Part of the complaints about MPAs originally was that navigating all the different pages was slow, because loading new pages was slow. But plenty of today's SPAs deliver content even slower and the user is staring at a spinner for lengthy stretches. The key is quick, efficient server responses, whether using SPA or MPA approaches.

Yeah. In theory SPAs should be faster, but in practice rendering/sending the whole template is not as bad. And as you mention, both can be slow, due to the non-cached API/DB call, so...

Even in theory, producing json is just typically slower than producing HTML.

It seems unintuitive, but traversing an object tree using reflection to generate json is just slower than using an HTML template, which is probably a rope data structure.

Rendering the template or JSON response is the last and probably often the least computationally expensive step though.

I guess the rendering itself is pretty much the same for both SPAs and MPAs, since in the end it can be pretty much the same markup, but the SPA is also at a disadvantage here because it has to combine template/components + JSON to generate the HTML :/

That reminds me of when I first benchmarked a Rails app and noticed that JSON rendering was significantly slower than the remote database call. No lie, jbuilder was taking about 80% of the request time for about 90% of all endpoints.

Oh, totally. I myself have written on how GitHub manages to make client side navigation 2x slower than full page reload: https://yoyo-code.com/why-is-github-ui-getting-so-much-slowe...

great article!

Issues with old school websites before SPAs were usually "kinda clunky/hard to navigate/find stuff" and "ugly/inconsistent UI."

Issues with SPAs are "core features straight up don't work " and "page is now just an endless spinner."

I know which I prefer.