diff --git a/apps/api/src/controllers/tenants.controller.ts b/apps/api/src/controllers/tenants.controller.ts
index e7477ff..c1cdcc2 100644
--- a/apps/api/src/controllers/tenants.controller.ts
+++ b/apps/api/src/controllers/tenants.controller.ts
@@ -39,21 +39,24 @@ export async function createTenant(req: Request, res: Response, next: NextFuncti
       throw new AppError(403, 'Solo administradores pueden crear clientes');
     }
 
-    const { nombre, rfc, plan, cfdiLimit, usersLimit } = req.body;
+    const { nombre, rfc, plan, cfdiLimit, usersLimit, adminEmail, adminNombre, amount } = req.body;
 
-    if (!nombre || !rfc) {
-      throw new AppError(400, 'Nombre y RFC son requeridos');
+    if (!nombre || !rfc || !adminEmail || !adminNombre) {
+      throw new AppError(400, 'Nombre, RFC, adminEmail y adminNombre son requeridos');
     }
 
-    const tenant = await tenantsService.createTenant({
+    const result = await tenantsService.createTenant({
       nombre,
       rfc,
       plan,
       cfdiLimit,
       usersLimit,
+      adminEmail,
+      adminNombre,
+      amount: amount || 0,
     });
 
-    res.status(201).json(tenant);
+    res.status(201).json(result);
   } catch (error) {
     next(error);
   }
diff --git a/apps/api/src/services/fiel.service.ts b/apps/api/src/services/fiel.service.ts
index 7fbd0d7..2639836 100644
--- a/apps/api/src/services/fiel.service.ts
+++ b/apps/api/src/services/fiel.service.ts
@@ -4,6 +4,7 @@ import { join } from 'path';
 import { prisma } from '../config/database.js';
 import { env } from '../config/env.js';
 import { encryptFielCredentials, encrypt, decryptFielCredentials } from './sat/sat-crypto.service.js';
+import { emailService } from './email/email.service.js';
 import type { FielStatus } from '@horux/shared';
 
 /**
@@ -144,10 +145,22 @@ export async function uploadFiel(
       console.error('[FIEL] Filesystem storage failed (DB storage OK):', fsError);
     }
 
+    // Notify admin that client uploaded FIEL
+    const tenant = await prisma.tenant.findUnique({
+      where: { id: tenantId },
+      select: { nombre: true, rfc: true },
+    });
+    if (tenant) {
+      emailService.sendFielNotification({
+        clienteNombre: tenant.nombre,
+        clienteRfc: tenant.rfc,
+      }).catch(err => console.error('[EMAIL] FIEL notification failed:', err));
+    }
+
     const daysUntilExpiration = Math.ceil(
       (validUntil.getTime() - Date.now()) / (1000 * 60 * 60 * 24)
     );
-    
+
     return {
       success: true,
       message: 'FIEL configurada correctamente',
diff --git a/apps/api/src/services/tenants.service.ts b/apps/api/src/services/tenants.service.ts
index 9178ea9..1bbf725 100644
--- a/apps/api/src/services/tenants.service.ts
+++ b/apps/api/src/services/tenants.service.ts
@@ -1,5 +1,8 @@
 import { prisma, tenantDb } from '../config/database.js';
 import { PLANS } from '@horux/shared';
+import { emailService } from './email/email.service.js';
+import { randomBytes } from 'crypto';
+import bcrypt from 'bcryptjs';
 
 export async function getAllTenants() {
   return prisma.tenant.findMany({
@@ -41,13 +44,17 @@ export async function createTenant(data: {
   plan?: 'starter' | 'business' | 'professional' | 'enterprise';
   cfdiLimit?: number;
   usersLimit?: number;
+  adminEmail: string;
+  adminNombre: string;
+  amount: number;
 }) {
   const plan = data.plan || 'starter';
   const planConfig = PLANS[plan];
 
-  // Provision a dedicated database for this tenant
+  // 1. Provision a dedicated database for this tenant
   const databaseName = await tenantDb.provisionDatabase(data.rfc);
 
+  // 2. Create tenant record
   const tenant = await prisma.tenant.create({
     data: {
       nombre: data.nombre,
@@ -59,7 +66,39 @@ export async function createTenant(data: {
     }
   });
 
-  return tenant;
+  // 3. Create admin user with temp password
+  const tempPassword = randomBytes(4).toString('hex'); // 8-char random
+  const hashedPassword = await bcrypt.hash(tempPassword, 10);
+
+  const user = await prisma.user.create({
+    data: {
+      tenantId: tenant.id,
+      email: data.adminEmail,
+      passwordHash: hashedPassword,
+      nombre: data.adminNombre,
+      role: 'admin',
+    },
+  });
+
+  // 4. Create initial subscription
+  await prisma.subscription.create({
+    data: {
+      tenantId: tenant.id,
+      plan,
+      status: 'pending',
+      amount: data.amount,
+      frequency: 'monthly',
+    },
+  });
+
+  // 5. Send welcome email (non-blocking)
+  emailService.sendWelcome(data.adminEmail, {
+    nombre: data.adminNombre,
+    email: data.adminEmail,
+    tempPassword,
+  }).catch(err => console.error('[EMAIL] Welcome email failed:', err));
+
+  return { tenant, user, tempPassword };
 }
 
 export async function updateTenant(id: string, data: {