In this context some HTTP responses are static. The static part of the website. But the React app can also start consuming all kinds of webservice. This way

In this context some HTTP responses are static. The static part of the website. But the React app can also start consuming all kinds of webservice. This way (1) a large part of content can be served as prerendered static HTTP responses (HTML, CSS, JS). (2) Static content not initially loaded can be served as JSON (as seen in the presentation). And (3) dynamic content (e.g. real time comments or a chat) can be non-static (one or more webservices, possibly on WebSocket thereby going beyond HTTP). I think this may be very interesting when "big mostly static content", "need for modern web tech" and "big traffic" meet.