ssr

Create a shared createRouter factory, then build a server entry using createRequestHandler with defaultRenderHandler or defaultStreamHandler, and a client entry that calls hydrateRoot with RouterClient. Loader data is automatically dehydrated on the server and hydrated on the client.

Non-streaming SSR renders the full page on the server and sends one HTML response via renderRouterToString. Streaming SSR uses renderRouterToStream to send the critical first paint immediately and stream remaining content, including deferred loader data, incrementally.

Yes, with SSR enabled loaders run on both client and server; they are not server-only like Remix or Next.js loaders. Browser-only APIs such as window or localStorage must be guarded with an environment check to avoid server crashes.

Yes, createRequestHandler accepts a Web API Request and returns a Web API Response, so Express handlers must convert req into a Request and pipe the response body back with node stream pipeline. An example conversion is included in the documentation.

Common causes include using hash fragments for conditional rendering, since hashes never reach the server, and browser-only APIs in loaders. Use search params for server-visible state and suppressHydrationWarning when pre-hydration scripts modify the DOM.

TanStack Start is the recommended way to do SSR in production because the manual SSR APIs are experimental and may change. Use manual SSR setup only when integrating TanStack Router with an existing server.