Not signed in
returnHello {userId}
} ``` > **Core 2 ONLY (skip if current SDK):** `isAuthenticated` is not available. Use `if (!userId)` instead. ### Conditional Rendering with `Not authenticated
const res = await fetch('https://api.example.com/graphql', { headers: { Authorization: `Bearer ${token}` }, }) const data = await res.json() return{JSON.stringify(data)}
}
```
**Client-side (Client Component)**:
```typescript
'use client'
import { useAuth } from '@clerk/nextjs'
export function DataFetcher() {
const { getToken } = useAuth()
async function fetchData() {
const token = await getToken({ template: 'supabase' })
if (!token) return
const res = await fetch('https://api.example.com/data', {
headers: { Authorization: `Bearer ${token}` },
})
return res.json()
}
return
}
```
`getToken()` returns `null` when the user is not authenticated — always null-check before use.
### useSession() for session data
Access session metadata in client components:
```typescript
'use client'
import { useSession } from '@clerk/nextjs'
export function SessionInfo() {
const { session } = useSession()
if (!session) return null
return (
Session {session.id} — last active: {session.lastActiveAt.toISOString()}
) } ``` ### Manual JWT verification (no Clerk middleware) For standalone API servers that receive Clerk session tokens from the `Authorization` header or the `__session` cookie (same-origin). **Using `@clerk/backend` `verifyToken`** (recommended): ```typescript import { verifyToken } from '@clerk/backend' const token = req.headers.authorization?.replace('Bearer ', '') if (!token) return res.status(401).json({ error: 'No token' }) try { const claims = await verifyToken(token, { jwtKey: process.env.CLERK_JWT_KEY, }) // claims.sub = userId } catch { return res.status(401).json({ error: 'Invalid token' }) } ``` **Using `jsonwebtoken`** (when you can't use `@clerk/backend`): ```typescript import jwt from 'jsonwebtoken' const publicKey = process.env.CLERK_PEM_PUBLIC_KEY!.replace(/\\n/g, '\n') const token = req.headers.authorization?.replace('Bearer ', '') if (!token) return res.status(401).json({ error: 'No token' }) try { const claims = jwt.verify(token, publicKey, { algorithms: ['RS256'] }) as jwt.JwtPayload // Manually check exp and nbf (jsonwebtoken does this automatically, but verify azp if needed) // claims.sub = userId } catch { return res.status(401).json({ error: 'Invalid or expired token' }) } ``` Token sources: - **Same-origin requests**: `__session` cookie (Clerk sets this automatically) - **Cross-origin / mobile / API-to-API**: `Authorization: Bearer