It's not 2010 anymore. Client compute is fast. Server compute is slow and expensive. 4G is ubiquitous and 3G is being phased out.
You can send a tiny amount of JS from a CDN and render on the client. You will save money because the server is efficiently serving JSON instead of doing a gazillion calls and string interpolation per request. The user won't notice.
Also, now that the server is responding with JSON it doesn't need to run any JS at all, so you can rewrite the server in an even more efficient language and save even more money.
> It's not 2010 anymore. Client compute is fast.
It's not: https://infrequently.org/2025/11/performance-inequality-gap-...
Yes it is. Even a cheap Xiaomi is fast enough to render any application you can think of.
React is not the bottleneck. The bottleneck is all the bloat in the application code.
Webdevs act as if optimization isn't a thing and the only solution to any performance issue is to add more hardware. This explains the popularity of server-side rendering: it's a way of solving a performance issue by "adding more hardware" to the user's phone.
Yet, the user's phone was always perfectly capable of doing what they needed it to do. The problem is their application code is an unoptimized turd. They could optimize it but that would be work. Fortunately, a helpful cloud computing service has the solution: just offload your unoptimized turd to servers in the cloud!
"Sounds fantastic," the webdevs said. "Anything to avoid opening devtools."
Except, that's two bad technical decisions. The first is spending money on compute that they don't even need. The second is that compute now has to be JavaScript. What could be a highly efficient Rust or Go API server blasting out JSON at light speed is now stuck running JS and React. Somewhere, someone at Vercel looks at their quarterly earnings and smiles.
Seems like using a low tier android gives you a nice reality check.