Responding with JSON from Node.js servers enables API development and data exchange between client and server applications with proper content formatting. As the creator of CoreUI, a widely used open-source UI library, I’ve built countless Node.js APIs that serve JSON responses for frontend applications and data integrations. From my expertise, the most effective approach is using Express.js res.json() method for automatic JSON serialization and proper headers. This method ensures correct content-type headers and handles JSON conversion seamlessly for reliable API responses.