs interaction.
• Push client components to the leaves of the tree.
• Pass serializable props across the boundary — no functions, no class instances.

// Server component
export default async function Page() {
  const posts = await getPosts();
  return <PostList posts={posts} />; // PostList can be a client island
}