diff --git a/src/app/api/creatives/[id]/action/route.ts b/src/app/api/creatives/[id]/action/route.ts
new file mode 100644
index 0000000..45ba2c3
--- /dev/null
+++ b/src/app/api/creatives/[id]/action/route.ts
@@ -0,0 +1,77 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { createClient } from '@/lib/supabase/server';
+import { resolveActiveTenant } from '@/lib/tenant-context';
+import { userRole } from '@/lib/agency';
+import {
+  sendCreativeToClient,
+  approveCreative,
+  rejectCreative,
+  retireCreative,
+} from '@/lib/creatives-workflow';
+
+export async function POST(
+  req: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const supabase = await createClient();
+  const {
+    data: { user },
+  } = await supabase.auth.getUser();
+
+  if (!user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  const { id } = await params;
+  const ctx = await resolveActiveTenant(user);
+  const tenantId = ctx.tenantId;
+
+  if (!tenantId) {
+    return NextResponse.json(
+      { error: 'Tenant context required' },
+      { status: 400 }
+    );
+  }
+
+  let body: any;
+  try {
+    body = await req.json();
+  } catch {
+    return NextResponse.json({ error: 'Invalid JSON body' }, { status: 400 });
+  }
+
+  const action = body.action; // 'send_to_client' | 'approve' | 'reject' | 'retire'
+  const role = userRole(user);
+  const actor = { role, userId: user.id };
+
+  try {
+    let result: any;
+    switch (action) {
+      case 'send_to_client':
+        result = await sendCreativeToClient(id, tenantId, actor);
+        break;
+
+      case 'approve':
+        result = await approveCreative(id, tenantId, actor, body.comment);
+        break;
+
+      case 'reject':
+        result = await rejectCreative(id, tenantId, actor, body.comment);
+        break;
+
+      case 'retire':
+        result = await retireCreative(id, tenantId, actor, body.reason);
+        break;
+
+      default:
+        return NextResponse.json(
+          { error: `Acción desconocida: ${action}` },
+          { status: 400 }
+        );
+    }
+
+    return NextResponse.json({ ok: true, creative: result });
+  } catch (err: any) {
+    return NextResponse.json({ error: err.message }, { status: 400 });
+  }
+}
diff --git a/src/app/api/integrations/creatives/[id]/route.ts b/src/app/api/integrations/creatives/[id]/route.ts
new file mode 100644
index 0000000..00a2365
--- /dev/null
+++ b/src/app/api/integrations/creatives/[id]/route.ts
@@ -0,0 +1,82 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { authenticateIntegrationRequest } from '@/lib/integrations-auth';
+import { createClient } from '@supabase/supabase-js';
+
+export async function PATCH(
+  req: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  let body: any;
+  try {
+    body = await req.json();
+  } catch {
+    return NextResponse.json({ error: 'Invalid JSON body' }, { status: 400 });
+  }
+
+  const { id } = await params;
+  const auth = await authenticateIntegrationRequest(req, { requireTenant: true, parsedBody: body });
+  if (!auth.ok) {
+    return auth.errorResponse!;
+  }
+
+  const tenantId = auth.tenantId!;
+  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
+  const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY!;
+  const adminClient = createClient(supabaseUrl, serviceRoleKey);
+
+  // Obtener creatividad previa
+  const { data: creative, error: getErr } = await adminClient
+    .from('creatives')
+    .select('*')
+    .eq('id', id)
+    .eq('tenant_id', tenantId)
+    .maybeSingle();
+
+  if (getErr || !creative) {
+    return NextResponse.json({ error: 'Creatividad no encontrada' }, { status: 404 });
+  }
+
+  const prevStatus = creative.status;
+
+  const updates: Record<string, any> = {
+    updated_at: new Date().toISOString(),
+  };
+
+  if (body.meta_ad_id !== undefined) updates.meta_ad_id = body.meta_ad_id;
+  if (body.status !== undefined) updates.status = body.status;
+  if (body.adset_id !== undefined) updates.adset_id = body.adset_id;
+  if (body.campaign_name !== undefined) updates.campaign_name = body.campaign_name;
+  if (body.asset_url !== undefined) updates.asset_url = body.asset_url;
+  if (body.thumbnail_url !== undefined) updates.thumbnail_url = body.thumbnail_url;
+
+  const { data: updated, error: updateErr } = await adminClient
+    .from('creatives')
+    .update(updates)
+    .eq('id', id)
+    .eq('tenant_id', tenantId)
+    .select('*')
+    .single();
+
+  if (updateErr) {
+    return NextResponse.json({ error: updateErr.message }, { status: 500 });
+  }
+
+  // Si pasa a publicada o cambia meta_ad_id, registrar en creative_events
+  if (updates.status === 'publicada' || updates.meta_ad_id) {
+    await adminClient.from('creative_events').insert({
+      tenant_id: tenantId,
+      creative_id: id,
+      event_type: updates.status === 'publicada' ? 'published' : 'creative_updated',
+      actor: auth.caller || 'n8n',
+      from_status: prevStatus,
+      to_status: updates.status || prevStatus,
+      payload: {
+        meta_ad_id: updates.meta_ad_id || creative.meta_ad_id,
+        adset_id: updates.adset_id,
+      },
+      visibility: 'client',
+    });
+  }
+
+  return NextResponse.json(updated);
+}
diff --git a/src/lib/creatives-webhooks.test.ts b/src/lib/creatives-webhooks.test.ts
new file mode 100644
index 0000000..5f3e3d6
--- /dev/null
+++ b/src/lib/creatives-webhooks.test.ts
@@ -0,0 +1,79 @@
+import { describe, it } from 'node:test';
+import assert from 'node:assert';
+import http from 'node:http';
+import {
+  signWebhookPayload,
+  verifyWebhookSignature,
+  dispatchN8nWebhook,
+} from './creatives-webhooks';
+
+describe('Creatives Outbound Webhook & HMAC Signature', () => {
+  const secret = 'whsec_4v_test_secret_123456789';
+  const payload = JSON.stringify({
+    event: 'creative.approved',
+    timestamp: '2026-10-12T10:00:00.000Z',
+    data: {
+      client_id: '8bec977a-6032-4759-aa7f-b5042081f450',
+      creative_id: '1800fa1e-e969-469c-9913-6c973acba346',
+      approved_by_role: 'client',
+      comment: 'Aprobado para lanzar mañana.',
+    },
+  });
+
+  it('signs payload and verifies valid HMAC-SHA256 signature', () => {
+    const signature = signWebhookPayload(payload, secret);
+    assert.ok(signature && signature.length === 64, 'HMAC hex signature must be 64 characters');
+    const isValid = verifyWebhookSignature(payload, signature, secret);
+    assert.strictEqual(isValid, true, 'Signature must verify against same secret');
+  });
+
+  it('rejects tampered payload or incorrect secret', () => {
+    const signature = signWebhookPayload(payload, secret);
+    const tampered = payload.replace('lanzar mañana', 'no lanzar');
+    assert.strictEqual(verifyWebhookSignature(tampered, signature, secret), false);
+    assert.strictEqual(verifyWebhookSignature(payload, signature, 'wrong-secret'), false);
+  });
+
+  it('dispatches HTTP POST with X-Signature header to a test server and verifies signature', async () => {
+    let receivedHeader: string | null = null;
+    let receivedBody = '';
+
+    // Iniciar servidor HTTP local para verificar el webhook firmado
+    const server = http.createServer((req, res) => {
+      receivedHeader = req.headers['x-signature'] as string;
+      req.on('data', (chunk) => {
+        receivedBody += chunk;
+      });
+      req.on('end', () => {
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ ok: true }));
+      });
+    });
+
+    await new Promise<void>((resolve) => server.listen(0, '127.0.0.1', () => resolve()));
+    const port = (server.address() as any).port;
+    const testUrl = `http://127.0.0.1:${port}/webhook`;
+
+    process.env.N8N_WEBHOOK_BASE = testUrl;
+    process.env.N8N_WEBHOOK_SECRET = secret;
+
+    try {
+      const result = await dispatchN8nWebhook('creative.approved', {
+        client_id: '8bec977a-6032-4759-aa7f-b5042081f450',
+        creative_id: '1800fa1e-e969-469c-9913-6c973acba346',
+        approved_by_role: 'agency',
+        comment: 'Validado por la agencia',
+      });
+
+      assert.strictEqual(result.sent, true);
+      assert.strictEqual(result.status, 200);
+      assert.ok(receivedHeader, 'X-Signature header must be received');
+
+      // Comprobar la firma recibida en el servidor con el body recibido y el secreto
+      const verified = verifyWebhookSignature(receivedBody, receivedHeader!, secret);
+      assert.strictEqual(verified, true, 'Server must verify HMAC signature with shared secret');
+    } finally {
+      server.close();
+    }
+  });
+});
diff --git a/src/lib/creatives-webhooks.ts b/src/lib/creatives-webhooks.ts
new file mode 100644
index 0000000..79e908c
--- /dev/null
+++ b/src/lib/creatives-webhooks.ts
@@ -0,0 +1,84 @@
+import crypto from 'node:crypto';
+
+export type CreativeWebhookEvent =
+  | 'creative.approved'
+  | 'creative.rejected'
+  | 'creative.sent_to_client';
+
+export interface WebhookDispatchResult {
+  sent: boolean;
+  url?: string;
+  signature?: string;
+  status?: number;
+  error?: string;
+}
+
+/**
+ * Calcula la firma HMAC-SHA256 para el payload del webhook
+ */
+export function signWebhookPayload(payloadStr: string, secret: string): string {
+  return crypto.createHmac('sha256', secret).update(payloadStr).digest('hex');
+}
+
+/**
+ * Verifica una firma HMAC-SHA256
+ */
+export function verifyWebhookSignature(payloadStr: string, signature: string, secret: string): boolean {
+  try {
+    const expected = signWebhookPayload(payloadStr, secret);
+    return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Envía un webhook firmado hacia n8n (N8N_WEBHOOK_BASE/event)
+ */
+export async function dispatchN8nWebhook(
+  event: CreativeWebhookEvent,
+  payload: Record<string, unknown>
+): Promise<WebhookDispatchResult> {
+  const baseUrl = process.env.N8N_WEBHOOK_BASE?.trim() || 'https://n8n-agencia.4ventures.es/webhook';
+  const secret = process.env.N8N_WEBHOOK_SECRET?.trim() || 'whsec_4v_7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d';
+
+  if (!baseUrl) {
+    return { sent: false, error: 'N8N_WEBHOOK_BASE is not configured' };
+  }
+
+  const endpoint = `${baseUrl.replace(/\/$/, '')}/${event.replace('.', '-')}`;
+  const fullBody = {
+    event,
+    timestamp: new Date().toISOString(),
+    data: payload,
+  };
+
+  const bodyStr = JSON.stringify(fullBody);
+  const signature = signWebhookPayload(bodyStr, secret);
+
+  try {
+    const res = await fetch(endpoint, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'X-Signature': signature,
+        'User-Agent': '4Ventures-App-Webhook/1.0',
+      },
+      body: bodyStr,
+    });
+
+    return {
+      sent: true,
+      url: endpoint,
+      signature,
+      status: res.status,
+    };
+  } catch (err: any) {
+    return {
+      sent: false,
+      url: endpoint,
+      signature,
+      error: err.message,
+    };
+  }
+}
diff --git a/src/lib/creatives-workflow.ts b/src/lib/creatives-workflow.ts
new file mode 100644
index 0000000..6c110cc
--- /dev/null
+++ b/src/lib/creatives-workflow.ts
@@ -0,0 +1,286 @@
+import { createClient } from '@supabase/supabase-js';
+import { dispatchN8nWebhook } from './creatives-webhooks';
+import { normalizeRole } from './creatives-visibility';
+
+export interface ActionActor {
+  role: 'agency' | 'client' | string;
+  userId?: string | null;
+}
+
+function getAdminClient() {
+  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
+  const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY!;
+  return createClient(supabaseUrl, serviceRoleKey);
+}
+
+/**
+ * 1. Enviar al cliente
+ * Cambia visibility a 'client' y status a 'pendiente_aprobacion'
+ * Dispara webhook 'creative.sent_to_client'
+ */
+export async function sendCreativeToClient(creativeId: string, tenantId: string, actor: ActionActor) {
+  const adminClient = getAdminClient();
+
+  const { data: creative, error: getErr } = await adminClient
+    .from('creatives')
+    .select('*')
+    .eq('id', creativeId)
+    .eq('tenant_id', tenantId)
+    .single();
+
+  if (getErr || !creative) {
+    throw new Error('Creatividad no encontrada');
+  }
+
+  const prevStatus = creative.status;
+
+  const { data: updated, error: updateErr } = await adminClient
+    .from('creatives')
+    .update({
+      visibility: 'client',
+      status: 'pendiente_aprobacion',
+      updated_at: new Date().toISOString(),
+    })
+    .eq('id', creativeId)
+    .select('*')
+    .single();
+
+  if (updateErr) {
+    throw new Error(updateErr.message);
+  }
+
+  // Registrar en creative_events
+  await adminClient.from('creative_events').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    event_type: 'status_change',
+    actor: actor.userId ? `user:${actor.userId}` : 'agency',
+    from_status: prevStatus,
+    to_status: 'pendiente_aprobacion',
+    payload: { action: 'sent_to_client' },
+    visibility: 'client',
+  });
+
+  // Disparar webhook saliente a n8n
+  await dispatchN8nWebhook('creative.sent_to_client', {
+    client_id: tenantId,
+    tenant_id: tenantId,
+    creative_id: creativeId,
+  });
+
+  return updated;
+}
+
+/**
+ * 2. Aprobar creatividad
+ * Cambia status a 'aprobada'
+ * Escribe en approvals y creative_events
+ * Dispara webhook 'creative.approved'
+ */
+export async function approveCreative(
+  creativeId: string,
+  tenantId: string,
+  actor: ActionActor,
+  comment?: string | null
+) {
+  const adminClient = getAdminClient();
+  const normRole = normalizeRole(actor.role);
+
+  const { data: creative, error: getErr } = await adminClient
+    .from('creatives')
+    .select('*')
+    .eq('id', creativeId)
+    .eq('tenant_id', tenantId)
+    .single();
+
+  if (getErr || !creative) {
+    throw new Error('Creatividad no encontrada');
+  }
+
+  const prevStatus = creative.status;
+
+  const { data: updated, error: updateErr } = await adminClient
+    .from('creatives')
+    .update({
+      status: 'aprobada',
+      updated_at: new Date().toISOString(),
+    })
+    .eq('id', creativeId)
+    .select('*')
+    .single();
+
+  if (updateErr) {
+    throw new Error(updateErr.message);
+  }
+
+  // Registrar en approvals
+  await adminClient.from('approvals').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    user_id: actor.userId || null,
+    actor_role: normRole,
+    decision: 'aprobada',
+    comment: comment || null,
+    channel: 'app',
+  });
+
+  // Registrar en creative_events
+  await adminClient.from('creative_events').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    event_type: 'status_change',
+    actor: actor.userId ? `user:${actor.userId}` : normRole,
+    from_status: prevStatus,
+    to_status: 'aprobada',
+    payload: { comment },
+    visibility: 'client',
+  });
+
+  // Disparar webhook saliente a n8n
+  await dispatchN8nWebhook('creative.approved', {
+    client_id: tenantId,
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    approved_by_role: normRole,
+    comment: comment || null,
+  });
+
+  return updated;
+}
+
+/**
+ * 3. Rechazar creatividad
+ * Comentario obligatorio
+ * Cambia status a 'rechazada'
+ * Escribe en approvals y creative_events
+ * Dispara webhook 'creative.rejected'
+ */
+export async function rejectCreative(
+  creativeId: string,
+  tenantId: string,
+  actor: ActionActor,
+  comment: string
+) {
+  if (!comment || !comment.trim()) {
+    throw new Error('El comentario es obligatorio al rechazar una creatividad');
+  }
+
+  const adminClient = getAdminClient();
+  const normRole = normalizeRole(actor.role);
+
+  const { data: creative, error: getErr } = await adminClient
+    .from('creatives')
+    .select('*')
+    .eq('id', creativeId)
+    .eq('tenant_id', tenantId)
+    .single();
+
+  if (getErr || !creative) {
+    throw new Error('Creatividad no encontrada');
+  }
+
+  const prevStatus = creative.status;
+
+  const { data: updated, error: updateErr } = await adminClient
+    .from('creatives')
+    .update({
+      status: 'rechazada',
+      updated_at: new Date().toISOString(),
+    })
+    .eq('id', creativeId)
+    .select('*')
+    .single();
+
+  if (updateErr) {
+    throw new Error(updateErr.message);
+  }
+
+  // Registrar en approvals
+  await adminClient.from('approvals').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    user_id: actor.userId || null,
+    actor_role: normRole,
+    decision: 'rechazada',
+    comment: comment.trim(),
+    channel: 'app',
+  });
+
+  // Registrar en creative_events
+  await adminClient.from('creative_events').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    event_type: 'status_change',
+    actor: actor.userId ? `user:${actor.userId}` : normRole,
+    from_status: prevStatus,
+    to_status: 'rechazada',
+    payload: { comment: comment.trim() },
+    visibility: 'agency',
+  });
+
+  // Disparar webhook saliente a n8n
+  await dispatchN8nWebhook('creative.rejected', {
+    client_id: tenantId,
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    rejected_by_role: normRole,
+    comment: comment.trim(),
+  });
+
+  return updated;
+}
+
+/**
+ * 4. Retirar creatividad
+ * Cambia status a 'retirada'
+ */
+export async function retireCreative(
+  creativeId: string,
+  tenantId: string,
+  actor: ActionActor,
+  reason?: string
+) {
+  const adminClient = getAdminClient();
+  const normRole = normalizeRole(actor.role);
+
+  const { data: creative, error: getErr } = await adminClient
+    .from('creatives')
+    .select('*')
+    .eq('id', creativeId)
+    .eq('tenant_id', tenantId)
+    .single();
+
+  if (getErr || !creative) {
+    throw new Error('Creatividad no encontrada');
+  }
+
+  const prevStatus = creative.status;
+
+  const { data: updated, error: updateErr } = await adminClient
+    .from('creatives')
+    .update({
+      status: 'retirada',
+      updated_at: new Date().toISOString(),
+    })
+    .eq('id', creativeId)
+    .select('*')
+    .single();
+
+  if (updateErr) {
+    throw new Error(updateErr.message);
+  }
+
+  // Registrar en creative_events
+  await adminClient.from('creative_events').insert({
+    tenant_id: tenantId,
+    creative_id: creativeId,
+    event_type: 'status_change',
+    actor: actor.userId ? `user:${actor.userId}` : normRole,
+    from_status: prevStatus,
+    to_status: 'retirada',
+    payload: { reason: reason || null },
+    visibility: 'client',
+  });
+
+  return updated;
+}