Clerk React Router Patterns

---
name: clerk-react-router-patterns
description: 'React Router v7 patterns with Clerk — rootAuthLoader, getAuth in loaders,
  clerkMiddleware, protected routes, SSR user data, org switching. Triggers on: react-router
  auth, rootAuthLoader, getAuth loader, react-router protected route, loader authentication,
  SSR auth react-router.'
license: MIT
allowed-tools: WebFetch
metadata:
  author: clerk
  version: 1.0.0
---

# React Router Patterns

SDK: `@clerk/react-router` v3+. Requires React Router v7.9+.

## What Do You Need?

| Task | Reference |
|------|-----------|
| Auth in loaders and actions | references/loaders-actions.md |
| Protected routes and redirects | references/protected-routes.md |
| SSR user data and session | references/ssr-auth.md |

## Mental Model

React Router v7 uses a middleware + loader pipeline. Clerk plugs into both layers:

- **Middleware** (`clerkMiddleware()`) — runs on every request, attaches auth to context
- **`rootAuthLoader`** — required in `root.tsx` to pass Clerk state to the client
- **`getAuth(args)`** — called inside any loader/action to get the current user

```
Request → clerkMiddleware() → rootAuthLoader → page loader → component
                 ↓                   ↓               ↓
           attaches auth      injects state     getAuth(args)
           to context         to response       reads context
```

## Minimal Setup

### 1. root.tsx

```tsx
import { rootAuthLoader } from '@clerk/react-router/server'
import { ClerkApp } from '@clerk/react-router'
import type { Route } from './+types/root'

export async function loader(args: Route.LoaderArgs) {
  return rootAuthLoader(args)
}

export default ClerkApp(function App() {
  return <Outlet />
})
```

### 2. Middleware (root route or entry.server.ts)

```tsx
import { clerkMiddleware } from '@clerk/react-router/server'
export const middleware = [clerkMiddleware()]
```

> **Required**: `rootAuthLoader` must be called in `root.tsx`'s loader. Without it, `getAuth` throws in nested loaders.

## Auth in Loaders

```tsx
import { getAuth } from '@clerk/react-router/server'
import type { Route } from './+types/dashboard'

export async function loader(args: Route.LoaderArgs) {
  const { userId } = await getAuth(args)
  if (!userId) throw redirect('/sign-in')

  const data = await fetchUserData(userId)
  return { data }
}
```

## Auth in Actions

```tsx
import { getAuth } from '@clerk/react-router/server'

export async function action(args: Route.ActionArgs) {
  const { userId, orgId } = await getAuth(args)
  if (!userId) throw new Response('Unauthorized', { status: 401 })

  const formData = await args.request.formData()
  await saveData(userId, orgId, formData)
  return redirect('/dashboard')
}
```

## Client Components

```tsx
import { useAuth, useUser } from '@clerk/react-router'

export function Profile() {
  const { userId, isSignedIn } = useAuth()
  const { user } = useUser()
  if (!isSignedIn) return null
  return <p>{user?.firstName}</p>
}
```

## Org Switching

```tsx
import { OrganizationSwitcher } from '@clerk/react-router'

export function Nav() {
  return <OrganizationSwitcher afterSelectOrganizationUrl="/dashboard" />
}
```

```tsx
export async function loader(args: Route.LoaderArgs) {
  const { userId, orgId } = await getAuth(args)
  if (!userId) throw redirect('/sign-in')
  if (!orgId) throw redirect('/select-org')

  return { data: await fetchOrgData(orgId) }
}
```

## Common Pitfalls

| Symptom | Cause | Fix |
|---------|-------|-----|
| `clerkMiddleware() not detected` | Missing middleware | Export `middleware = [clerkMiddleware()]` from root route |
| `getAuth` returns empty userId | `rootAuthLoader` not called | Call `rootAuthLoader(args)` in `root.tsx` loader |
| Infinite redirect loop | Redirect target is also protected | Exclude `/sign-in` from protection check |
| `redirect` not working in action | Using `Response` instead of `throw redirect()` | Use `throw redirect('/path')` from `react-router` |

## Import Map

| What | Import From |
|------|-------------|
| `getAuth` | `@clerk/react-router/server` |
| `rootAuthLoader` | `@clerk/react-router/server` |
| `clerkMiddleware` | `@clerk/react-router/server` |
| `ClerkApp` | `@clerk/react-router` |
| `useAuth`, `useUser` | `@clerk/react-router` |
| `OrganizationSwitcher` | `@clerk/react-router` |

## See Also

- `clerk-setup` - Initial Clerk install
- `clerk-custom-ui` - Custom flows & appearance
- `clerk-orgs` - B2B organizations

## Docs

[React Router SDK](https://clerk.com/docs/react-router/getting-started/quickstart)