The basic problem with SPA is simple: 1) Request handling until you have a functional app in, say PHP: GET Reply (page displays at this point) So: 1 RT happe

The basic problem with SPA is simple: 1) Request handling until you have a functional app in, say PHP: GET Reply (page displays at this point) So: 1 RT happens. 2) In an SPA GET the html reply Get the javascript reply Get javascript dependencies (usually multiple) replies Get the data to display (again usually multiple requests, because nobody does the call combining you should do (ie. don't have GetUserData(), GetFrontpageItems(), GetMessages(). Instead have GetAllStartupStuff() that returns all 3, to avoid the extra roundtrips) reply So: 4 RT Minimum Guess which is the overriding cost in any webapp ? Yep, the roundtrip. Guess why we do this SPA thing ? Why, we do it because it's faster, of course ! (this is so ridiculous it's sad)