Progressive JSON

Progressive JSON is a streaming approach that sends data breadth-first instead of depth-first, using placeholders that get filled in progressively. Unlike traditional JSON parsing which requires the complete payload, this method allows clients to start processing data as it arrives. The concept mirrors progressive JPEG loading and is implemented in React Server Components, where UI components can display loading states while data streams in. The approach addresses the problem where slow database queries block entire responses, enabling faster perceived performance through incremental data delivery.