clerk-tanstack-patterns
TanStack React Start auth patterns with @clerk/tanstack-react-start - createServerFn, beforeLoad guards, loaders, Vinxi server. Triggers on: TanStack auth, createServerFn clerk, beforeLoad protection, TanStack Start middleware.
What this skill does
# TanStack React Start Patterns
## What Do You Need?
| Task | Reference |
|------|-----------|
| Protect routes with beforeLoad | references/router-guards.md |
| Auth in createServerFn | references/server-functions.md |
| Pass auth to loaders | references/loaders.md |
| Configure Vinxi + clerkMiddleware | references/vinxi-server.md |
## References
| Reference | Description |
|-----------|-------------|
| `references/router-guards.md` | beforeLoad auth redirect |
| `references/server-functions.md` | createServerFn with auth() |
| `references/loaders.md` | Auth context in loaders |
| `references/vinxi-server.md` | clerkMiddleware() setup |
## Setup
```
npm install @clerk/tanstack-react-start
```
`.env`:
```
CLERK_PUBLISHABLE_KEY=pk_...
CLERK_SECRET_KEY=sk_...
```
`src/start.ts` (Vinxi entry):
```typescript
import { clerkMiddleware } from '@clerk/tanstack-react-start/server'
import { createStart } from '@tanstack/react-start'
export const startInstance = createStart(() => {
return {
requestMiddleware: [clerkMiddleware()],
}
})
```
`src/routes/__root.tsx` — wrap with `<ClerkProvider>`:
```tsx
import { ClerkProvider } from '@clerk/tanstack-react-start'
function RootDocument({ children }: { children: React.ReactNode }) {
return (
<html lang="en">
<body>
<ClerkProvider>
{children}
</ClerkProvider>
</body>
</html>
)
}
```
## Mental Model
TanStack Start runs on Vinxi. Auth flows through two layers:
1. **Server layer** — `createServerFn` + `auth()` from `@clerk/tanstack-react-start/server`
2. **Router layer** — `beforeLoad` on route definitions, throws `redirect` for unauthenticated
Both layers are server-executed. Client hooks (`useAuth`, `useUser`) are React hooks for the browser side.
## Minimal Pattern
```typescript
import { createFileRoute, redirect } from '@tanstack/react-router'
import { createServerFn } from '@tanstack/react-start'
import { auth } from '@clerk/tanstack-react-start/server'
const authStateFn = createServerFn().handler(async () => {
const { isAuthenticated, userId } = await auth()
if (!isAuthenticated) {
throw redirect({ to: '/sign-in' })
}
return { userId }
})
export const Route = createFileRoute('/dashboard')({
beforeLoad: async () => await authStateFn(),
})
```
## Common Pitfalls
| Symptom | Cause | Fix |
|---------|-------|-----|
| `auth()` returns empty | Missing `clerkMiddleware` in start.ts | Add to `requestMiddleware` array |
| `redirect` not thrown | Using `return` instead of `throw` | `throw redirect(...)` in TanStack |
| Wrong import for `auth` | Mixing client/server imports | Server: `@clerk/tanstack-react-start/server` |
| Loader context missing userId | Not passing from beforeLoad | Return from beforeLoad, access via `context` |
| `ClerkProvider` missing | Forgot root wrapping | Add to `__root.tsx` shell component |
## See Also
- `clerk-setup` - Initial Clerk install
- `clerk-custom-ui` - Custom flows & appearance
- `clerk-orgs` - B2B organizations
## Docs
[TanStack React Start SDK](https://clerk.com/docs/tanstack-react-start/getting-started/quickstart)
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