[Scarbutt]

The issue here is nodejs, react ssr is costly, taking all you cpu time, blocking the event loop and slowing down your app. On a multi-threaded (async or sync) web server this wouldn't be a issue most of the time.

Some add additional nodejs servers specifically and only for SSR, increasing complexity.

airbnb created https://github.com/airbnb/hypernova to solve exactly this problem.