Streaming SSR lets the server send HTML to the browser in chunks as it's ready, instead of waiting for the entire page to render. Slow parts don't block fast parts — the user sees content progressively. React <Suspense> defines the streaming boundaries.
The problem streaming solves
Without streaming, if one section needs a slow database query, the waits for it before HTML is sent — the user stares at a blank screen. Streaming sends the shell and fast content immediately, then streams the slow parts as they finish.
