Router at the core
The framework does not replace the application model.
Routes, params, search schemas, loaders, links, pending states, and boundaries stay TanStack Router. Start adds the server and build layers around that same tree.
Start server layer
SSR · streaming · server functions · routes · middleware
TanStack Router
route tree · URL state · loaders · links · boundaries
Your application
components · data clients · product behavior
Explicit boundaries
Server work is visible in the code that calls it.
Use server functions for type-safe app calls, server routes for outside callers, and composable middleware for authentication, context, logging, and policy.
Portable application model
Keep the routes. Change the output.
Start supports Vite and Rsbuild and is designed for different hosting providers and runtimes. Deployment configuration changes; route authoring and server boundaries do not.