Vite 8.1 and the end of the "unbundled dev server" dogma
Vite 8.1 adds experimental bundled dev mode. It sounds like a small switch, but for large apps it may be one of the more important dev experience changes in years.
For years, Vite won with a very simple idea: in development, we do not bundle the whole app, we serve modules directly to the browser. And for a long time, that was great. Startup was fast, HMR felt nice, and the whole DX felt much lighter than the classic webpack-style "wait until it grinds through everything".
The problem is that every architecture has its pain point. In really large applications, this kind of "unbundled" setup starts to mean hundreds, if not thousands, of requests, a huge overhead and cost on the browser side, proxies, cache, and all the things you can usually ignore only in smaller projects.
That is why in Vite 8.1, the interesting part is not only the release itself, but the direction: experimental bundledDev, previously known as Full Bundle Mode. In other words, an attempt to combine a production-style bundling approach with dev server ergonomics.
According to the Vite team, on a test application with 10,000 React components, startup was about 15x faster, full reloads were about 10x faster, and HMR stayed instant regardless of app size. Linear, in a real project, reported up to 3x faster cold start render, around 40% faster full reloads, and 10x fewer requests.
Of course, this is still an experiment. Some plugins may not work, some less popular Vite features may be missing, and the whole mode still needs to mature. But the fact that Vite is officially starting to address the scale of large frontends is, to me, more important than some not-so-positive benchmarks.
The "unbundled dev server" was a brilliant shortcut when the problem was a slow bundler. Now, with Rolldown and huge applications, the problem is increasingly not bundling itself, but the number of modules, requests, and browser overhead.
If you have a large frontend on Vite and you feel that your local environment is no longer as instant as it used to be, then vite --experimental-bundle looks like something worth at least checking on a branch.