I feel like I gotta call out the LiveView is a bit in a class of its own. HEEx is rendered on the server, but the diff sent over the wire is the absolute minimal diff it can be with a map of where it in the DOM. Often this is just text. LiveView also gives you a running process on the server (a virtual machine process, not a linux process) that holds the user's state (like if they're logged in, for example) and makes things like "who's online?" and other concurrent features almost trivial.