Outsider question: why use Rollup when Esbuild exist? Is esbuild not enough for production builds?

it is not. lack of plugin support is sufficient to block adoptions among other things.

but it has plugin support? what kind of plugins you mean?

	▲	rk06 13 minutes ago \| parent [-]
		look at plugin api limiation here: https://esbuild.github.io/plugins/#svelte-plugin esbuild's plugin support is limited which is why vite had to use rollup for prod build.