TanStack Start (Built-in)

Overview

Selecting TanStack Start (built-in) as your backend means you're using TanStack Start's native server capabilities — createAPIFileRoute for HTTP endpoints and createServerFn for server functions. No separate server process is needed.

This is the idiomatic backend for TanStack Start projects: API logic lives alongside your routes in app/routes/api/, and server functions can be called directly from any component or route loader.

This option is only available when your frontend is TanStack Start. For a standalone Node.js API server alongside TanStack Start, choose Hono instead.

Scaffolded Structure

app/
  routes/
    api/
      health.ts       # GET /api/health — starter endpoint
  server/
    functions.ts      # Example server function via createServerFn

API Routes

API routes use createAPIFileRoute and live in app/routes/api/:

// app/routes/api/health.ts
import { createAPIFileRoute } from "@tanstack/start/api"

export const APIRoute = createAPIFileRoute("/api/health")({
  GET: () => Response.json({ status: "ok" }),
})

File-based routing applies here too — the file path determines the URL:

Server Functions

Server functions run exclusively on the server. Call them from any component, route loader, or server action — they are automatically serialized over the network:

// app/server/functions.ts
import { createServerFn } from "@tanstack/start"

export const getServerMessage = createServerFn().handler(async () => {
  // Safe to use DB connections, secrets, etc.
  return { message: "Hello from the server" }
})

// app/routes/index.tsx — call in a route loader
import { createFileRoute } from "@tanstack/react-router"
import { getServerMessage } from "@/app/server/functions"

export const Route = createFileRoute("/")({
  loader: () => getServerMessage(),
  component: () => {
    const data = Route.useLoaderData()
    return <p>{data.message}</p>
  },
})

Pairing with an API Layer

For end-to-end type safety, combine the built-in backend with tRPC or oRPC. Both mount their handlers via createAPIFileRoute:

See the tRPC and oRPC docs for setup details.

Compatibility

• ✅ Works with: Clerk, WorkOS, Better Auth, Resend, shadcn/ui, tRPC, oRPC, Drizzle, Prisma, Mongoose
• ❌ Convex DB is not available — Convex requires the Convex backend
• ❌ Cannot be combined with Next.js or Vite React frontends — this backend type is TanStack Start only