Ah the wonders of SPA! I know there are lighter ones, but it is not the first time hearing things like React being slow. Of course, when one start to do sntax highlighting on the client side....
Now you CAN so it so that is not the case, but tbh i have never seen that in the wild -
Edit: here's a good investigation on a real-enough app https://www.developerway.com/posts/tailwind-vs-linaria-perfo...
Tailwind is probably one of the best considering you can use Vite to literally strip out all unused css easily.
And I think tailwind v4 does this automatically
This is such a tired trope.
The reality is both can be slow, it depends on your data access patterns, network usage, and architecture.
But the other reality is that SPAs and REST APIs just usually have less optimal network usage and much worse data access patterns than traditional DB connected SSR monoliths. Same goes for micro service.
Like, you could design a highly scalable and optimal SPA. Who's doing it? Almost nobody.
No, instead they're making basically one endpoint per DB table, recreating SQL queries in client side memory, duplicating complex business logic on the front and back end, and sending 50 requests to load an dashboard.
Even other frameworks like Vue.js, Solid or Svelte don't really suffer from it as much. It simply happens a couple order of magnitudes more often in React than any other framework.