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#ReactDomServerProvider

#Import

typescript 
1import { ReactDomServerProvider } from "alepha/react/router";

#Overview

The renderer half of React, loaded only once something actually renders.

react-dom/server is ~196KB minified — on workerd that is ~12% of the bytes parsed before a handler runs, and it was being parsed on every cold start regardless of what the request wanted. Most invocations of a typical Alepha app render no HTML at all: they answer an API route, a webhook or a telemetry POST. Those paid for the renderer and never called it.

Loading it through this provider keeps it out of the eager module graph, so it becomes an async chunk the runtime fetches on the first render and never again. react itself (~8KB) stays eagerly imported, which is what it should be — every component module needs jsx and the hooks.

⚠️ A static import … from "react-dom/server" anywhere in the server graph undoes this completely. One eager edge pulls the whole module back onto the cold-start path and nothing about this provider will report that it happened. REACT_SSR_ENABLED=false does not help either: it is read at runtime, long after the module graph has been decided.