The open web is a constantly evolving place. I built my first websites with the classic LAMP stack, basic HTML and CSS files with JQuery sprinkled into. Lately, we see more and more of our publishers moving or already using some sort of client-side rendering. Initially this was coined as SPA, single page application, as the browser would only load a single page once and all navigation would just replace parts of the page by fetching data from a server and alter the UI with it.