diff --git a/modules/customer-invoices/src/api/application/customer-invoice-application.service.ts b/modules/customer-invoices/src/api/application/customer-invoice-application.service.ts
index d147da98..e8cc3a26 100644
--- a/modules/customer-invoices/src/api/application/customer-invoice-application.service.ts
+++ b/modules/customer-invoices/src/api/application/customer-invoice-application.service.ts
@@ -1,7 +1,12 @@
 import { Criteria } from "@repo/rdx-criteria/server";
 import { UniqueID } from "@repo/rdx-ddd";
-import { Collection, Result } from "@repo/rdx-utils";
+import { Collection, Maybe, Result } from "@repo/rdx-utils";
 import { Transaction } from "sequelize";
+import {
+  CustomerInvoiceNumber,
+  CustomerInvoiceSerie,
+  ICustomerInvoiceNumberGenerator,
+} from "../domain";
 import {
   CustomerInvoice,
   CustomerInvoicePatchProps,
@@ -11,17 +16,50 @@ import { ICustomerInvoiceRepository } from "../domain/repositories";
 import { CustomerInvoiceListDTO } from "../infrastructure";
 
 export class CustomerInvoiceApplicationService {
-  constructor(private readonly repository: ICustomerInvoiceRepository) {}
+  constructor(
+    private readonly repository: ICustomerInvoiceRepository,
+    private readonly numberGenerator: ICustomerInvoiceNumberGenerator
+  ) {}
 
   /**
-   * Construye un nuevo agregado CustomerInvoice a partir de props validadas.
+   * Devuelve el siguiente nº para proformas
+   *
+   * @param companyId - Identificador de la empresa a la que pertenece la proforma.
+   * @param transaction - Transacción activa para la operación.
+   * @returns Result<CustomerInvoiceNumber, Error> - El agregado construido o un error si falla la creación.
+   */
+  async getNextProformaNumber(
+    companyId: UniqueID,
+    transaction: Transaction
+  ): Promise<Result<CustomerInvoiceNumber, Error>> {
+    return await this.numberGenerator.nextForCompany(companyId, Maybe.none(), transaction);
+  }
+
+  /**
+   * Devuelve el siguiente nº para facturas (issue)
    *
    * @param companyId - Identificador de la empresa a la que pertenece la factura.
-   * @param props - Las propiedades ya validadas para crear la factura.
-   * @param invoiceId - Identificador UUID de la factura (opcional).
+   * @param series - Serie por la que buscar la última factura
+   * @param transaction - Transacción activa para la operación.
+   * @returns Result<CustomerInvoiceNumber, Error> - El agregado construido o un error si falla la creación.
+   */
+  async getNextIssueInvoiceNumber(
+    companyId: UniqueID,
+    series: Maybe<CustomerInvoiceSerie>,
+    transaction: Transaction
+  ): Promise<Result<CustomerInvoiceNumber, Error>> {
+    return await this.numberGenerator.nextForCompany(companyId, series, transaction);
+  }
+
+  /**
+   * Construye una proforma a partir de props validadas.
+   *
+   * @param companyId - Identificador de la empresa a la que pertenece la proforma.
+   * @param props - Las propiedades ya validadas para crear la proforma.
+   * @param invoiceId - Identificador UUID de la proforma (opcional).
    * @returns Result<CustomerInvoice, Error> - El agregado construido o un error si falla la creación.
    */
-  buildInvoiceInCompany(
+  buildProformaInCompany(
     companyId: UniqueID,
     props: Omit<CustomerInvoiceProps, "companyId">,
     invoiceId?: UniqueID
@@ -29,6 +67,28 @@ export class CustomerInvoiceApplicationService {
     return CustomerInvoice.create({ ...props, companyId }, invoiceId);
   }
 
+  /**
+   * Construye una factura issue a partir de una proforma.
+   *
+   * @param companyId - Identificador de la empresa a la que pertenece la factura.
+   * @param issueInvoiceId - Identificador UUID de la factura (opcional).
+   * @param proforma - La proforma de la cual se generará la issue
+   * @param pathcProps - otros props personalizados que se trasladarán a la issue
+   * @returns Result<CustomerInvoice, Error> - El agregado construido o un error si falla la creación.
+   */
+  buildIssueInvoiceInCompany(
+    companyId: UniqueID,
+    proforma: CustomerInvoice,
+    patchProps: CustomerInvoicePatchProps
+  ): Result<CustomerInvoice, Error> {
+    const proformaProps = proforma.getIssuedInvoiceProps();
+    return CustomerInvoice.create({
+      ...proformaProps,
+      ...patchProps,
+      companyId,
+    });
+  }
+
   /**
    * Guarda una nueva factura y devuelve la factura guardada.
    *
diff --git a/modules/customer-invoices/src/api/application/presenters/domain/customer-invoice.full.presenter.ts b/modules/customer-invoices/src/api/application/presenters/domain/customer-invoice.full.presenter.ts
index 2154d648..bae3ece1 100644
--- a/modules/customer-invoices/src/api/application/presenters/domain/customer-invoice.full.presenter.ts
+++ b/modules/customer-invoices/src/api/application/presenters/domain/customer-invoice.full.presenter.ts
@@ -47,7 +47,7 @@ export class CustomerInvoiceFullPresenter extends Presenter<
       id: invoice.id.toString(),
       company_id: invoice.companyId.toString(),
 
-      invoice_number: toEmptyString(invoice.invoiceNumber, (value) => value.toString()),
+      invoice_number: invoice.invoiceNumber.toString(),
       status: invoice.status.toPrimitive(),
       series: toEmptyString(invoice.series, (value) => value.toString()),
 
diff --git a/modules/customer-invoices/src/api/application/presenters/queries/list-customer-invoices.presenter.ts b/modules/customer-invoices/src/api/application/presenters/queries/list-customer-invoices.presenter.ts
index 7d0922d0..aeb8d6cd 100644
--- a/modules/customer-invoices/src/api/application/presenters/queries/list-customer-invoices.presenter.ts
+++ b/modules/customer-invoices/src/api/application/presenters/queries/list-customer-invoices.presenter.ts
@@ -15,7 +15,7 @@ export class ListCustomerInvoicesPresenter extends Presenter {
       is_proforma: invoice.isProforma,
       customer_id: invoice.customerId.toString(),
 
-      invoice_number: toEmptyString(invoice.invoiceNumber, (value) => value.toString()),
+      invoice_number: invoice.invoiceNumber.toString(),
       status: invoice.status.toPrimitive(),
       series: toEmptyString(invoice.series, (value) => value.toString()),
 
diff --git a/modules/customer-invoices/src/api/application/specs/index.ts b/modules/customer-invoices/src/api/application/specs/index.ts
deleted file mode 100644
index e5c2b414..00000000
--- a/modules/customer-invoices/src/api/application/specs/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-export * from "./status-invoice_is_approved.spec";
diff --git a/modules/customer-invoices/src/api/application/use-cases/create/create-customer-invoice.use-case.ts b/modules/customer-invoices/src/api/application/use-cases/create/create-customer-invoice.use-case.ts
index e59f12d4..e67b2206 100644
--- a/modules/customer-invoices/src/api/application/use-cases/create/create-customer-invoice.use-case.ts
+++ b/modules/customer-invoices/src/api/application/use-cases/create/create-customer-invoice.use-case.ts
@@ -1,7 +1,7 @@
 import { JsonTaxCatalogProvider } from "@erp/core";
 import { DuplicateEntityError, IPresenterRegistry, ITransactionManager } from "@erp/core/api";
 import { UniqueID } from "@repo/rdx-ddd";
-import { Result } from "@repo/rdx-utils";
+import { Maybe, Result } from "@repo/rdx-utils";
 import { Transaction } from "sequelize";
 import { CreateCustomerInvoiceRequestDTO } from "../../../../common/dto";
 import { CustomerInvoiceApplicationService } from "../../customer-invoice-application.service";
@@ -21,7 +21,7 @@ export class CreateCustomerInvoiceUseCase {
     private readonly taxCatalog: JsonTaxCatalogProvider
   ) {}
 
-  public execute(params: CreateCustomerInvoiceUseCaseInput) {
+  public async execute(params: CreateCustomerInvoiceUseCaseInput) {
     const { dto, companyId } = params;
     const presenter = this.presenterRegistry.getPresenter({
       resource: "customer-invoice",
@@ -37,17 +37,30 @@ export class CreateCustomerInvoiceUseCase {
 
     const { props, id } = dtoResult.data;
 
-    // 2) Construir entidad de dominio
-    const buildResult = this.service.buildInvoiceInCompany(companyId, props, id);
-    if (buildResult.isFailure) {
-      return Result.fail(buildResult.error);
-    }
-
-    const newInvoice = buildResult.data;
-
     // 3) Ejecutar bajo transacción: verificar duplicado → persistir → ensamblar vista
     return this.transactionManager.complete(async (transaction: Transaction) => {
       try {
+        // 2) Generar nuevo nº de proforma
+        const nextNumberResult = await this.service.getNextProformaNumber(companyId, transaction);
+        if (nextNumberResult.isFailure) {
+          return Result.fail(nextNumberResult.error);
+        }
+
+        const newProformaNumber = nextNumberResult.data;
+
+        // 3) Construir entidad de dominio
+        const proformaProps = {
+          ...props,
+          invoiceNumber: Maybe.some(newProformaNumber),
+        };
+
+        const buildResult = this.service.buildProformaInCompany(companyId, proformaProps, id);
+        if (buildResult.isFailure) {
+          return Result.fail(buildResult.error);
+        }
+
+        const newInvoice = buildResult.data;
+
         const existsGuard = await this.ensureNotExists(companyId, id, transaction);
         if (existsGuard.isFailure) {
           return Result.fail(existsGuard.error);
diff --git a/modules/customer-invoices/src/api/application/use-cases/issue-customer-invoice.use-case.ts b/modules/customer-invoices/src/api/application/use-cases/issue-customer-invoice.use-case.ts
index 360e6562..ed9174ba 100644
--- a/modules/customer-invoices/src/api/application/use-cases/issue-customer-invoice.use-case.ts
+++ b/modules/customer-invoices/src/api/application/use-cases/issue-customer-invoice.use-case.ts
@@ -1,15 +1,24 @@
-import { EntityNotFoundError, ITransactionManager } from "@erp/core/api";
-import { UniqueID } from "@repo/rdx-ddd";
-import { Result } from "@repo/rdx-utils";
-import { CustomerInvoiceNumber } from "../../domain";
+import { ITransactionManager } from "@erp/core/api";
+import { UniqueID, UtcDate } from "@repo/rdx-ddd";
+import { Maybe, Result } from "@repo/rdx-utils";
+import { InvalidProformaStatusError } from "../../domain";
+import { StatusInvoiceIsApprovedSpecification } from "../../domain/specs";
 import { CustomerInvoiceApplicationService } from "../customer-invoice-application.service";
-import { StatusInvoiceIsApprovedSpecification } from "../specs";
 
 type IssueCustomerInvoiceUseCaseInput = {
   companyId: UniqueID;
-  invoice_id: string;
+  proforma_id: string;
 };
 
+/**
+ * Caso de uso: Conversión de una proforma a factura definitiva.
+ *
+ * - Recupera la proforma
+ * - Valida su estado ("approved")
+ * - Genera la factura definitiva (nueva entidad)
+ * - Marca la proforma como "issued"
+ * - Persiste ambas dentro de la misma transacción
+ */
 export class IssueCustomerInvoiceUseCase {
   constructor(
     private readonly service: CustomerInvoiceApplicationService,
@@ -17,56 +26,78 @@ export class IssueCustomerInvoiceUseCase {
   ) {}
 
   public execute(params: IssueCustomerInvoiceUseCaseInput) {
-    const { invoice_id, companyId } = params;
+    const { proforma_id, companyId } = params;
 
-    const idOrError = UniqueID.create(invoice_id);
+    const idOrError = UniqueID.create(proforma_id);
 
     if (idOrError.isFailure) {
       return Result.fail(idOrError.error);
     }
 
-    const invoiceId = idOrError.data;
+    const proformaId = idOrError.data;
 
     return this.transactionManager.complete(async (transaction) => {
       try {
-        const invoiceResult = await this.service.getInvoiceByIdInCompany(
+        /** 1. Recuperamos la proforma */
+        const proformaResult = await this.service.getInvoiceByIdInCompany(
           companyId,
-          invoiceId,
+          proformaId,
           transaction
         );
 
-        if (invoiceResult.isFailure) {
-          return Result.fail(invoiceResult.error);
+        if (proformaResult.isFailure) {
+          return Result.fail(proformaResult.error);
         }
 
-        const invoiceProforma = invoiceResult.data;
+        const proforma = proformaResult.data;
 
-        const isOk = new StatusInvoiceIsApprovedSpecification().isSatisfiedBy(invoiceProforma);
-
-        if (!isOk) {
-          return Result.fail(
-            new EntityNotFoundError("Customer invoice", "id", invoiceId.toString())
-          );
+        /** 2. Comprobamos que la proforma origen está aprovada para generar la factura */
+        const isApprovedSpec = new StatusInvoiceIsApprovedSpecification();
+        if (!(await isApprovedSpec.isSatisfiedBy(proforma))) {
+          return Result.fail(new InvalidProformaStatusError(proformaId.toString()));
         }
 
-        // La factura se puede emitir.
-        // Pedir el número de factura
-        const newInvoiceNumber = CustomerInvoiceNumber.create("xxx/001").data;
-
-        // Asignamos el número de la factura
-
-        const issuedInvoiceResult = invoiceProforma.issueInvoice(newInvoiceNumber);
-        if (issuedInvoiceResult.isFailure) {
-          return Result.fail(
-            new EntityNotFoundError("Customer invoice", "id", issuedInvoiceResult.error)
-          );
+        /** 3. Generar nueva factura */
+        const nextNumberResult = await this.service.getNextIssueInvoiceNumber(
+          companyId,
+          proforma.series,
+          transaction
+        );
+        if (nextNumberResult.isFailure) {
+          return Result.fail(nextNumberResult.error);
         }
 
-        const issuedInvoice = issuedInvoiceResult.data;
+        const newIssueNumber = nextNumberResult.data;
 
-        this.service.updateInvoiceInCompany(companyId, issuedInvoice, transaction);
+        // props base obtenidas del agregado proforma
+        const issuedInvoiceOrError = this.service.buildIssueInvoiceInCompany(companyId, proforma, {
+          invoiceNumber: Maybe.some(newIssueNumber),
+          invoiceDate: UtcDate.today(),
+        });
 
-        //return await this.service.IssueInvoiceByIdInCompany(companyId, invoiceId, transaction);
+        if (issuedInvoiceOrError.isFailure) {
+          return Result.fail(issuedInvoiceOrError.error);
+        }
+
+        const issuedInvoice = issuedInvoiceOrError.data;
+
+        /** 4. Persistencia */
+        await this.service.createInvoiceInCompany(companyId, issuedInvoice, transaction);
+
+        // actualizamos la proforma
+        const updatedProformaResult = proforma.asIssued();
+        if (updatedProformaResult.isFailure) {
+          return Result.fail(updatedProformaResult.error);
+        }
+
+        await this.service.updateInvoiceInCompany(
+          companyId,
+          updatedProformaResult.data,
+          transaction
+        );
+
+        /** 5. Resultado */
+        return Result.ok(issuedInvoice);
       } catch (error: unknown) {
         return Result.fail(error as Error);
       }
diff --git a/modules/customer-invoices/src/api/application/use-cases/report/reporter/templates/customer-invoice/template.hbs b/modules/customer-invoices/src/api/application/use-cases/report/reporter/templates/customer-invoice/template.hbs
index 5e476aae..a8a3b756 100644
--- a/modules/customer-invoices/src/api/application/use-cases/report/reporter/templates/customer-invoice/template.hbs
+++ b/modules/customer-invoices/src/api/application/use-cases/report/reporter/templates/customer-invoice/template.hbs
@@ -175,7 +175,7 @@
             <td>{{description}}</td>
             <td class="text-right">{{#if quantity}}{{quantity}}{{else}}&nbsp;{{/if}}</td>
             <td class="text-right">{{#if unit_amount}}{{unit_amount}}{{else}}&nbsp;{{/if}}</td>
-            <td class="text-right">{{#if subtotal_amount}}{{subtotal_amount}}{{else}}&nbsp;{{/if}}</td>
+            <td class="text-right">{{#if total_amount}}{{total_amount}}{{else}}&nbsp;{{/if}}</td>
             </td>
           </tr>
           {{/each}}
diff --git a/modules/customer-invoices/src/api/domain/aggregates/customer-invoice.ts b/modules/customer-invoices/src/api/domain/aggregates/customer-invoice.ts
index f6c8b610..ba5b2a4a 100644
--- a/modules/customer-invoices/src/api/domain/aggregates/customer-invoice.ts
+++ b/modules/customer-invoices/src/api/domain/aggregates/customer-invoice.ts
@@ -24,8 +24,10 @@ export interface CustomerInvoiceProps {
   isProforma: boolean;
   status: CustomerInvoiceStatus;
 
+  proformaId: Maybe<UniqueID>;
+
   series: Maybe<CustomerInvoiceSerie>;
-  invoiceNumber: Maybe<CustomerInvoiceNumber>;
+  invoiceNumber: CustomerInvoiceNumber;
 
   invoiceDate: UtcDate;
   operationDate: Maybe<UtcDate>;
@@ -70,7 +72,9 @@ export interface ICustomerInvoice {
 
   getTaxes(): InvoiceTaxTotal[];
 
-  issueInvoice(newInvoiceNumber: CustomerInvoiceNumber): Result<CustomerInvoice, Error>;
+  asIssued(): Result<CustomerInvoice, Error>;
+
+  getIssuedInvoiceProps(): CustomerInvoiceProps;
 }
 
 export class CustomerInvoice
@@ -143,6 +147,10 @@ export class CustomerInvoice
     return this.props.isProforma;
   }
 
+  public get proformaId(): Maybe<UniqueID> {
+    return this.props.proformaId;
+  }
+
   public get status(): CustomerInvoiceStatus {
     return this.props.status;
   }
@@ -301,15 +309,21 @@ export class CustomerInvoice
     };
   }
 
-  public issueInvoice(newInvoiceNumber: CustomerInvoiceNumber) {
-    return CustomerInvoice.create(
-      {
-        ...this.props,
-        status: CustomerInvoiceStatus.createIssued(),
-        isProforma: false,
-        invoiceNumber: Maybe.some(newInvoiceNumber),
-      },
-      this.id
-    );
+  public asIssued(): Result<CustomerInvoice, Error> {
+    const newProps: CustomerInvoiceProps = {
+      ...this.props,
+      status: CustomerInvoiceStatus.createIssued(),
+    };
+    return CustomerInvoice.create(newProps, this.id);
+  }
+
+  public getIssuedInvoiceProps(): CustomerInvoiceProps {
+    return {
+      ...this.props,
+      isProforma: false,
+      proformaId: Maybe.some(this.id),
+      status: CustomerInvoiceStatus.createIssued(),
+      invoiceDate: UtcDate.today(),
+    };
   }
 }
diff --git a/modules/customer-invoices/src/api/domain/entities/customer-invoice-items/customer-invoice-item.test.ts b/modules/customer-invoices/src/api/domain/entities/customer-invoice-items/customer-invoice-item.test.ts
deleted file mode 100644
index 7698626d..00000000
--- a/modules/customer-invoices/src/api/domain/entities/customer-invoice-items/customer-invoice-item.test.ts
+++ /dev/null
@@ -1,85 +0,0 @@
-import { CurrencyCode, LanguageCode, MoneyValue, Percentage, Quantity } from "@repo/rdx-ddd";
-import { CustomerInvoiceItemDescription } from "../../value-objects";
-import { CustomerInvoiceItem } from "./customer-invoice-item";
-
-describe("CustomerInvoiceItem", () => {
-  it("debería calcular correctamente el subtotal (unitPrice * quantity)", () => {
-    const props = {
-      description: CustomerInvoiceItemDescription.create("Producto A"),
-      quantity: Quantity.create({ amount: 200, scale: 2 }),
-      unitPrice: MoneyValue.create(50),
-      discount: Percentage.create(0),
-      languageCode: LanguageCode.create("es"),
-      currencyCode: CurrencyCode.create("EUR"),
-    };
-
-    const result = CustomerInvoiceItem.create(props);
-
-    expect(result.isOk()).toBe(true);
-    const customerInvoiceItem = result.unwrap();
-    expect(customerInvoiceItem.subtotalPrice.value).toBe(100); // 50 * 2
-  });
-
-  it("debería calcular correctamente el total con descuento", () => {
-    const props = {
-      description: new CustomerInvoiceItemDescription("Producto B"),
-      quantity: new Quantity(3),
-      unitPrice: new MoneyValue(30),
-      discount: new Percentage(10), // 10%
-    };
-
-    const result = CustomerInvoiceItem.create(props);
-
-    expect(result.isOk()).toBe(true);
-    const customerInvoiceItem = result.unwrap();
-    expect(customerInvoiceItem.totalPrice.value).toBe(81); // (30 * 3) - 10% de (30 * 3)
-  });
-
-  it("debería devolver los valores correctos de las propiedades", () => {
-    const props = {
-      description: new CustomerInvoiceItemDescription("Producto C"),
-      quantity: new Quantity(1),
-      unitPrice: new MoneyValue(100),
-      discount: new Percentage(5),
-    };
-
-    const result = CustomerInvoiceItem.create(props);
-
-    expect(result.isOk()).toBe(true);
-    const customerInvoiceItem = result.unwrap();
-    expect(customerInvoiceItem.description.value).toBe("Producto C");
-    expect(customerInvoiceItem.quantity.value).toBe(1);
-    expect(customerInvoiceItem.unitPrice.value).toBe(100);
-    expect(customerInvoiceItem.discount.value).toBe(5);
-  });
-
-  it("debería manejar correctamente un descuento del 0%", () => {
-    const props = {
-      description: new CustomerInvoiceItemDescription("Producto D"),
-      quantity: new Quantity(4),
-      unitPrice: new MoneyValue(25),
-      discount: new Percentage(0),
-    };
-
-    const result = CustomerInvoiceItem.create(props);
-
-    expect(result.isOk()).toBe(true);
-    const customerInvoiceItem = result.unwrap();
-    expect(customerInvoiceItem.totalPrice.value).toBe(100); // 25 * 4
-  });
-
-  it("debería manejar correctamente un descuento del 100%", () => {
-    const props = {
-      description: new CustomerInvoiceItemDescription("Producto E"),
-      quantity: new Quantity(2),
-      unitPrice: new MoneyValue(50),
-      discount: new Percentage(100),
-    };
-
-    const result = CustomerInvoiceItem.create(props);
-
-    expect(result.isOk()).toBe(true);
-    const customerInvoiceItem = result.unwrap();
-    expect(customerInvoiceItem.totalPrice.value).toBe(0); // (50 * 2) - 100% de (50 * 2)
-  });
-});
diff --git a/modules/customer-invoices/src/api/domain/errors/index.ts b/modules/customer-invoices/src/api/domain/errors/index.ts
index b8c78e2f..45c0ddec 100644
--- a/modules/customer-invoices/src/api/domain/errors/index.ts
+++ b/modules/customer-invoices/src/api/domain/errors/index.ts
@@ -1 +1,2 @@
 export * from "./customer-invoice-id-already-exits-error";
+export * from "./invalid-proforma-status-error";
diff --git a/modules/customer-invoices/src/api/domain/errors/invalid-proforma-status-error.ts b/modules/customer-invoices/src/api/domain/errors/invalid-proforma-status-error.ts
new file mode 100644
index 00000000..970b4af8
--- /dev/null
+++ b/modules/customer-invoices/src/api/domain/errors/invalid-proforma-status-error.ts
@@ -0,0 +1,11 @@
+import { DomainError } from "@repo/rdx-ddd";
+
+export class InvalidProformaStatusError extends DomainError {
+  constructor(id: string, options?: ErrorOptions) {
+    super(`Error. Proforma with id '${id}' has invalid status.`, options);
+    this.name = "InvalidProformaStatusError";
+  }
+}
+
+export const isInvalidProformaStatusError = (e: unknown): e is InvalidProformaStatusError =>
+  e instanceof InvalidProformaStatusError;
diff --git a/modules/customer-invoices/src/api/domain/index.ts b/modules/customer-invoices/src/api/domain/index.ts
index 62b47e36..06917160 100644
--- a/modules/customer-invoices/src/api/domain/index.ts
+++ b/modules/customer-invoices/src/api/domain/index.ts
@@ -2,4 +2,6 @@ export * from "./aggregates";
 export * from "./entities";
 export * from "./errors";
 export * from "./repositories";
+export * from "./services";
+export * from "./specs";
 export * from "./value-objects";
diff --git a/modules/customer-invoices/src/api/domain/services/customer-invoice-number-generator.interface.ts b/modules/customer-invoices/src/api/domain/services/customer-invoice-number-generator.interface.ts
new file mode 100644
index 00000000..4808a802
--- /dev/null
+++ b/modules/customer-invoices/src/api/domain/services/customer-invoice-number-generator.interface.ts
@@ -0,0 +1,21 @@
+import { UniqueID } from "@repo/rdx-ddd";
+import { Maybe, Result } from "@repo/rdx-utils";
+import { CustomerInvoiceNumber, CustomerInvoiceSerie } from "../value-objects";
+
+/**
+ * Servicio de dominio que define cómo se genera el siguiente número de factura.
+ */
+export interface ICustomerInvoiceNumberGenerator {
+  /**
+   * Devuelve el siguiente número de factura disponible para una empresa dentro de una "serie" de factura.
+   *
+   * @param companyId - Identificador de la empresa
+   * @param serie - Serie por la que buscar la última factura
+   * @param transaction - Transacción activa
+   */
+  nextForCompany(
+    companyId: UniqueID,
+    series: Maybe<CustomerInvoiceSerie>,
+    transaction: any
+  ): Promise<Result<CustomerInvoiceNumber, Error>>;
+}
diff --git a/modules/customer-invoices/src/api/domain/services/index.ts b/modules/customer-invoices/src/api/domain/services/index.ts
new file mode 100644
index 00000000..e34a6999
--- /dev/null
+++ b/modules/customer-invoices/src/api/domain/services/index.ts
@@ -0,0 +1 @@
+export * from "./customer-invoice-number-generator.interface";
diff --git a/modules/customer-invoices/src/api/domain/specs/index.ts b/modules/customer-invoices/src/api/domain/specs/index.ts
new file mode 100644
index 00000000..37fb90f8
--- /dev/null
+++ b/modules/customer-invoices/src/api/domain/specs/index.ts
@@ -0,0 +1 @@
+export * from "./status-invoice-is-approved.specification";
diff --git a/modules/customer-invoices/src/api/application/specs/status-invoice_is_approved.spec.ts b/modules/customer-invoices/src/api/domain/specs/status-invoice-is-approved.specification.ts
similarity index 85%
rename from modules/customer-invoices/src/api/application/specs/status-invoice_is_approved.spec.ts
rename to modules/customer-invoices/src/api/domain/specs/status-invoice-is-approved.specification.ts
index a33a3b7d..87189689 100644
--- a/modules/customer-invoices/src/api/application/specs/status-invoice_is_approved.spec.ts
+++ b/modules/customer-invoices/src/api/domain/specs/status-invoice-is-approved.specification.ts
@@ -1,5 +1,5 @@
 import { CompositeSpecification } from "@repo/rdx-ddd";
-import { CustomerInvoice } from "../../domain";
+import { CustomerInvoice } from "../aggregates";
 
 export class StatusInvoiceIsApprovedSpecification extends CompositeSpecification<CustomerInvoice> {
   public async isSatisfiedBy(invoice: CustomerInvoice): Promise<boolean> {
diff --git a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-number.ts b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-number.ts
index 917bf399..acb8f116 100644
--- a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-number.ts
+++ b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-number.ts
@@ -7,7 +7,7 @@ interface ICustomerInvoiceNumberProps {
 }
 
 export class CustomerInvoiceNumber extends ValueObject<ICustomerInvoiceNumberProps> {
-  private static readonly MAX_LENGTH = 255;
+  private static readonly MAX_LENGTH = 12;
   private static readonly FIELD = "invoiceNumber";
   private static readonly ERROR_CODE = "INVALID_INVOICE_NUMBER";
 
diff --git a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-serie.ts b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-serie.ts
index c7e7dd08..6a0ae141 100644
--- a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-serie.ts
+++ b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-serie.ts
@@ -7,7 +7,7 @@ interface ICustomerInvoiceSerieProps {
 }
 
 export class CustomerInvoiceSerie extends ValueObject<ICustomerInvoiceSerieProps> {
-  private static readonly MAX_LENGTH = 255;
+  private static readonly MAX_LENGTH = 10;
   private static readonly FIELD = "invoiceSeries";
   private static readonly ERROR_CODE = "INVALID_INVOICE_SERIE";
 
diff --git a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-status.ts b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-status.ts
index 13b9f208..5fa59b4d 100644
--- a/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-status.ts
+++ b/modules/customer-invoices/src/api/domain/value-objects/customer-invoice-status.ts
@@ -11,8 +11,9 @@ export enum INVOICE_STATUS {
   APPROVED = "approved", // <- Proforma
   REJECTED = "rejected", // <- Proforma
 
-  // issued <- (si is_proforma === true) => Es una proforma (histórica)
-  // issued <- (si is_proforma === false) => Factura y enviada a Veri*Factu
+  // status === issued <- (si is_proforma === true) => Es una proforma (histórica)
+  // status === issued <- (si is_proforma === false) => Factura y enviará/enviada a Veri*Factu
+
   ISSUED = "issued",
 }
 export class CustomerInvoiceStatus extends ValueObject<ICustomerInvoiceStatusProps> {
diff --git a/modules/customer-invoices/src/api/infrastructure/dependencies.ts b/modules/customer-invoices/src/api/infrastructure/dependencies.ts
index 8636fe96..1318aecc 100644
--- a/modules/customer-invoices/src/api/infrastructure/dependencies.ts
+++ b/modules/customer-invoices/src/api/infrastructure/dependencies.ts
@@ -1,35 +1,32 @@
 // modules/invoice/infrastructure/invoice-dependencies.factory.ts
 
+import { JsonTaxCatalogProvider, SpainTaxCatalogProvider } from "@erp/core";
 import type { IMapperRegistry, IPresenterRegistry, ModuleParams } from "@erp/core/api";
-
 import {
   InMemoryMapperRegistry,
   InMemoryPresenterRegistry,
   SequelizeTransactionManager,
 } from "@erp/core/api";
-
 import {
   CreateCustomerInvoiceUseCase,
+  CustomerInvoiceApplicationService,
   CustomerInvoiceFullPresenter,
   CustomerInvoiceItemsFullPresenter,
+  CustomerInvoiceItemsReportPersenter,
   CustomerInvoiceReportHTMLPresenter,
   CustomerInvoiceReportPDFPresenter,
   CustomerInvoiceReportPresenter,
   GetCustomerInvoiceUseCase,
+  IssueCustomerInvoiceUseCase,
   ListCustomerInvoicesPresenter,
   ListCustomerInvoicesUseCase,
   RecipientInvoiceFullPresenter,
   ReportCustomerInvoiceUseCase,
   UpdateCustomerInvoiceUseCase,
 } from "../application";
-
-import { JsonTaxCatalogProvider, SpainTaxCatalogProvider } from "@erp/core";
-import {
-  CustomerInvoiceApplicationService,
-  CustomerInvoiceItemsReportPersenter,
-} from "../application";
 import { CustomerInvoiceDomainMapper, CustomerInvoiceListMapper } from "./mappers";
 import { CustomerInvoiceRepository } from "./sequelize";
+import { SequelizeInvoiceNumberGenerator } from "./services";
 
 export type CustomerInvoiceDeps = {
   transactionManager: SequelizeTransactionManager;
@@ -47,6 +44,7 @@ export type CustomerInvoiceDeps = {
     update: () => UpdateCustomerInvoiceUseCase;
     //delete: () => DeleteCustomerInvoiceUseCase;
     report: () => ReportCustomerInvoiceUseCase;
+    issue: () => IssueCustomerInvoiceUseCase;
   };
   getService: (name: string) => any;
   listServices: () => string[];
@@ -73,7 +71,8 @@ export function buildCustomerInvoiceDependencies(params: ModuleParams): Customer
 
   // Repository & Services
   const repo = new CustomerInvoiceRepository({ mapperRegistry, database });
-  const service = new CustomerInvoiceApplicationService(repo);
+  const numberGenerator = new SequelizeInvoiceNumberGenerator();
+  const service = new CustomerInvoiceApplicationService(repo, numberGenerator);
 
   // Presenter Registry
   const presenterRegistry = new InMemoryPresenterRegistry();
@@ -162,6 +161,7 @@ export function buildCustomerInvoiceDependencies(params: ModuleParams): Customer
       // delete: () => new DeleteCustomerInvoiceUseCase(service, transactionManager),
       report: () =>
         new ReportCustomerInvoiceUseCase(service, transactionManager, presenterRegistry),
+      issue: () => new IssueCustomerInvoiceUseCase(service, transactionManager),
     },
     listServices,
     getService,
diff --git a/modules/customer-invoices/src/api/infrastructure/express/controllers/issue-customer-invoice.controller.ts b/modules/customer-invoices/src/api/infrastructure/express/controllers/issue-customer-invoice.controller.ts
index 9d7a96d3..6ba8cb9b 100644
--- a/modules/customer-invoices/src/api/infrastructure/express/controllers/issue-customer-invoice.controller.ts
+++ b/modules/customer-invoices/src/api/infrastructure/express/controllers/issue-customer-invoice.controller.ts
@@ -1,21 +1,25 @@
-import { ExpressController, authGuard, forbidQueryFieldGuard, tenantGuard } from "@erp/core/api";
+import { authGuard, ExpressController, forbidQueryFieldGuard, tenantGuard } from "@erp/core/api";
 import { IssueCustomerInvoiceUseCase } from "../../../application";
 
 export class IssueCustomerInvoiceController extends ExpressController {
-  public constructor(
-    private readonly useCase: IssueCustomerInvoiceUseCase
-    /* private readonly presenter: any */
-  ) {
+  public constructor(private readonly useCase: IssueCustomerInvoiceUseCase) {
     super();
     // 🔐 Reutiliza guards de auth/tenant y prohíbe 'companyId' en query
     this.registerGuards(authGuard(), tenantGuard(), forbidQueryFieldGuard("companyId"));
   }
 
-  async executeImpl() {
-    const tenantId = this.getTenantId()!; // garantizado por tenantGuard
-    const { id } = this.req.params;
+  async executeImpl(): Promise<any> {
+    const companyId = this.getTenantId(); // garantizado por tenantGuard
+    if (!companyId) {
+      return this.forbiddenError("Tenant ID not found");
+    }
 
-    const result = await this.useCase.execute({ id, tenantId });
+    const { proforma_id } = this.req.params;
+    if (!proforma_id) {
+      return this.invalidInputError("Proforma ID missing");
+    }
+
+    const result = await this.useCase.execute({ proforma_id, companyId });
 
     return result.match(
       (data) => this.ok(data),
diff --git a/modules/customer-invoices/src/api/infrastructure/express/controllers/update-customer-invoice.controller.ts b/modules/customer-invoices/src/api/infrastructure/express/controllers/update-customer-invoice.controller.ts
index ad1f8d9d..6651cbb6 100644
--- a/modules/customer-invoices/src/api/infrastructure/express/controllers/update-customer-invoice.controller.ts
+++ b/modules/customer-invoices/src/api/infrastructure/express/controllers/update-customer-invoice.controller.ts
@@ -1,4 +1,4 @@
-import { ExpressController, authGuard, forbidQueryFieldGuard, tenantGuard } from "@erp/core/api";
+import { authGuard, ExpressController, forbidQueryFieldGuard, tenantGuard } from "@erp/core/api";
 import { UpdateCustomerInvoiceByIdRequestDTO } from "../../../../common/dto";
 import { UpdateCustomerInvoiceUseCase } from "../../../application";
 
@@ -14,10 +14,15 @@ export class UpdateCustomerInvoiceController extends ExpressController {
     if (!companyId) {
       return this.forbiddenError("Tenant ID not found");
     }
-    const { invoice_id } = this.req.params;
+
+    const { proforma_id } = this.req.params;
+    if (!proforma_id) {
+      return this.invalidInputError("Proforma ID missing");
+    }
+
     const dto = this.req.body as UpdateCustomerInvoiceByIdRequestDTO;
 
-    const result = await this.useCase.execute({ invoice_id, companyId, dto });
+    const result = await this.useCase.execute({ invoice_id: proforma_id, companyId, dto });
 
     return result.match(
       (data) => this.ok(data),
diff --git a/modules/customer-invoices/src/api/infrastructure/express/customer-invoices.routes.ts b/modules/customer-invoices/src/api/infrastructure/express/customer-invoices.routes.ts
index 8543ff7a..d7c09420 100644
--- a/modules/customer-invoices/src/api/infrastructure/express/customer-invoices.routes.ts
+++ b/modules/customer-invoices/src/api/infrastructure/express/customer-invoices.routes.ts
@@ -19,6 +19,7 @@ import {
   ReportCustomerInvoiceController,
   UpdateCustomerInvoiceController,
 } from "./controllers";
+import { IssueCustomerInvoiceController } from "./controllers/issue-customer-invoice.controller";
 
 export const customerInvoicesRouter = (params: ModuleParams) => {
   const { app, baseRoutePath, logger } = params as {
@@ -84,7 +85,7 @@ export const customerInvoicesRouter = (params: ModuleParams) => {
   );
 
   router.put(
-    "/:invoice_id",
+    "/:proforma_id",
     //checkTabContext,
 
     validateRequest(UpdateCustomerInvoiceByIdParamsRequestSchema, "params"),
@@ -117,18 +118,21 @@ export const customerInvoicesRouter = (params: ModuleParams) => {
       const controller = new ReportCustomerInvoiceController(useCase);
       return controller.execute(req, res, next);
     }
-  ); /*router.put(
-    "/:invoice_id/issue",
+  );
+
+  router.put(
+    "/:proforma_id/issue",
     //checkTabContext,
-    validateRequest(XXX, "params"),
-    validateRequest(XXX, "body"),
+
+    /*validateRequest(XXX, "params"),
+    validateRequest(XXX, "body"),*/
+
     (req: Request, res: Response, next: NextFunction) => {
       const useCase = deps.build.issue();
       const controller = new IssueCustomerInvoiceController(useCase);
       return controller.execute(req, res, next);
     }
-);
-*/
+  );
 
   app.use(`${baseRoutePath}/customer-invoices`, router);
 };
diff --git a/modules/customer-invoices/src/api/infrastructure/mappers/domain/customer-invoice.mapper.ts b/modules/customer-invoices/src/api/infrastructure/mappers/domain/customer-invoice.mapper.ts
index cb91f7ed..4c821fc9 100644
--- a/modules/customer-invoices/src/api/infrastructure/mappers/domain/customer-invoice.mapper.ts
+++ b/modules/customer-invoices/src/api/infrastructure/mappers/domain/customer-invoice.mapper.ts
@@ -70,6 +70,12 @@ export class CustomerInvoiceDomainMapper
 
     const isProforma = Boolean(source.is_proforma);
 
+    const proformaId = extractOrPushError(
+      maybeFromNullableVO(source.proforma_id, (v) => UniqueID.create(v)),
+      "proforma_id",
+      errors
+    );
+
     const status = extractOrPushError(
       CustomerInvoiceStatus.create(source.status),
       "status",
@@ -83,7 +89,7 @@ export class CustomerInvoiceDomainMapper
     );
 
     const invoiceNumber = extractOrPushError(
-      maybeFromNullableVO(source.invoice_number, (v) => CustomerInvoiceNumber.create(v)),
+      CustomerInvoiceNumber.create(source.invoice_number),
       "invoice_number",
       errors
     );
@@ -172,6 +178,7 @@ export class CustomerInvoiceDomainMapper
       companyId,
       customerId,
       isProforma,
+      proformaId,
       status,
       series,
       invoiceNumber,
@@ -204,13 +211,13 @@ export class CustomerInvoiceDomainMapper
         ...params,
       });
 
-      if (recipientResult.isFailure) {
+      /*if (recipientResult.isFailure) {
         errors.push({
           path: "recipient",
 
           message: recipientResult.error.message,
         });
-      }
+      }*/
 
       // 3) Items (colección)
       const itemsResults = this._itemsMapper.mapToDomainCollection(
@@ -223,12 +230,12 @@ export class CustomerInvoiceDomainMapper
         }
       );
 
-      if (itemsResults.isFailure) {
+      /*if (itemsResults.isFailure) {
         errors.push({
           path: "items",
           message: itemsResults.error.message,
         });
-      }
+      }*/
 
       // Nota: los impuestos a nivel factura (tabla customer_invoice_taxes) se derivan de los items.
       // El agregado expone un getter `taxes` (derivado). No se incluye en las props.
@@ -254,6 +261,7 @@ export class CustomerInvoiceDomainMapper
         companyId: attributes.companyId!,
 
         isProforma: attributes.isProforma,
+        proformaId: attributes.proformaId!,
         status: attributes.status!,
         series: attributes.series!,
         invoiceNumber: attributes.invoiceNumber!,
@@ -333,7 +341,7 @@ export class CustomerInvoiceDomainMapper
     const allAmounts = source.getAllAmounts();
 
     // 4) Cliente
-    const recipient = this._mapRecipientToPersistence(source, {
+    const recipient = this._recipientMapper.mapToPersistence(source.recipient, {
       errors,
       parent: source,
       ...params,
@@ -346,16 +354,17 @@ export class CustomerInvoiceDomainMapper
       );
     }
 
-    const invoiceValues: CustomerInvoiceCreationAttributes = {
+    const invoiceValues: Partial<CustomerInvoiceCreationAttributes> = {
       // Identificación
       id: source.id.toPrimitive(),
       company_id: source.companyId.toPrimitive(),
 
       // Flags / estado / serie / número
       is_proforma: source.isProforma,
+      proforma_id: toNullable(source.proformaId, (v) => v.toPrimitive()),
       status: source.status.toPrimitive(),
       series: toNullable(source.series, (v) => v.toPrimitive()),
-      invoice_number: toNullable(source.invoiceNumber, (v) => v.toPrimitive()),
+      invoice_number: source.invoiceNumber.toPrimitive(),
 
       invoice_date: source.invoiceDate.toPrimitive(),
       operation_date: toNullable(source.operationDate, (v) => v.toPrimitive()),
@@ -397,47 +406,8 @@ export class CustomerInvoiceDomainMapper
       items,
     };
 
-    return Result.ok<CustomerInvoiceCreationAttributes>(invoiceValues);
-  }
-
-  protected _mapRecipientToPersistence(source: CustomerInvoice, params?: MapperParamsType) {
-    const { errors } = params as {
-      errors: ValidationErrorDetail[];
-    };
-
-    const hasRecipient = source.hasRecipient;
-    const recipient = source.recipient?.getOrUndefined();
-
-    if (!source.isProforma && !hasRecipient) {
-      errors.push({
-        path: "recipient",
-        message: "[CustomerInvoiceDomainMapper] Issued customer invoice w/o recipient data",
-      });
-    }
-
-    const recipientValues = {
-      customer_tin: !source.isProforma ? recipient?.tin.toPrimitive() : null,
-      customer_name: !source.isProforma ? recipient?.name.toPrimitive() : null,
-      customer_street: !source.isProforma
-        ? toNullable(recipient?.street, (v) => v.toPrimitive())
-        : null,
-      customer_street2: !source.isProforma
-        ? toNullable(recipient?.street2, (v) => v.toPrimitive())
-        : null,
-      customer_city: !source.isProforma
-        ? toNullable(recipient?.city, (v) => v.toPrimitive())
-        : null,
-      customer_province: !source.isProforma
-        ? toNullable(recipient?.province, (v) => v.toPrimitive())
-        : null,
-      customer_postal_code: !source.isProforma
-        ? toNullable(recipient?.postalCode, (v) => v.toPrimitive())
-        : null,
-      customer_country: !source.isProforma
-        ? toNullable(recipient?.country, (v) => v.toPrimitive())
-        : null,
-    };
-
-    return recipientValues;
+    return Result.ok<CustomerInvoiceCreationAttributes>(
+      invoiceValues as CustomerInvoiceCreationAttributes
+    );
   }
 }
diff --git a/modules/customer-invoices/src/api/infrastructure/mappers/domain/invoice-recipient.mapper.ts b/modules/customer-invoices/src/api/infrastructure/mappers/domain/invoice-recipient.mapper.ts
index 411b9c63..6f0c3858 100644
--- a/modules/customer-invoices/src/api/infrastructure/mappers/domain/invoice-recipient.mapper.ts
+++ b/modules/customer-invoices/src/api/infrastructure/mappers/domain/invoice-recipient.mapper.ts
@@ -1,20 +1,20 @@
+import { MapperParamsType } from "@erp/core/api";
 import {
   City,
   Country,
+  extractOrPushError,
+  maybeFromNullableVO,
   Name,
   PostalCode,
   Province,
   Street,
   TINNumber,
+  toNullable,
   ValidationErrorCollection,
   ValidationErrorDetail,
-  extractOrPushError,
-  maybeFromNullableVO,
 } from "@repo/rdx-ddd";
-
-import { MapperParamsType } from "@erp/core/api";
 import { Maybe, Result } from "@repo/rdx-utils";
-import { CustomerInvoiceProps, InvoiceRecipient } from "../../../domain";
+import { CustomerInvoice, CustomerInvoiceProps, InvoiceRecipient } from "../../../domain";
 import { CustomerInvoiceModel } from "../../sequelize";
 
 export class InvoiceRecipientDomainMapper {
@@ -114,4 +114,64 @@ export class InvoiceRecipientDomainMapper {
 
     return Result.ok(Maybe.some(createResult.data));
   }
+
+  /**
+   * Mapea los datos del destinatario (recipient) de una factura de cliente
+   * al formato esperado por la capa de persistencia.
+   *
+   * Reglas:
+   *  - Si la factura es proforma (`isProforma === true`), todos los campos de recipient son `null`.
+   *  - Si la factura no es proforma (`isProforma === false`), debe existir `recipient`.
+   *    En caso contrario, se agrega un error de validación.
+   */
+  mapToPersistence(source: Maybe<InvoiceRecipient>, params?: MapperParamsType) {
+    const { errors, parent } = params as {
+      parent: CustomerInvoice;
+      errors: ValidationErrorDetail[];
+    };
+
+    const { isProforma, hasRecipient } = parent;
+
+    // Validación: facturas emitidas deben tener destinatario.
+    if (!isProforma && !hasRecipient) {
+      errors.push({
+        path: "recipient",
+        message: "[CustomerInvoiceDomainMapper] Issued customer invoice without recipient data",
+      });
+    }
+
+    // Si hay errores previos, devolvemos fallo de validación inmediatamente.
+    if (errors.length > 0) {
+      return Result.fail(
+        new ValidationErrorCollection("Customer invoice mapping to persistence failed", errors)
+      );
+    }
+
+    // Si es proforma o no hay destinatario, todos los campos deben ser null.
+    if (isProforma || source.isNone()) {
+      return {
+        customer_tin: null,
+        customer_name: null,
+        customer_street: null,
+        customer_street2: null,
+        customer_city: null,
+        customer_province: null,
+        customer_postal_code: null,
+        customer_country: null,
+      };
+    }
+
+    const recipient = source.unwrap();
+
+    return {
+      customer_tin: recipient.tin.toPrimitive(),
+      customer_name: recipient.name.toPrimitive(),
+      customer_street: toNullable(recipient.street, (v) => v.toPrimitive()),
+      customer_street2: toNullable(recipient.street2, (v) => v.toPrimitive()),
+      customer_city: toNullable(recipient.city, (v) => v.toPrimitive()),
+      customer_province: toNullable(recipient.province, (v) => v.toPrimitive()),
+      customer_postal_code: toNullable(recipient.postalCode, (v) => v.toPrimitive()),
+      customer_country: toNullable(recipient.country, (v) => v.toPrimitive()),
+    };
+  }
 }
diff --git a/modules/customer-invoices/src/api/infrastructure/mappers/queries/customer-invoice.list.mapper.ts b/modules/customer-invoices/src/api/infrastructure/mappers/queries/customer-invoice.list.mapper.ts
index 433be285..9780d7e1 100644
--- a/modules/customer-invoices/src/api/infrastructure/mappers/queries/customer-invoice.list.mapper.ts
+++ b/modules/customer-invoices/src/api/infrastructure/mappers/queries/customer-invoice.list.mapper.ts
@@ -27,7 +27,7 @@ export type CustomerInvoiceListDTO = {
   companyId: UniqueID;
 
   isProforma: boolean;
-  invoiceNumber: Maybe<CustomerInvoiceNumber>;
+  invoiceNumber: CustomerInvoiceNumber;
   status: CustomerInvoiceStatus;
   series: Maybe<CustomerInvoiceSerie>;
 
@@ -152,7 +152,7 @@ export class CustomerInvoiceListMapper
     );
 
     const invoiceNumber = extractOrPushError(
-      maybeFromNullableVO(raw.invoice_number, (value) => CustomerInvoiceNumber.create(value)),
+      CustomerInvoiceNumber.create(raw.invoice_number),
       "invoice_number",
       errors
     );
diff --git a/modules/customer-invoices/src/api/infrastructure/sequelize/models/customer-invoice.model.ts b/modules/customer-invoices/src/api/infrastructure/sequelize/models/customer-invoice.model.ts
index d80f4ee0..e28f2928 100644
--- a/modules/customer-invoices/src/api/infrastructure/sequelize/models/customer-invoice.model.ts
+++ b/modules/customer-invoices/src/api/infrastructure/sequelize/models/customer-invoice.model.ts
@@ -45,7 +45,7 @@ export class CustomerInvoiceModel extends Model<
   declare proforma_id: CreationOptional<string | null>; // ID de la proforma origen de la factura
 
   declare series: CreationOptional<string | null>;
-  declare invoice_number: CreationOptional<string | null>;
+  declare invoice_number: CreationOptional<string>;
   declare invoice_date: CreationOptional<string>;
   declare operation_date: CreationOptional<string | null>;
   declare language_code: CreationOptional<string>;
@@ -183,7 +183,7 @@ export default (database: Sequelize) => {
       proforma_id: {
         type: DataTypes.UUID,
         allowNull: true,
-        defaultValue: true,
+        defaultValue: null,
       },
 
       status: {
@@ -193,13 +193,13 @@ export default (database: Sequelize) => {
       },
 
       series: {
-        type: new DataTypes.STRING(),
+        type: new DataTypes.STRING(10),
         allowNull: true,
         defaultValue: null,
       },
 
       invoice_number: {
-        type: new DataTypes.STRING(),
+        type: new DataTypes.STRING(12),
         allowNull: true,
         defaultValue: null,
       },
@@ -404,10 +404,22 @@ export default (database: Sequelize) => {
           name: "idx_invoices_company_date",
           fields: ["company_id", "deleted_at", { name: "invoice_date", order: "DESC" }],
         },
+
+        {
+          name: "idx_invoice_company_series_number",
+          fields: ["company_id", "series", "invoice_number"],
+          unique: true,
+        }, // <- para consulta get
+
         { name: "idx_invoice_date", fields: ["invoice_date"] }, // <- para ordenación
-        { name: "idx_company_idx", fields: ["id", "company_id"], unique: true }, // <- para consulta get
-        { name: "idx_proforma_id", fields: ["proforma_id"], unique: false },
-        { name: "idx_factuges", fields: ["factuges_id"], unique: false }, // <- para el proceso python
+
+        { name: "idx_invoice_company_id", fields: ["id", "company_id"], unique: true }, // <- para consulta get
+
+        { name: "idx_invoice_proforma_id", fields: ["proforma_id"], unique: false }, // <- para localizar factura por medio de proforma
+
+        { name: "idx_invoice_factuges", fields: ["factuges_id"], unique: false }, // <- para el proceso python
+
+        // Para búsquedas simples
         {
           name: "ft_customer_invoice",
           type: "FULLTEXT",
diff --git a/modules/customer-invoices/src/api/infrastructure/services/index.ts b/modules/customer-invoices/src/api/infrastructure/services/index.ts
new file mode 100644
index 00000000..04236857
--- /dev/null
+++ b/modules/customer-invoices/src/api/infrastructure/services/index.ts
@@ -0,0 +1 @@
+export * from "./sequelize-invoice-number-generator";
diff --git a/modules/customer-invoices/src/api/infrastructure/services/sequelize-invoice-number-generator.ts b/modules/customer-invoices/src/api/infrastructure/services/sequelize-invoice-number-generator.ts
new file mode 100644
index 00000000..ad54dd25
--- /dev/null
+++ b/modules/customer-invoices/src/api/infrastructure/services/sequelize-invoice-number-generator.ts
@@ -0,0 +1,68 @@
+import { UniqueID } from "@repo/rdx-ddd";
+import { Maybe, Result } from "@repo/rdx-utils";
+import { literal, Transaction, WhereOptions } from "sequelize";
+import {
+  CustomerInvoiceNumber,
+  CustomerInvoiceSerie,
+  ICustomerInvoiceNumberGenerator,
+} from "../../domain";
+import { CustomerInvoiceModel } from "../sequelize";
+
+/**
+ * Generador de números de factura
+ */
+export class SequelizeInvoiceNumberGenerator implements ICustomerInvoiceNumberGenerator {
+  public async nextForCompany(
+    companyId: UniqueID,
+    series: Maybe<CustomerInvoiceSerie>,
+    transaction: Transaction
+  ): Promise<Result<CustomerInvoiceNumber, Error>> {
+    const where: WhereOptions = {
+      company_id: companyId.toString(),
+      is_proforma: false,
+    };
+
+    series.match(
+      (serieVO) => {
+        where.series = serieVO.toString();
+      },
+      () => {
+        where.series = null;
+      }
+    );
+
+    try {
+      const lastInvoice = await CustomerInvoiceModel.findOne({
+        attributes: ["invoice_number"],
+        where,
+        // Orden numérico real: CAST(... AS UNSIGNED)
+        order: [literal("CAST(invoice_number AS UNSIGNED) DESC")],
+        transaction,
+        raw: true,
+        // Bloqueo opcional para evitar carreras si estás dentro de una TX
+        lock: transaction.LOCK.UPDATE, // requiere InnoDB y TX abierta
+      });
+
+      let nextValue = "00001"; // valor inicial por defecto
+
+      if (lastInvoice) {
+        const current = Number(lastInvoice.invoice_number);
+        const next = Number.isFinite(current) && current > 0 ? current + 1 : 1;
+        nextValue = String(next).padStart(5, "0");
+      }
+
+      const numberResult = CustomerInvoiceNumber.create(nextValue);
+      if (numberResult.isFailure) {
+        return Result.fail(numberResult.error);
+      }
+
+      return Result.ok(numberResult.data);
+    } catch (error) {
+      return Result.fail(
+        new Error(
+          `Error generating invoice number for company ${companyId}: ${(error as Error).message}`
+        )
+      );
+    }
+  }
+}
diff --git a/modules/customers/src/api/infrastructure/mappers/domain/customer.mapper.ts b/modules/customers/src/api/infrastructure/mappers/domain/customer.mapper.ts
index e610b8fb..0332d7e1 100644
--- a/modules/customers/src/api/infrastructure/mappers/domain/customer.mapper.ts
+++ b/modules/customers/src/api/infrastructure/mappers/domain/customer.mapper.ts
@@ -4,25 +4,25 @@ import {
   Country,
   CurrencyCode,
   EmailAddress,
+  extractOrPushError,
   LanguageCode,
+  maybeFromNullableVO,
   Name,
   PhoneNumber,
   PostalAddress,
   PostalCode,
   Province,
   Street,
-  TINNumber,
   TaxCode,
   TextValue,
-  URLAddress,
+  TINNumber,
+  toNullable,
   UniqueID,
+  URLAddress,
   ValidationErrorCollection,
   ValidationErrorDetail,
-  extractOrPushError,
-  maybeFromNullableVO,
-  toNullable,
 } from "@repo/rdx-ddd";
-import { Collection, Result, isNullishOrEmpty } from "@repo/rdx-utils";
+import { Collection, isNullishOrEmpty, Result } from "@repo/rdx-utils";
 import { Customer, CustomerProps, CustomerStatus } from "../../../domain";
 import { CustomerCreationAttributes, CustomerModel } from "../../sequelize";