diff --git a/apps/api/prisma/schema.prisma b/apps/api/prisma/schema.prisma
new file mode 100644
index 0000000..449dc92
--- /dev/null
+++ b/apps/api/prisma/schema.prisma
@@ -0,0 +1,64 @@
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+model Tenant {
+  id          String    @id @default(uuid())
+  nombre      String
+  rfc         String    @unique
+  plan        Plan      @default(starter)
+  schemaName  String    @unique @map("schema_name")
+  cfdiLimit   Int       @map("cfdi_limit")
+  usersLimit  Int       @map("users_limit")
+  active      Boolean   @default(true)
+  createdAt   DateTime  @default(now()) @map("created_at")
+  expiresAt   DateTime? @map("expires_at")
+
+  users User[]
+
+  @@map("tenants")
+}
+
+model User {
+  id           String    @id @default(uuid())
+  tenantId     String    @map("tenant_id")
+  email        String    @unique
+  passwordHash String    @map("password_hash")
+  nombre       String
+  role         Role      @default(visor)
+  active       Boolean   @default(true)
+  lastLogin    DateTime? @map("last_login")
+  createdAt    DateTime  @default(now()) @map("created_at")
+
+  tenant Tenant @relation(fields: [tenantId], references: [id])
+
+  @@map("users")
+}
+
+model RefreshToken {
+  id        String   @id @default(uuid())
+  userId    String   @map("user_id")
+  token     String   @unique
+  expiresAt DateTime @map("expires_at")
+  createdAt DateTime @default(now()) @map("created_at")
+
+  @@map("refresh_tokens")
+}
+
+enum Plan {
+  starter
+  business
+  professional
+  enterprise
+}
+
+enum Role {
+  admin
+  contador
+  visor
+}
diff --git a/apps/api/src/config/database.ts b/apps/api/src/config/database.ts
new file mode 100644
index 0000000..df46150
--- /dev/null
+++ b/apps/api/src/config/database.ts
@@ -0,0 +1,13 @@
+import { PrismaClient } from '@prisma/client';
+
+declare global {
+  var prisma: PrismaClient | undefined;
+}
+
+export const prisma = globalThis.prisma || new PrismaClient({
+  log: process.env.NODE_ENV === 'development' ? ['query', 'error', 'warn'] : ['error'],
+});
+
+if (process.env.NODE_ENV !== 'production') {
+  globalThis.prisma = prisma;
+}
diff --git a/apps/api/src/utils/schema-manager.ts b/apps/api/src/utils/schema-manager.ts
new file mode 100644
index 0000000..7fe6e4f
--- /dev/null
+++ b/apps/api/src/utils/schema-manager.ts
@@ -0,0 +1,104 @@
+import { prisma } from '../config/database.js';
+
+export async function createTenantSchema(schemaName: string): Promise<void> {
+  await prisma.$executeRawUnsafe(`CREATE SCHEMA IF NOT EXISTS "${schemaName}"`);
+
+  await prisma.$executeRawUnsafe(`
+    CREATE TABLE IF NOT EXISTS "${schemaName}"."cfdis" (
+      id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+      uuid_fiscal VARCHAR(36) UNIQUE NOT NULL,
+      tipo VARCHAR(20) NOT NULL,
+      serie VARCHAR(25),
+      folio VARCHAR(40),
+      fecha_emision TIMESTAMP NOT NULL,
+      fecha_timbrado TIMESTAMP NOT NULL,
+      rfc_emisor VARCHAR(13) NOT NULL,
+      nombre_emisor VARCHAR(300) NOT NULL,
+      rfc_receptor VARCHAR(13) NOT NULL,
+      nombre_receptor VARCHAR(300) NOT NULL,
+      subtotal DECIMAL(18,2) NOT NULL,
+      descuento DECIMAL(18,2) DEFAULT 0,
+      iva DECIMAL(18,2) DEFAULT 0,
+      isr_retenido DECIMAL(18,2) DEFAULT 0,
+      iva_retenido DECIMAL(18,2) DEFAULT 0,
+      total DECIMAL(18,2) NOT NULL,
+      moneda VARCHAR(3) DEFAULT 'MXN',
+      tipo_cambio DECIMAL(10,4) DEFAULT 1,
+      metodo_pago VARCHAR(3),
+      forma_pago VARCHAR(2),
+      uso_cfdi VARCHAR(4),
+      estado VARCHAR(20) DEFAULT 'vigente',
+      xml_url TEXT,
+      pdf_url TEXT,
+      created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    )
+  `);
+
+  await prisma.$executeRawUnsafe(`
+    CREATE TABLE IF NOT EXISTS "${schemaName}"."iva_mensual" (
+      id SERIAL PRIMARY KEY,
+      año INTEGER NOT NULL,
+      mes INTEGER NOT NULL,
+      iva_trasladado DECIMAL(18,2) NOT NULL,
+      iva_acreditable DECIMAL(18,2) NOT NULL,
+      iva_retenido DECIMAL(18,2) DEFAULT 0,
+      resultado DECIMAL(18,2) NOT NULL,
+      acumulado DECIMAL(18,2) NOT NULL,
+      estado VARCHAR(20) DEFAULT 'pendiente',
+      fecha_declaracion TIMESTAMP,
+      UNIQUE(año, mes)
+    )
+  `);
+
+  await prisma.$executeRawUnsafe(`
+    CREATE TABLE IF NOT EXISTS "${schemaName}"."isr_mensual" (
+      id SERIAL PRIMARY KEY,
+      año INTEGER NOT NULL,
+      mes INTEGER NOT NULL,
+      ingresos_acumulados DECIMAL(18,2) NOT NULL,
+      deducciones DECIMAL(18,2) NOT NULL,
+      base_gravable DECIMAL(18,2) NOT NULL,
+      isr_causado DECIMAL(18,2) NOT NULL,
+      isr_retenido DECIMAL(18,2) NOT NULL,
+      isr_a_pagar DECIMAL(18,2) NOT NULL,
+      estado VARCHAR(20) DEFAULT 'pendiente',
+      fecha_declaracion TIMESTAMP,
+      UNIQUE(año, mes)
+    )
+  `);
+
+  await prisma.$executeRawUnsafe(`
+    CREATE TABLE IF NOT EXISTS "${schemaName}"."alertas" (
+      id SERIAL PRIMARY KEY,
+      tipo VARCHAR(50) NOT NULL,
+      titulo VARCHAR(200) NOT NULL,
+      mensaje TEXT NOT NULL,
+      prioridad VARCHAR(20) DEFAULT 'media',
+      fecha_vencimiento TIMESTAMP,
+      leida BOOLEAN DEFAULT FALSE,
+      resuelta BOOLEAN DEFAULT FALSE,
+      created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    )
+  `);
+
+  await prisma.$executeRawUnsafe(`
+    CREATE TABLE IF NOT EXISTS "${schemaName}"."calendario_fiscal" (
+      id SERIAL PRIMARY KEY,
+      titulo VARCHAR(200) NOT NULL,
+      descripcion TEXT,
+      tipo VARCHAR(50) NOT NULL,
+      fecha_limite TIMESTAMP NOT NULL,
+      recurrencia VARCHAR(20) DEFAULT 'unica',
+      completado BOOLEAN DEFAULT FALSE,
+      notas TEXT
+    )
+  `);
+}
+
+export async function setTenantSchema(schemaName: string): Promise<void> {
+  await prisma.$executeRawUnsafe(`SET search_path TO "${schemaName}"`);
+}
+
+export async function deleteTenantSchema(schemaName: string): Promise<void> {
+  await prisma.$executeRawUnsafe(`DROP SCHEMA IF EXISTS "${schemaName}" CASCADE`);
+}