diff --git a/.env.example b/.env.example
index 1cac979..ab61549 100644
--- a/.env.example
+++ b/.env.example
@@ -8,3 +8,9 @@ SESSION_SECRET="replace-with-at-least-32-characters"
 
 # Optional; Vercel and Node set this automatically in deployed environments.
 NODE_ENV="development"
+
+# M11 (ST-1107) — shared secret between Vercel cron-trigger and the
+# /api/cron/expire-questions handler. Required in production; optional in
+# local dev (the route returns 401 if the Authorization header doesn't match).
+# Generate with: openssl rand -base64 32
+CRON_SECRET=""
diff --git a/__tests__/api/cron-expire-questions.test.ts b/__tests__/api/cron-expire-questions.test.ts
new file mode 100644
index 0000000..d539d8b
--- /dev/null
+++ b/__tests__/api/cron-expire-questions.test.ts
@@ -0,0 +1,77 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+vi.mock('@/lib/prisma', () => ({
+  prisma: {
+    claudeQuestion: { updateMany: vi.fn() },
+    loginPairing: { updateMany: vi.fn() },
+  },
+}))
+
+import { prisma } from '@/lib/prisma'
+import { POST } from '@/app/api/cron/expire-questions/route'
+
+const mockPrisma = prisma as unknown as {
+  claudeQuestion: { updateMany: ReturnType<typeof vi.fn> }
+  loginPairing: { updateMany: ReturnType<typeof vi.fn> }
+}
+
+const SECRET = 'test-cron-secret-abc123'
+
+function makeReq(headers: Record<string, string> = {}): Request {
+  return new Request('http://localhost:3000/api/cron/expire-questions', {
+    method: 'POST',
+    headers,
+  })
+}
+
+beforeEach(() => {
+  vi.clearAllMocks()
+  process.env.CRON_SECRET = SECRET
+  mockPrisma.claudeQuestion.updateMany.mockResolvedValue({ count: 0 })
+  mockPrisma.loginPairing.updateMany.mockResolvedValue({ count: 0 })
+})
+
+describe('POST /api/cron/expire-questions', () => {
+  it('401 zonder Authorization-header', async () => {
+    const res = await POST(makeReq())
+    expect(res.status).toBe(401)
+    expect(mockPrisma.claudeQuestion.updateMany).not.toHaveBeenCalled()
+    expect(mockPrisma.loginPairing.updateMany).not.toHaveBeenCalled()
+  })
+
+  it('401 met verkeerde secret', async () => {
+    const res = await POST(makeReq({ authorization: 'Bearer wrong-secret' }))
+    expect(res.status).toBe(401)
+  })
+
+  it('401 als CRON_SECRET niet is gezet (faal-veilig)', async () => {
+    delete process.env.CRON_SECRET
+    const res = await POST(makeReq({ authorization: 'Bearer ' + SECRET }))
+    expect(res.status).toBe(401)
+  })
+
+  it('200 met juiste secret + beide updateMany aangeroepen', async () => {
+    mockPrisma.claudeQuestion.updateMany.mockResolvedValue({ count: 3 })
+    mockPrisma.loginPairing.updateMany.mockResolvedValue({ count: 1 })
+
+    const res = await POST(makeReq({ authorization: 'Bearer ' + SECRET }))
+    expect(res.status).toBe(200)
+    const body = await res.json()
+    expect(body).toMatchObject({
+      expired_questions: 3,
+      expired_pairings: 1,
+    })
+    expect(body.ran_at).toMatch(/^\d{4}-\d{2}-\d{2}T/)
+
+    // Question-update: status='open' AND expires_at < now → 'expired'
+    const qArg = mockPrisma.claudeQuestion.updateMany.mock.calls[0][0]
+    expect(qArg.where).toMatchObject({ status: 'open' })
+    expect(qArg.where.expires_at).toMatchObject({ lt: expect.any(Date) })
+    expect(qArg.data).toEqual({ status: 'expired' })
+
+    // Pairing-update: status='pending' AND expires_at < now → 'cancelled'
+    const pArg = mockPrisma.loginPairing.updateMany.mock.calls[0][0]
+    expect(pArg.where).toMatchObject({ status: 'pending' })
+    expect(pArg.data).toEqual({ status: 'cancelled' })
+  })
+})
diff --git a/app/api/cron/expire-questions/route.ts b/app/api/cron/expire-questions/route.ts
new file mode 100644
index 0000000..ba72bd1
--- /dev/null
+++ b/app/api/cron/expire-questions/route.ts
@@ -0,0 +1,44 @@
+// ST-1107: Vercel cron handler die verlopen Claude-vragen op 'expired' zet.
+//
+// Wordt elke 6 uur door Vercel POST'd (zie vercel.ts crons-config). Auth is
+// via een gedeeld secret in de Authorization-header — Vercel injecteert
+// `Authorization: Bearer <CRON_SECRET>` automatisch wanneer de env-var op de
+// project-omgeving staat.
+//
+// Bonus (ST-1107.4): zelfde route ruimt ook M10's verlopen `pending`
+// login_pairings op. Reden: één cron-job is goedkoper qua Vercel-budget en
+// houdt de cleanup-strategie centraal.
+
+import { prisma } from '@/lib/prisma'
+
+export const runtime = 'nodejs'
+
+export async function POST(request: Request) {
+  const auth = request.headers.get('authorization')
+  const expected = process.env.CRON_SECRET
+  if (!expected || auth !== `Bearer ${expected}`) {
+    return Response.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const now = new Date()
+
+  // M11: open Claude-vragen → expired
+  const expiredQuestions = await prisma.claudeQuestion.updateMany({
+    where: { status: 'open', expires_at: { lt: now } },
+    data: { status: 'expired' },
+  })
+
+  // M10: pending login_pairings die niet meer bruikbaar zijn → cancelled
+  // (status='expired' bestaat niet voor pairings; cancelled heeft hetzelfde
+  // resultaat: niet-claimable, niet meer in de SSE-listener.)
+  const expiredPairings = await prisma.loginPairing.updateMany({
+    where: { status: 'pending', expires_at: { lt: now } },
+    data: { status: 'cancelled' },
+  })
+
+  return Response.json({
+    expired_questions: expiredQuestions.count,
+    expired_pairings: expiredPairings.count,
+    ran_at: now.toISOString(),
+  })
+}
diff --git a/lib/env.ts b/lib/env.ts
index 32d1650..40d0676 100644
--- a/lib/env.ts
+++ b/lib/env.ts
@@ -5,6 +5,10 @@ const envSchema = z.object({
   DIRECT_URL: z.string().optional(),
   SESSION_SECRET: z.string().min(32, 'SESSION_SECRET must be at least 32 characters'),
   NODE_ENV: z.enum(['development', 'production', 'test']).default('development'),
+  // M11 (ST-1107) — gedeeld geheim tussen Vercel cron-trigger en
+  // /api/cron/expire-questions. In productie verplicht; lokaal dev mag missen
+  // (de cron-route geeft 401 als de header niet matcht).
+  CRON_SECRET: z.string().optional(),
 })
 
 const parsed = envSchema.safeParse(process.env)
diff --git a/vercel.json b/vercel.json
new file mode 100644
index 0000000..e41e82c
--- /dev/null
+++ b/vercel.json
@@ -0,0 +1,9 @@
+{
+  "$schema": "https://openapi.vercel.sh/vercel.json",
+  "crons": [
+    {
+      "path": "/api/cron/expire-questions",
+      "schedule": "0 */6 * * *"
+    }
+  ]
+}