diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 34c7bf71..535e0be9 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -24,7 +24,7 @@ jobs:
       - name: Setup pnpm
         uses: pnpm/action-setup@v4
         with:
-          version: 10.15.0
+          version: 10.25.0
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
diff --git a/.github/workflows/security.yml b/.github/workflows/security.yml
index d8070c40..0f967160 100644
--- a/.github/workflows/security.yml
+++ b/.github/workflows/security.yml
@@ -22,7 +22,7 @@ jobs:
       - name: Setup pnpm
         uses: pnpm/action-setup@v4
         with:
-          version: 10.15.0
+          version: 10.25.0
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
diff --git a/apps/portal/Dockerfile b/apps/portal/Dockerfile
index 2fd67816..7fe5d6d7 100644
--- a/apps/portal/Dockerfile
+++ b/apps/portal/Dockerfile
@@ -6,7 +6,7 @@
 # =============================================================================
 
 ARG NODE_VERSION=22
-ARG PNPM_VERSION=10.15.0
+ARG PNPM_VERSION=10.25.0
 
 # =============================================================================
 # Stage 1: Builder
diff --git a/apps/portal/tsconfig.json b/apps/portal/tsconfig.json
index 10b60af0..98726133 100644
--- a/apps/portal/tsconfig.json
+++ b/apps/portal/tsconfig.json
@@ -2,7 +2,7 @@
   "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "target": "ES2022",
-    "lib": ["ES2024", "DOM", "DOM.Iterable"],
+    "lib": ["ESNext", "DOM", "DOM.Iterable"],
     "module": "ESNext",
     "moduleResolution": "Bundler",
     "jsx": "preserve",
diff --git a/packages/domain/auth/contract.ts b/packages/domain/auth/contract.ts
index a028fa9f..72a37ef6 100644
--- a/packages/domain/auth/contract.ts
+++ b/packages/domain/auth/contract.ts
@@ -77,4 +77,4 @@ export type {
   LinkWhmcsResponse,
   // Error types
   AuthError,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/auth/helpers.ts b/packages/domain/auth/helpers.ts
index 23cc0351..dc66dfd9 100644
--- a/packages/domain/auth/helpers.ts
+++ b/packages/domain/auth/helpers.ts
@@ -1,6 +1,6 @@
 import type { z } from "zod";
 
-import { signupRequestSchema } from "./schema";
+import { signupRequestSchema } from "./schema.js";
 
 type SignupRequestInput = z.input<typeof signupRequestSchema>;
 
diff --git a/packages/domain/auth/index.ts b/packages/domain/auth/index.ts
index 029425c5..e8d19e4e 100644
--- a/packages/domain/auth/index.ts
+++ b/packages/domain/auth/index.ts
@@ -20,7 +20,7 @@ export {
   type AuthErrorCode,
   type TokenTypeValue,
   type GenderValue,
-} from "./contract";
+} from "./contract.js";
 
 export type {
   // Request types
@@ -48,7 +48,7 @@ export type {
   LinkWhmcsResponse,
   // Error types
   AuthError,
-} from "./contract";
+} from "./contract.js";
 
 // ============================================================================
 // Schemas (for validation)
@@ -83,9 +83,9 @@ export {
   ssoLinkResponseSchema,
   checkPasswordNeededResponseSchema,
   linkWhmcsResponseSchema,
-} from "./schema";
+} from "./schema.js";
 
-export { buildSignupRequest } from "./helpers";
+export { buildSignupRequest } from "./helpers.js";
 
 // ============================================================================
 // Password Utilities
@@ -98,4 +98,4 @@ export {
   MIGRATION_TRANSFER_ITEMS,
   MIGRATION_STEPS,
   type PasswordRequirementKey,
-} from "./forms";
+} from "./forms.js";
diff --git a/packages/domain/auth/schema.ts b/packages/domain/auth/schema.ts
index 353d04f9..41c8b0ce 100644
--- a/packages/domain/auth/schema.ts
+++ b/packages/domain/auth/schema.ts
@@ -12,8 +12,8 @@
 
 import { z } from "zod";
 
-import { emailSchema, nameSchema, passwordSchema, phoneSchema } from "../common/schema";
-import { addressSchema, userSchema } from "../customer/schema";
+import { emailSchema, nameSchema, passwordSchema, phoneSchema } from "../common/schema.js";
+import { addressSchema, userSchema } from "../customer/schema.js";
 
 // ============================================================================
 // Authentication Request Schemas
diff --git a/packages/domain/billing/constants.ts b/packages/domain/billing/constants.ts
index 1205b51d..0bf8cb42 100644
--- a/packages/domain/billing/constants.ts
+++ b/packages/domain/billing/constants.ts
@@ -4,7 +4,7 @@
  * Domain constants for billing validation and business rules.
  */
 
-import type { WhmcsCurrency } from "./providers/whmcs/raw.types";
+import type { WhmcsCurrency } from "./providers/whmcs/raw.types.js";
 
 // ============================================================================
 // Currency Defaults
diff --git a/packages/domain/billing/contract.ts b/packages/domain/billing/contract.ts
index 53e19811..a2d689ba 100644
--- a/packages/domain/billing/contract.ts
+++ b/packages/domain/billing/contract.ts
@@ -35,5 +35,5 @@ export type {
   BillingSummary,
   InvoiceQueryParams,
   InvoiceListQuery,
-} from './schema';
+} from './schema.js';
 
diff --git a/packages/domain/billing/index.ts b/packages/domain/billing/index.ts
index 54e9c84a..f9e8e87d 100644
--- a/packages/domain/billing/index.ts
+++ b/packages/domain/billing/index.ts
@@ -7,11 +7,11 @@
  */
 
 // Constants
-export { INVOICE_STATUS } from "./contract";
-export * from "./constants";
+export { INVOICE_STATUS } from "./contract.js";
+export * from "./constants.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Re-export types for convenience
 export type {
@@ -25,10 +25,10 @@ export type {
   BillingSummary,
   InvoiceQueryParams,
   InvoiceListQuery,
-} from './schema';
+} from './schema.js';
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider raw types (request and response)
 export type {
@@ -45,4 +45,4 @@ export type {
   WhmcsCapturePaymentResponse,
   WhmcsCurrency,
   WhmcsCurrenciesResponse,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
diff --git a/packages/domain/billing/providers/index.ts b/packages/domain/billing/providers/index.ts
index d1a74140..f50c5a27 100644
--- a/packages/domain/billing/providers/index.ts
+++ b/packages/domain/billing/providers/index.ts
@@ -2,8 +2,8 @@
  * Billing Domain - Providers
  */
 
-import * as WhmcsMapper from "./whmcs/mapper";
-import * as WhmcsRaw from "./whmcs/raw.types";
+import * as WhmcsMapper from "./whmcs/mapper.js";
+import * as WhmcsRaw from "./whmcs/raw.types.js";
 
 export const Whmcs = {
   ...WhmcsMapper,
@@ -12,5 +12,5 @@ export const Whmcs = {
 };
 
 export { WhmcsMapper, WhmcsRaw };
-export * from "./whmcs/mapper";
-export * from "./whmcs/raw.types";
+export * from "./whmcs/mapper.js";
+export * from "./whmcs/raw.types.js";
diff --git a/packages/domain/billing/providers/whmcs/index.ts b/packages/domain/billing/providers/whmcs/index.ts
index c95a1ab4..644fdb12 100644
--- a/packages/domain/billing/providers/whmcs/index.ts
+++ b/packages/domain/billing/providers/whmcs/index.ts
@@ -1,2 +1,2 @@
-export * from "./mapper";
-export * from "./raw.types";
+export * from "./mapper.js";
+export * from "./raw.types.js";
diff --git a/packages/domain/billing/providers/whmcs/mapper.ts b/packages/domain/billing/providers/whmcs/mapper.ts
index 15c5e447..24e16636 100644
--- a/packages/domain/billing/providers/whmcs/mapper.ts
+++ b/packages/domain/billing/providers/whmcs/mapper.ts
@@ -4,8 +4,8 @@
  * Transforms raw WHMCS invoice data into normalized billing domain types.
  */
 
-import type { Invoice, InvoiceItem } from "../../contract";
-import { invoiceSchema } from "../../schema";
+import type { Invoice, InvoiceItem } from "../../contract.js";
+import { invoiceSchema } from "../../schema.js";
 import {
   type WhmcsInvoiceRaw,
   whmcsInvoiceRawSchema,
@@ -13,8 +13,8 @@ import {
   whmcsInvoiceListItemSchema,
   type WhmcsInvoiceItemsRaw,
   whmcsInvoiceItemsRawSchema,
-} from "./raw.types";
-import { parseAmount, formatDate } from "../../../providers/whmcs/utils";
+} from "./raw.types.js";
+import { parseAmount, formatDate } from "../../../providers/whmcs/utils.js";
 
 export interface TransformInvoiceOptions {
   defaultCurrencyCode?: string;
diff --git a/packages/domain/catalog/contract.ts b/packages/domain/catalog/contract.ts
index 0a6d56b6..0c6e1d2a 100644
--- a/packages/domain/catalog/contract.ts
+++ b/packages/domain/catalog/contract.ts
@@ -91,4 +91,4 @@ export type {
   VpnCatalogProduct,
   // Union type
   CatalogProduct,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/catalog/index.ts b/packages/domain/catalog/index.ts
index d35171fc..1bfe33d9 100644
--- a/packages/domain/catalog/index.ts
+++ b/packages/domain/catalog/index.ts
@@ -12,10 +12,10 @@ export {
   type PricingTier,
   type CatalogFilter,
   type CatalogPriceInfo,
-} from "./contract";
+} from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Re-export types for convenience
 export type {
@@ -34,23 +34,23 @@ export type {
   VpnCatalogProduct,
   // Union type
   CatalogProduct,
-} from './schema';
+} from './schema.js';
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider raw types for convenience
-export * from "./providers/salesforce/raw.types";
+export * from "./providers/salesforce/raw.types.js";
 
 // Re-export WHMCS provider types
 export type {
   WhmcsCatalogProduct,
   WhmcsCatalogProductListResponse,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
 export type {
   WhmcsCatalogProductNormalized,
   WhmcsCatalogPricing,
-} from "./providers/whmcs/mapper";
+} from "./providers/whmcs/mapper.js";
 
 // Utilities
-export * from "./utils";
+export * from "./utils.js";
diff --git a/packages/domain/catalog/providers/index.ts b/packages/domain/catalog/providers/index.ts
index ffaa4c59..d98b3d15 100644
--- a/packages/domain/catalog/providers/index.ts
+++ b/packages/domain/catalog/providers/index.ts
@@ -2,10 +2,10 @@
  * Catalog Domain - Providers
  */
 
-import * as SalesforceMapper from "./salesforce/mapper";
-import * as SalesforceRaw from "./salesforce/raw.types";
-import * as WhmcsMapper from "./whmcs/mapper";
-import * as WhmcsRaw from "./whmcs/raw.types";
+import * as SalesforceMapper from "./salesforce/mapper.js";
+import * as SalesforceRaw from "./salesforce/raw.types.js";
+import * as WhmcsMapper from "./whmcs/mapper.js";
+import * as WhmcsRaw from "./whmcs/raw.types.js";
 
 export const Salesforce = {
   ...SalesforceMapper,
@@ -19,7 +19,7 @@ export const Whmcs = {
 };
 
 export { SalesforceMapper, SalesforceRaw, WhmcsMapper, WhmcsRaw };
-export * from "./salesforce/mapper";
-export * from "./salesforce/raw.types";
-export * from "./whmcs/mapper";
-export * from "./whmcs/raw.types";
+export * from "./salesforce/mapper.js";
+export * from "./salesforce/raw.types.js";
+export * from "./whmcs/mapper.js";
+export * from "./whmcs/raw.types.js";
diff --git a/packages/domain/catalog/providers/salesforce/index.ts b/packages/domain/catalog/providers/salesforce/index.ts
index c95a1ab4..644fdb12 100644
--- a/packages/domain/catalog/providers/salesforce/index.ts
+++ b/packages/domain/catalog/providers/salesforce/index.ts
@@ -1,2 +1,2 @@
-export * from "./mapper";
-export * from "./raw.types";
+export * from "./mapper.js";
+export * from "./raw.types.js";
diff --git a/packages/domain/catalog/providers/salesforce/mapper.ts b/packages/domain/catalog/providers/salesforce/mapper.ts
index c2249024..3fc6cdc7 100644
--- a/packages/domain/catalog/providers/salesforce/mapper.ts
+++ b/packages/domain/catalog/providers/salesforce/mapper.ts
@@ -12,16 +12,16 @@ import type {
   SimCatalogProduct,
   SimActivationFeeCatalogItem,
   VpnCatalogProduct,
-} from "../../contract";
+} from "../../contract.js";
 import type {
   SalesforceProduct2WithPricebookEntries,
   SalesforcePricebookEntryRecord,
-} from "./raw.types";
+} from "./raw.types.js";
 import {
   enrichInternetPlanMetadata,
   inferAddonTypeFromSku,
   inferInstallationTermFromSku,
-} from "../../utils";
+} from "../../utils.js";
 
 // ============================================================================
 // Tier Templates (Hardcoded Product Metadata)
diff --git a/packages/domain/catalog/providers/whmcs/index.ts b/packages/domain/catalog/providers/whmcs/index.ts
index f8bb8eb7..3f41fad4 100644
--- a/packages/domain/catalog/providers/whmcs/index.ts
+++ b/packages/domain/catalog/providers/whmcs/index.ts
@@ -1,2 +1,2 @@
-export * from "./raw.types";
+export * from "./raw.types.js";
 
diff --git a/packages/domain/catalog/providers/whmcs/mapper.ts b/packages/domain/catalog/providers/whmcs/mapper.ts
index cfac6baf..978cf053 100644
--- a/packages/domain/catalog/providers/whmcs/mapper.ts
+++ b/packages/domain/catalog/providers/whmcs/mapper.ts
@@ -1,8 +1,8 @@
-import { parseAmount } from "../../../providers/whmcs/utils";
+import { parseAmount } from "../../../providers/whmcs/utils.js";
 import {
   whmcsCatalogProductListResponseSchema,
   type WhmcsCatalogProductListResponse,
-} from "./raw.types";
+} from "./raw.types.js";
 
 export interface WhmcsCatalogPricing {
   currency: string;
diff --git a/packages/domain/catalog/utils.ts b/packages/domain/catalog/utils.ts
index 14edb7c3..7f5c4f06 100644
--- a/packages/domain/catalog/utils.ts
+++ b/packages/domain/catalog/utils.ts
@@ -9,8 +9,8 @@ import {
   type VpnCatalogCollection,
   type InternetPlanTemplate,
   type CatalogProductBase,
-} from "./schema";
-import type { CatalogPriceInfo } from "./contract";
+} from "./schema.js";
+import type { CatalogPriceInfo } from "./contract.js";
 
 /**
  * Empty catalog defaults shared by portal and BFF.
diff --git a/packages/domain/common/index.ts b/packages/domain/common/index.ts
index e1cb8bc1..52eeb177 100644
--- a/packages/domain/common/index.ts
+++ b/packages/domain/common/index.ts
@@ -4,15 +4,15 @@
  * Shared types and utilities used across all domains.
  */
 
-export * from "./types";
-export * from "./schema";
-export * from "./validation";
-export * from "./errors";
+export * from "./types.js";
+export * from "./schema.js";
+export * from "./validation.js";
+export * from "./errors.js";
 
 // Common provider types (generic wrappers used across domains)
-export * as CommonProviders from "./providers/index";
+export * as CommonProviders from "./providers/index.js";
 
 // Re-export provider types for convenience
-export type { WhmcsResponse, WhmcsErrorResponse } from "./providers/whmcs";
-export type { SalesforceResponse } from "./providers/salesforce";
+export type { WhmcsResponse, WhmcsErrorResponse } from "./providers/whmcs.js";
+export type { SalesforceResponse } from "./providers/salesforce.js";
 
diff --git a/packages/domain/common/providers/index.ts b/packages/domain/common/providers/index.ts
index 66cf0a19..5d6247fe 100644
--- a/packages/domain/common/providers/index.ts
+++ b/packages/domain/common/providers/index.ts
@@ -4,5 +4,5 @@
  * Generic provider-specific response structures used across multiple domains.
  */
 
-export * as Whmcs from "./whmcs";
-export * as Salesforce from "./salesforce/index";
+export * as Whmcs from "./whmcs.js";
+export * as Salesforce from "./salesforce/index.js";
diff --git a/packages/domain/common/providers/salesforce/index.ts b/packages/domain/common/providers/salesforce/index.ts
index f8bb8eb7..3f41fad4 100644
--- a/packages/domain/common/providers/salesforce/index.ts
+++ b/packages/domain/common/providers/salesforce/index.ts
@@ -1,2 +1,2 @@
-export * from "./raw.types";
+export * from "./raw.types.js";
 
diff --git a/packages/domain/customer/contract.ts b/packages/domain/customer/contract.ts
index 2fd7f7e1..b85b4826 100644
--- a/packages/domain/customer/contract.ts
+++ b/packages/domain/customer/contract.ts
@@ -52,4 +52,4 @@ export type {
   UserRole,
   Address,
   AddressFormData,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/customer/index.ts b/packages/domain/customer/index.ts
index 481b748e..3fabd9aa 100644
--- a/packages/domain/customer/index.ts
+++ b/packages/domain/customer/index.ts
@@ -15,7 +15,7 @@
 // Constants
 // ============================================================================
 
-export { USER_ROLE, type UserRoleValue } from "./contract";
+export { USER_ROLE, type UserRoleValue } from "./contract.js";
 
 // ============================================================================
 // Domain Types (Clean Names - Public API)
@@ -32,7 +32,7 @@ export type {
   UserProfile,    // Alias for User
   AuthenticatedUser, // Alias for authenticated user
   WhmcsClient,    // Provider-normalized WHMCS client shape
-} from "./schema";
+} from "./schema.js";
 
 // ============================================================================
 // Schemas
@@ -50,7 +50,7 @@ export {
   combineToUser,        // Domain helper: UserAuth + WhmcsClient → User
   addressFormToRequest,
   profileFormToRequest,
-} from "./schema";
+} from "./schema.js";
 
 // ============================================================================
 // Provider Namespace
@@ -64,7 +64,7 @@ export {
  * - Providers.Whmcs.transformWhmcsClientResponse()
  * - Providers.Portal.mapPrismaUserToUserAuth()
  */
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // ============================================================================
 // Provider Raw Response Types (Selective Exports)
@@ -84,7 +84,7 @@ export type {
   WhmcsAddClientResponse,
   WhmcsValidateLoginResponse,
   WhmcsSsoResponse,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
 
 // ============================================================================
 // Provider-Specific Types (For Integrations)
@@ -97,4 +97,4 @@ export type {
 export type {
   SalesforceAccountFieldMap,
   SalesforceAccountRecord,
-} from "./contract";
+} from "./contract.js";
diff --git a/packages/domain/customer/providers/index.ts b/packages/domain/customer/providers/index.ts
index 9418f559..5f2ba815 100644
--- a/packages/domain/customer/providers/index.ts
+++ b/packages/domain/customer/providers/index.ts
@@ -6,5 +6,5 @@
  * - Whmcs: WHMCS API → WhmcsClient
  */
 
-export * as Portal from "./portal/index";
-export * as Whmcs from "./whmcs/index";
+export * as Portal from "./portal/index.js";
+export * as Whmcs from "./whmcs/index.js";
diff --git a/packages/domain/customer/providers/portal/index.ts b/packages/domain/customer/providers/portal/index.ts
index ab0d3e8c..0187c163 100644
--- a/packages/domain/customer/providers/portal/index.ts
+++ b/packages/domain/customer/providers/portal/index.ts
@@ -4,6 +4,6 @@
  * Handles mapping from Prisma (portal database) to UserAuth domain type
  */
 
-export * from "./mapper";
-export * from "./types";
+export * from "./mapper.js";
+export * from "./types.js";
 
diff --git a/packages/domain/customer/providers/portal/mapper.ts b/packages/domain/customer/providers/portal/mapper.ts
index d7df7193..d55fca00 100644
--- a/packages/domain/customer/providers/portal/mapper.ts
+++ b/packages/domain/customer/providers/portal/mapper.ts
@@ -4,9 +4,9 @@
  * Maps Prisma user data to UserAuth domain type using schema validation
  */
 
-import { userAuthSchema } from "../../schema";
-import type { PrismaUserRaw } from "./types";
-import type { UserAuth } from "../../schema";
+import { userAuthSchema } from "../../schema.js";
+import type { PrismaUserRaw } from "./types.js";
+import type { UserAuth } from "../../schema.js";
 
 /**
  * Maps raw Prisma user data to UserAuth domain type
diff --git a/packages/domain/customer/providers/portal/types.ts b/packages/domain/customer/providers/portal/types.ts
index e9266b0e..b60d1ef6 100644
--- a/packages/domain/customer/providers/portal/types.ts
+++ b/packages/domain/customer/providers/portal/types.ts
@@ -5,7 +5,7 @@
  * Domain doesn't depend on @prisma/client directly.
  */
 
-import type { UserRole } from "../../schema";
+import type { UserRole } from "../../schema.js";
 
 /**
  * Raw Prisma user data from portal database
diff --git a/packages/domain/customer/providers/whmcs/index.ts b/packages/domain/customer/providers/whmcs/index.ts
index 6c5bb00b..c1c27f2c 100644
--- a/packages/domain/customer/providers/whmcs/index.ts
+++ b/packages/domain/customer/providers/whmcs/index.ts
@@ -5,9 +5,9 @@
  * Exports transformation functions and raw API types (request/response).
  */
 
-export * from "./mapper";
-export * from "./raw.types";
-export { getCustomFieldValue, getCustomFieldsMap } from "../../../providers/whmcs/utils";
+export * from "./mapper.js";
+export * from "./raw.types.js";
+export { getCustomFieldValue, getCustomFieldsMap } from "../../../providers/whmcs/utils.js";
 
 // Re-export domain types for provider namespace convenience
-export type { WhmcsClient, EmailPreferences, SubUser, Stats } from "../../schema";
+export type { WhmcsClient, EmailPreferences, SubUser, Stats } from "../../schema.js";
diff --git a/packages/domain/customer/providers/whmcs/mapper.ts b/packages/domain/customer/providers/whmcs/mapper.ts
index 8e7f17a3..85802a6e 100644
--- a/packages/domain/customer/providers/whmcs/mapper.ts
+++ b/packages/domain/customer/providers/whmcs/mapper.ts
@@ -7,14 +7,14 @@
 
 import { z } from "zod";
 
-import type { WhmcsClient, Address } from "../../schema";
-import { whmcsClientSchema, addressSchema } from "../../schema";
+import type { WhmcsClient, Address } from "../../schema.js";
+import { whmcsClientSchema, addressSchema } from "../../schema.js";
 import {
   whmcsClientSchema as whmcsRawClientSchema,
   whmcsClientResponseSchema,
   type WhmcsClient as WhmcsRawClient,
   type WhmcsClientResponse,
-} from "./raw.types";
+} from "./raw.types.js";
 
 /**
  * Parse and validate WHMCS client response
diff --git a/packages/domain/customer/schema.ts b/packages/domain/customer/schema.ts
index 711fef23..546e66b3 100644
--- a/packages/domain/customer/schema.ts
+++ b/packages/domain/customer/schema.ts
@@ -12,8 +12,8 @@
 
 import { z } from "zod";
 
-import { countryCodeSchema } from "../common/schema";
-import { whmcsClientSchema as whmcsRawClientSchema, whmcsCustomFieldSchema } from "./providers/whmcs/raw.types";
+import { countryCodeSchema } from "../common/schema.js";
+import { whmcsClientSchema as whmcsRawClientSchema, whmcsCustomFieldSchema } from "./providers/whmcs/raw.types.js";
 
 // ============================================================================
 // Helper Schemas
diff --git a/packages/domain/dashboard/contract.ts b/packages/domain/dashboard/contract.ts
index 61816ae2..ef5d0ea8 100644
--- a/packages/domain/dashboard/contract.ts
+++ b/packages/domain/dashboard/contract.ts
@@ -9,7 +9,7 @@ import {
   activityFilterSchema,
   activityFilterConfigSchema,
   dashboardSummaryResponseSchema,
-} from "./schema";
+} from "./schema.js";
 
 export type ActivityType = z.infer<typeof activityTypeSchema>;
 export type Activity = z.infer<typeof activitySchema>;
diff --git a/packages/domain/dashboard/index.ts b/packages/domain/dashboard/index.ts
index 293473c2..4cfe4497 100644
--- a/packages/domain/dashboard/index.ts
+++ b/packages/domain/dashboard/index.ts
@@ -2,6 +2,6 @@
  * Dashboard Domain
  */
 
-export * from "./contract";
-export * from "./schema";
-export * from "./utils";
+export * from "./contract.js";
+export * from "./schema.js";
+export * from "./utils.js";
diff --git a/packages/domain/dashboard/schema.ts b/packages/domain/dashboard/schema.ts
index f1fb340a..790993d5 100644
--- a/packages/domain/dashboard/schema.ts
+++ b/packages/domain/dashboard/schema.ts
@@ -1,5 +1,5 @@
 import { z } from "zod";
-import { invoiceSchema } from "../billing/schema";
+import { invoiceSchema } from "../billing/schema.js";
 
 export const activityTypeSchema = z.enum([
   "invoice_created",
diff --git a/packages/domain/dashboard/utils.ts b/packages/domain/dashboard/utils.ts
index 99ef49bb..93c2c925 100644
--- a/packages/domain/dashboard/utils.ts
+++ b/packages/domain/dashboard/utils.ts
@@ -3,7 +3,7 @@
  * Business logic for dashboard activities and task generation
  */
 
-import type { Activity, ActivityFilter, ActivityFilterConfig, ActivityType } from "./contract";
+import type { Activity, ActivityFilter, ActivityFilterConfig, ActivityType } from "./contract.js";
 
 /**
  * Activity filter configurations
diff --git a/packages/domain/index.ts b/packages/domain/index.ts
index 01c8a70d..ad70d807 100644
--- a/packages/domain/index.ts
+++ b/packages/domain/index.ts
@@ -4,16 +4,16 @@
  */
 
 // Re-export domain modules
-export * as Billing from "./billing/index";
-export * as Subscriptions from "./subscriptions/index";
-export * as Payments from "./payments/index";
-export * as Sim from "./sim/index";
-export * as Support from "./support/index";
-export * as Orders from "./orders/index";
-export * as Catalog from "./catalog/index";
-export * as Common from "./common/index";
-export * as Toolkit from "./toolkit/index";
-export * as Auth from "./auth/index";
-export * as Customer from "./customer/index";
-export * as Mappings from "./mappings/index";
-export * as Dashboard from "./dashboard/index";
+export * as Billing from "./billing/index.js";
+export * as Subscriptions from "./subscriptions/index.js";
+export * as Payments from "./payments/index.js";
+export * as Sim from "./sim/index.js";
+export * as Support from "./support/index.js";
+export * as Orders from "./orders/index.js";
+export * as Catalog from "./catalog/index.js";
+export * as Common from "./common/index.js";
+export * as Toolkit from "./toolkit/index.js";
+export * as Auth from "./auth/index.js";
+export * as Customer from "./customer/index.js";
+export * as Mappings from "./mappings/index.js";
+export * as Dashboard from "./dashboard/index.js";
diff --git a/packages/domain/mappings/contract.ts b/packages/domain/mappings/contract.ts
index 9bf0b6f1..54cf8089 100644
--- a/packages/domain/mappings/contract.ts
+++ b/packages/domain/mappings/contract.ts
@@ -4,7 +4,7 @@
  * Normalized types for mapping portal users to external systems.
  */
 
-import type { IsoDateTimeString } from "../common/types";
+import type { IsoDateTimeString } from "../common/types.js";
 
 export interface UserIdMapping {
   id: string;
diff --git a/packages/domain/mappings/index.ts b/packages/domain/mappings/index.ts
index 3a6a9624..83e253c9 100644
--- a/packages/domain/mappings/index.ts
+++ b/packages/domain/mappings/index.ts
@@ -2,9 +2,9 @@
  * ID Mapping Domain
  */
 
-export * from "./contract";
-export * from "./schema";
-export * from "./validation";
+export * from "./contract.js";
+export * from "./schema.js";
+export * from "./validation.js";
 
 // Re-export types for convenience
 export type {
@@ -12,5 +12,5 @@ export type {
   MappingStats,
   BulkMappingOperation,
   BulkMappingResult,
-} from "./schema";
-export type { MappingValidationResult } from "./contract";
+} from "./schema.js";
+export type { MappingValidationResult } from "./contract.js";
diff --git a/packages/domain/mappings/schema.ts b/packages/domain/mappings/schema.ts
index 47650c0f..30c6defc 100644
--- a/packages/domain/mappings/schema.ts
+++ b/packages/domain/mappings/schema.ts
@@ -7,7 +7,7 @@ import type {
   CreateMappingRequest,
   UpdateMappingRequest,
   UserIdMapping,
-} from "./contract";
+} from "./contract.js";
 
 export const createMappingRequestSchema: z.ZodType<CreateMappingRequest> = z.object({
   userId: z.string().uuid(),
diff --git a/packages/domain/mappings/validation.ts b/packages/domain/mappings/validation.ts
index 52412ebe..4160091e 100644
--- a/packages/domain/mappings/validation.ts
+++ b/packages/domain/mappings/validation.ts
@@ -10,13 +10,13 @@ import {
   createMappingRequestSchema,
   updateMappingRequestSchema,
   userIdMappingSchema,
-} from "./schema";
+} from "./schema.js";
 import type {
   CreateMappingRequest,
   UpdateMappingRequest,
   UserIdMapping,
   MappingValidationResult,
-} from "./contract";
+} from "./contract.js";
 
 /**
  * Check if a mapping request has optional Salesforce account ID
diff --git a/packages/domain/orders/contract.ts b/packages/domain/orders/contract.ts
index 7272cda6..35243f77 100644
--- a/packages/domain/orders/contract.ts
+++ b/packages/domain/orders/contract.ts
@@ -5,11 +5,11 @@
  * Validated types are derived from schemas (see schema.ts).
  */
 
-import type { SalesforceProductFieldMap } from "../catalog/contract";
-import type { SalesforceAccountFieldMap } from "../customer/index";
-import type { UserIdMapping } from "../mappings/contract";
-import type { SalesforceOrderRecord } from "./providers/salesforce/raw.types";
-import type { OrderConfigurations } from "./schema";
+import type { SalesforceProductFieldMap } from "../catalog/contract.js";
+import type { SalesforceAccountFieldMap } from "../customer/index.js";
+import type { UserIdMapping } from "../mappings/contract.js";
+import type { SalesforceOrderRecord } from "./providers/salesforce/raw.types.js";
+import type { OrderConfigurations } from "./schema.js";
 
 // ============================================================================
 // Order Type Constants
@@ -205,4 +205,4 @@ export type {
   CreateOrderRequest,
   OrderBusinessValidation,
   SfOrderIdParam,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/orders/helpers.ts b/packages/domain/orders/helpers.ts
index f2ead6d6..68b024b7 100644
--- a/packages/domain/orders/helpers.ts
+++ b/packages/domain/orders/helpers.ts
@@ -8,11 +8,11 @@ import {
   type OrderDisplayItemCategory,
   type OrderDisplayItemCharge,
   type OrderDisplayItemChargeKind,
-} from "./schema";
-import { ORDER_TYPE } from "./contract";
-import type { CheckoutTotals } from "./contract";
-import type { SimConfigureFormData } from "../sim";
-import type { WhmcsOrderItem } from "./providers/whmcs/raw.types";
+} from "./schema.js";
+import { ORDER_TYPE } from "./contract.js";
+import type { CheckoutTotals } from "./contract.js";
+import type { SimConfigureFormData } from "../sim/index.js";
+import type { WhmcsOrderItem } from "./providers/whmcs/raw.types.js";
 
 export interface BuildSimOrderConfigurationsOptions {
   /**
diff --git a/packages/domain/orders/index.ts b/packages/domain/orders/index.ts
index ecc88fd6..2e50b097 100644
--- a/packages/domain/orders/index.ts
+++ b/packages/domain/orders/index.ts
@@ -30,17 +30,17 @@ export {
   type AccessModeValue,
   ORDER_FULFILLMENT_ERROR_CODE,
   type OrderFulfillmentErrorCode,
-} from "./contract";
+} from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Validation (extended business rules)
-export * from "./validation";
+export * from "./validation.js";
 
 // Utilities
-export * from "./utils";
-export * from "./events";
+export * from "./utils.js";
+export * from "./events.js";
 export {
   buildSimOrderConfigurations,
   normalizeBillingCycle,
@@ -58,7 +58,7 @@ export {
   getOrderServiceCategory,
   calculateOrderTotals,
   formatScheduledDate,
-} from "./helpers";
+} from "./helpers.js";
 // Re-export types for convenience
 export type {
   // Order item types
@@ -79,12 +79,12 @@ export type {
   OrderDisplayItemCategory,
   OrderDisplayItemCharge,
   OrderDisplayItemChargeKind,
-} from './schema';
+} from './schema.js';
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider types for convenience
-export * from "./providers/whmcs/raw.types";
-export * from "./providers/salesforce/raw.types";
-export * from "./providers/salesforce/field-map";
+export * from "./providers/whmcs/raw.types.js";
+export * from "./providers/salesforce/raw.types.js";
+export * from "./providers/salesforce/field-map.js";
diff --git a/packages/domain/orders/providers/index.ts b/packages/domain/orders/providers/index.ts
index cfcb8022..13ba79ad 100644
--- a/packages/domain/orders/providers/index.ts
+++ b/packages/domain/orders/providers/index.ts
@@ -2,11 +2,11 @@
  * Orders Domain - Providers
  */
 
-import * as WhmcsMapper from "./whmcs/mapper";
-import * as WhmcsRaw from "./whmcs/raw.types";
-import * as SalesforceFieldMap from "./salesforce/field-map";
-import * as SalesforceMapper from "./salesforce/mapper";
-import * as SalesforceRaw from "./salesforce/raw.types";
+import * as WhmcsMapper from "./whmcs/mapper.js";
+import * as WhmcsRaw from "./whmcs/raw.types.js";
+import * as SalesforceFieldMap from "./salesforce/field-map.js";
+import * as SalesforceMapper from "./salesforce/mapper.js";
+import * as SalesforceRaw from "./salesforce/raw.types.js";
 
 export const Whmcs = {
   ...WhmcsMapper,
@@ -27,8 +27,8 @@ export {
   SalesforceMapper,
   SalesforceRaw,
 };
-export * from "./whmcs/mapper";
-export * from "./whmcs/raw.types";
-export * from "./salesforce/mapper";
-export * from "./salesforce/raw.types";
-export * from "./salesforce/field-map";
+export * from "./whmcs/mapper.js";
+export * from "./whmcs/raw.types.js";
+export * from "./salesforce/mapper.js";
+export * from "./salesforce/raw.types.js";
+export * from "./salesforce/field-map.js";
diff --git a/packages/domain/orders/providers/salesforce/field-map.ts b/packages/domain/orders/providers/salesforce/field-map.ts
index 35314622..72aa7a19 100644
--- a/packages/domain/orders/providers/salesforce/field-map.ts
+++ b/packages/domain/orders/providers/salesforce/field-map.ts
@@ -1,8 +1,8 @@
-import type { SalesforceProduct2WithPricebookEntries } from "../../../catalog/providers/salesforce/raw.types";
+import type { SalesforceProduct2WithPricebookEntries } from "../../../catalog/providers/salesforce/raw.types.js";
 import type {
   SalesforceOrderItemRecord,
   SalesforceOrderRecord,
-} from "./raw.types";
+} from "./raw.types.js";
 
 export interface SalesforceOrderFieldMap {
   order: {
diff --git a/packages/domain/orders/providers/salesforce/index.ts b/packages/domain/orders/providers/salesforce/index.ts
index 2dd11e02..fa8002ef 100644
--- a/packages/domain/orders/providers/salesforce/index.ts
+++ b/packages/domain/orders/providers/salesforce/index.ts
@@ -1,2 +1,2 @@
-export * from "./raw.types";
-export * from "./mapper";
+export * from "./raw.types.js";
+export * from "./mapper.js";
diff --git a/packages/domain/orders/providers/salesforce/mapper.ts b/packages/domain/orders/providers/salesforce/mapper.ts
index 61bdedad..3e558b34 100644
--- a/packages/domain/orders/providers/salesforce/mapper.ts
+++ b/packages/domain/orders/providers/salesforce/mapper.ts
@@ -9,21 +9,21 @@ import type {
   OrderItemDetails,
   OrderItemSummary,
   OrderSummary,
-} from "../../contract";
-import { normalizeBillingCycle } from "../../helpers";
-import { orderDetailsSchema, orderSummarySchema, orderItemDetailsSchema } from "../../schema";
+} from "../../contract.js";
+import { normalizeBillingCycle } from "../../helpers.js";
+import { orderDetailsSchema, orderSummarySchema, orderItemDetailsSchema } from "../../schema.js";
 import type {
   SalesforceProduct2WithPricebookEntries,
   SalesforcePricebookEntryRecord,
-} from "../../../catalog/providers/salesforce/raw.types";
+} from "../../../catalog/providers/salesforce/raw.types.js";
 import {
   defaultSalesforceOrderFieldMap,
   type SalesforceOrderFieldMap,
-} from "./field-map";
+} from "./field-map.js";
 import type {
   SalesforceOrderItemRecord,
   SalesforceOrderRecord,
-} from "./raw.types";
+} from "./raw.types.js";
 
 /**
  * Helper function to get sort priority for item class
diff --git a/packages/domain/orders/providers/whmcs/index.ts b/packages/domain/orders/providers/whmcs/index.ts
index c95a1ab4..644fdb12 100644
--- a/packages/domain/orders/providers/whmcs/index.ts
+++ b/packages/domain/orders/providers/whmcs/index.ts
@@ -1,2 +1,2 @@
-export * from "./mapper";
-export * from "./raw.types";
+export * from "./mapper.js";
+export * from "./raw.types.js";
diff --git a/packages/domain/orders/providers/whmcs/mapper.ts b/packages/domain/orders/providers/whmcs/mapper.ts
index 8784eafd..72806778 100644
--- a/packages/domain/orders/providers/whmcs/mapper.ts
+++ b/packages/domain/orders/providers/whmcs/mapper.ts
@@ -4,13 +4,13 @@
  * Transforms normalized order data to WHMCS API format.
  */
 
-import type { OrderDetails, OrderItemDetails } from "../../contract";
-import { normalizeBillingCycle } from "../../helpers";
+import type { OrderDetails, OrderItemDetails } from "../../contract.js";
+import { normalizeBillingCycle } from "../../helpers.js";
 import {
   type WhmcsOrderItem,
   type WhmcsAddOrderParams,
   type WhmcsAddOrderPayload,
-} from "./raw.types";
+} from "./raw.types.js";
 
 export interface OrderItemMappingResult {
   whmcsItems: WhmcsOrderItem[];
diff --git a/packages/domain/orders/schema.ts b/packages/domain/orders/schema.ts
index bb5dfdab..b2db9552 100644
--- a/packages/domain/orders/schema.ts
+++ b/packages/domain/orders/schema.ts
@@ -5,7 +5,7 @@
  */
 
 import { z } from "zod";
-import { apiSuccessResponseSchema } from "../common";
+import { apiSuccessResponseSchema } from "../common/index.js";
 
 // ============================================================================
 // Enum Value Arrays (for Zod schemas)
diff --git a/packages/domain/orders/utils.ts b/packages/domain/orders/utils.ts
index 6895338b..7445e747 100644
--- a/packages/domain/orders/utils.ts
+++ b/packages/domain/orders/utils.ts
@@ -4,8 +4,8 @@ import {
   type OrderConfigurations,
   type CreateOrderRequest,
   type OrderSelections,
-} from "./schema";
-import { ORDER_TYPE, type CheckoutCart, type OrderTypeValue } from "./contract";
+} from "./schema.js";
+import { ORDER_TYPE, type CheckoutCart, type OrderTypeValue } from "./contract.js";
 
 export function buildOrderConfigurations(selections: OrderSelections): OrderConfigurations {
   const normalizedSelections = orderSelectionsSchema.parse(selections);
diff --git a/packages/domain/orders/validation.ts b/packages/domain/orders/validation.ts
index 90b64714..52816849 100644
--- a/packages/domain/orders/validation.ts
+++ b/packages/domain/orders/validation.ts
@@ -6,7 +6,7 @@
  */
 
 import { z } from "zod";
-import { orderBusinessValidationSchema } from "./schema";
+import { orderBusinessValidationSchema } from "./schema.js";
 
 // ============================================================================
 // SKU Business Rules Helpers
diff --git a/packages/domain/payments/contract.ts b/packages/domain/payments/contract.ts
index 75319d37..57e8f482 100644
--- a/packages/domain/payments/contract.ts
+++ b/packages/domain/payments/contract.ts
@@ -53,4 +53,4 @@ export type {
   PaymentGatewayType,
   PaymentGateway,
   PaymentGatewayList,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/payments/index.ts b/packages/domain/payments/index.ts
index b45aa5ae..76ba14ed 100644
--- a/packages/domain/payments/index.ts
+++ b/packages/domain/payments/index.ts
@@ -7,10 +7,10 @@
  */
 
 // Constants
-export { PAYMENT_METHOD_TYPE, PAYMENT_GATEWAY_TYPE, type InvoicePaymentLink } from "./contract";
+export { PAYMENT_METHOD_TYPE, PAYMENT_GATEWAY_TYPE, type InvoicePaymentLink } from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Re-export types for convenience
 export type {
@@ -20,10 +20,10 @@ export type {
   PaymentGatewayType,
   PaymentGateway,
   PaymentGatewayList,
-} from './schema';
+} from './schema.js';
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider raw types (request and response)
 export type {
@@ -34,4 +34,4 @@ export type {
   WhmcsPaymentMethodListResponse,
   WhmcsPaymentGateway,
   WhmcsPaymentGatewayListResponse,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
diff --git a/packages/domain/payments/providers/index.ts b/packages/domain/payments/providers/index.ts
index 507ead52..aa066ccc 100644
--- a/packages/domain/payments/providers/index.ts
+++ b/packages/domain/payments/providers/index.ts
@@ -2,8 +2,8 @@
  * Payments Domain - Providers
  */
 
-import * as WhmcsMapper from "./whmcs/mapper";
-import * as WhmcsRaw from "./whmcs/raw.types";
+import * as WhmcsMapper from "./whmcs/mapper.js";
+import * as WhmcsRaw from "./whmcs/raw.types.js";
 
 export const Whmcs = {
   ...WhmcsMapper,
@@ -12,5 +12,5 @@ export const Whmcs = {
 };
 
 export { WhmcsMapper, WhmcsRaw };
-export * from "./whmcs/mapper";
-export * from "./whmcs/raw.types";
+export * from "./whmcs/mapper.js";
+export * from "./whmcs/raw.types.js";
diff --git a/packages/domain/payments/providers/whmcs/index.ts b/packages/domain/payments/providers/whmcs/index.ts
index c95a1ab4..644fdb12 100644
--- a/packages/domain/payments/providers/whmcs/index.ts
+++ b/packages/domain/payments/providers/whmcs/index.ts
@@ -1,2 +1,2 @@
-export * from "./mapper";
-export * from "./raw.types";
+export * from "./mapper.js";
+export * from "./raw.types.js";
diff --git a/packages/domain/payments/providers/whmcs/mapper.ts b/packages/domain/payments/providers/whmcs/mapper.ts
index 8c6a8612..d037b26f 100644
--- a/packages/domain/payments/providers/whmcs/mapper.ts
+++ b/packages/domain/payments/providers/whmcs/mapper.ts
@@ -2,14 +2,14 @@
  * WHMCS Payments Provider - Mapper
  */
 
-import type { PaymentMethod, PaymentGateway } from "../../contract";
-import { paymentMethodSchema, paymentGatewaySchema } from "../../schema";
+import type { PaymentMethod, PaymentGateway } from "../../contract.js";
+import { paymentMethodSchema, paymentGatewaySchema } from "../../schema.js";
 import {
   type WhmcsPaymentMethodRaw,
   type WhmcsPaymentGatewayRaw,
   whmcsPaymentMethodRawSchema,
   whmcsPaymentGatewayRawSchema,
-} from "./raw.types";
+} from "./raw.types.js";
 
 const PAYMENT_TYPE_MAP: Record<string, PaymentMethod["type"]> = {
   creditcard: "CreditCard",
diff --git a/packages/domain/providers/index.ts b/packages/domain/providers/index.ts
index ca7bf5d1..70387966 100644
--- a/packages/domain/providers/index.ts
+++ b/packages/domain/providers/index.ts
@@ -3,5 +3,5 @@
  * Re-exports shared provider utilities
  */
 
-export * as Whmcs from "./whmcs";
+export * as Whmcs from "./whmcs/index.js";
 
diff --git a/packages/domain/providers/whmcs/index.ts b/packages/domain/providers/whmcs/index.ts
index 52fb8c23..ebe42dc1 100644
--- a/packages/domain/providers/whmcs/index.ts
+++ b/packages/domain/providers/whmcs/index.ts
@@ -3,5 +3,5 @@
  * Re-exports shared WHMCS provider utilities
  */
 
-export * from "./utils";
+export * from "./utils.js";
 
diff --git a/packages/domain/sim/contract.ts b/packages/domain/sim/contract.ts
index c00061c0..0111a874 100644
--- a/packages/domain/sim/contract.ts
+++ b/packages/domain/sim/contract.ts
@@ -64,4 +64,4 @@ export type {
   SimOrderActivationRequest,
   SimOrderActivationMnp,
   SimOrderActivationAddons,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/sim/helpers.ts b/packages/domain/sim/helpers.ts
index 9f4b97c6..2181d7a9 100644
--- a/packages/domain/sim/helpers.ts
+++ b/packages/domain/sim/helpers.ts
@@ -1,5 +1,5 @@
-import { SIM_PLAN_CODES, SIM_PLAN_LABELS, SIM_STATUS } from "./contract";
-import type { SimStatus, SimFeaturesUpdateRequest } from "./schema";
+import { SIM_PLAN_CODES, SIM_PLAN_LABELS, SIM_STATUS } from "./contract.js";
+import type { SimStatus, SimFeaturesUpdateRequest } from "./schema.js";
 
 export function canManageActiveSim(status: SimStatus): boolean {
   return status === SIM_STATUS.ACTIVE;
diff --git a/packages/domain/sim/index.ts b/packages/domain/sim/index.ts
index 620886f9..7506ac24 100644
--- a/packages/domain/sim/index.ts
+++ b/packages/domain/sim/index.ts
@@ -7,14 +7,14 @@
  */
 
 // Constants
-export { SIM_STATUS, SIM_TYPE, SIM_PLAN_CODES, SIM_PLAN_LABELS } from "./contract";
+export { SIM_STATUS, SIM_TYPE, SIM_PLAN_CODES, SIM_PLAN_LABELS } from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
-export * from "./lifecycle";
+export * from "./schema.js";
+export * from "./lifecycle.js";
 
 // Validation functions
-export * from "./validation";
+export * from "./validation.js";
 export {
   canManageActiveSim,
   canReissueEsim,
@@ -24,7 +24,7 @@ export {
   SIM_PLAN_OPTIONS,
   getSimPlanLabel,
   buildSimFeaturesUpdatePayload,
-} from "./helpers";
+} from "./helpers.js";
 
 // Re-export types for convenience
 export type {
@@ -59,9 +59,9 @@ export type {
   SimTopUpPricing,
   SimTopUpPricingPreviewRequest,
   SimTopUpPricingPreviewResponse,
-} from './schema';
-export type { SimPlanCode } from "./contract";
-export type { SimPlanOption, SimFeatureToggleSnapshot } from "./helpers";
+} from './schema.js';
+export type { SimPlanCode } from "./contract.js";
+export type { SimPlanOption, SimFeatureToggleSnapshot } from "./helpers.js";
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
diff --git a/packages/domain/sim/providers/freebit/index.ts b/packages/domain/sim/providers/freebit/index.ts
index 3838aa5c..c6992c04 100644
--- a/packages/domain/sim/providers/freebit/index.ts
+++ b/packages/domain/sim/providers/freebit/index.ts
@@ -1,7 +1,7 @@
-import * as Mapper from "./mapper";
-import * as RawTypes from "./raw.types";
-import * as Requests from "./requests";
-import * as Utils from "./utils";
+import * as Mapper from "./mapper.js";
+import * as RawTypes from "./raw.types.js";
+import * as Requests from "./requests.js";
+import * as Utils from "./utils.js";
 
 export const schemas = {
   accountDetails: Requests.freebitAccountDetailsRequestSchema,
@@ -51,10 +51,10 @@ export type EsimAddAccountResponse = ReturnType<typeof Mapper.transformFreebitEs
 export type EsimActivationResponse = ReturnType<typeof Mapper.transformFreebitEsimActivationResponse>;
 export type AuthResponse = ReturnType<typeof Mapper.transformFreebitAuthResponse>;
 
-export * from "./mapper";
-export * from "./raw.types";
-export * from "./requests";
-export * from "./utils";
+export * from "./mapper.js";
+export * from "./raw.types.js";
+export * from "./requests.js";
+export * from "./utils.js";
 
 export const Freebit = {
   ...Mapper,
diff --git a/packages/domain/sim/providers/freebit/mapper.ts b/packages/domain/sim/providers/freebit/mapper.ts
index 053b3d64..fecf4383 100644
--- a/packages/domain/sim/providers/freebit/mapper.ts
+++ b/packages/domain/sim/providers/freebit/mapper.ts
@@ -2,8 +2,8 @@
  * Freebit SIM Provider - Mapper
  */
 
-import type { SimDetails, SimUsage, SimTopUpHistory, SimType, SimStatus } from "../../contract";
-import { simDetailsSchema, simUsageSchema, simTopUpHistorySchema } from "../../schema";
+import type { SimDetails, SimUsage, SimTopUpHistory, SimType, SimStatus } from "../../contract.js";
+import { simDetailsSchema, simUsageSchema, simTopUpHistorySchema } from "../../schema.js";
 import {
   type FreebitAccountDetailsRaw,
   type FreebitTrafficInfoRaw,
@@ -27,8 +27,8 @@ import {
   freebitCancelAccountRawSchema,
   freebitEsimReissueRawSchema,
   freebitEsimAddAccountRawSchema,
-} from "./raw.types";
-import { normalizeAccount } from "./utils";
+} from "./raw.types.js";
+import { normalizeAccount } from "./utils.js";
 
 function asString(value: unknown): string {
   if (typeof value === "string") return value;
diff --git a/packages/domain/sim/providers/index.ts b/packages/domain/sim/providers/index.ts
index f15ef235..a698aaa4 100644
--- a/packages/domain/sim/providers/index.ts
+++ b/packages/domain/sim/providers/index.ts
@@ -2,9 +2,9 @@
  * SIM Domain - Providers
  */
 
-import { Freebit as FreebitAggregated } from "./freebit/index";
-import * as FreebitModule from "./freebit/index";
+import { Freebit as FreebitAggregated } from "./freebit/index.js";
+import * as FreebitModule from "./freebit/index.js";
 
 export const Freebit = FreebitAggregated;
 export { FreebitModule };
-export * from "./freebit/index";
+export * from "./freebit/index.js";
diff --git a/packages/domain/sim/validation.ts b/packages/domain/sim/validation.ts
index 3c258035..173b851c 100644
--- a/packages/domain/sim/validation.ts
+++ b/packages/domain/sim/validation.ts
@@ -5,7 +5,7 @@
  * These functions contain no infrastructure dependencies.
  */
 
-import type { Subscription } from "../subscriptions/schema";
+import type { Subscription } from "../subscriptions/schema.js";
 
 /**
  * Check if a subscription is a SIM service
diff --git a/packages/domain/subscriptions/contract.ts b/packages/domain/subscriptions/contract.ts
index 996f0a30..f3f5d2fd 100644
--- a/packages/domain/subscriptions/contract.ts
+++ b/packages/domain/subscriptions/contract.ts
@@ -45,4 +45,4 @@ export type {
   SubscriptionList,
   SubscriptionQueryParams,
   SubscriptionQuery,
-} from './schema';
+} from './schema.js';
diff --git a/packages/domain/subscriptions/index.ts b/packages/domain/subscriptions/index.ts
index 86810593..31be33af 100644
--- a/packages/domain/subscriptions/index.ts
+++ b/packages/domain/subscriptions/index.ts
@@ -7,10 +7,10 @@
  */
 
 // Constants
-export { SUBSCRIPTION_STATUS, SUBSCRIPTION_CYCLE } from "./contract";
+export { SUBSCRIPTION_STATUS, SUBSCRIPTION_CYCLE } from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Re-export types for convenience
 export type {
@@ -23,10 +23,10 @@ export type {
   SubscriptionStats,
   SimActionResponse,
   SimPlanChangeResult,
-} from './schema';
+} from './schema.js';
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider raw types (request and response)
 export type {
@@ -34,8 +34,8 @@ export type {
   WhmcsGetClientsProductsParams,
   // Response types
   WhmcsProductListResponse,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
 
 export {
   whmcsProductListResponseSchema,
-} from "./providers/whmcs/raw.types";
+} from "./providers/whmcs/raw.types.js";
diff --git a/packages/domain/subscriptions/providers/index.ts b/packages/domain/subscriptions/providers/index.ts
index 6e242545..a1dd4436 100644
--- a/packages/domain/subscriptions/providers/index.ts
+++ b/packages/domain/subscriptions/providers/index.ts
@@ -2,8 +2,8 @@
  * Subscriptions Domain - Providers
  */
 
-import * as WhmcsMapper from "./whmcs/mapper";
-import * as WhmcsRaw from "./whmcs/raw.types";
+import * as WhmcsMapper from "./whmcs/mapper.js";
+import * as WhmcsRaw from "./whmcs/raw.types.js";
 
 export const Whmcs = {
   ...WhmcsMapper,
@@ -12,5 +12,5 @@ export const Whmcs = {
 };
 
 export { WhmcsMapper, WhmcsRaw };
-export * from "./whmcs/mapper";
-export * from "./whmcs/raw.types";
+export * from "./whmcs/mapper.js";
+export * from "./whmcs/raw.types.js";
diff --git a/packages/domain/subscriptions/providers/whmcs/index.ts b/packages/domain/subscriptions/providers/whmcs/index.ts
index c95a1ab4..644fdb12 100644
--- a/packages/domain/subscriptions/providers/whmcs/index.ts
+++ b/packages/domain/subscriptions/providers/whmcs/index.ts
@@ -1,2 +1,2 @@
-export * from "./mapper";
-export * from "./raw.types";
+export * from "./mapper.js";
+export * from "./raw.types.js";
diff --git a/packages/domain/subscriptions/providers/whmcs/mapper.ts b/packages/domain/subscriptions/providers/whmcs/mapper.ts
index 7c208035..825ef2f4 100644
--- a/packages/domain/subscriptions/providers/whmcs/mapper.ts
+++ b/packages/domain/subscriptions/providers/whmcs/mapper.ts
@@ -4,20 +4,20 @@
  * Transforms raw WHMCS product/service data into normalized subscription types.
  */
 
-import type { Subscription, SubscriptionStatus, SubscriptionCycle, SubscriptionList } from "../../contract";
-import { subscriptionSchema, subscriptionListSchema, subscriptionStatusSchema } from "../../schema";
+import type { Subscription, SubscriptionStatus, SubscriptionCycle, SubscriptionList } from "../../contract.js";
+import { subscriptionSchema, subscriptionListSchema, subscriptionStatusSchema } from "../../schema.js";
 import {
   type WhmcsProductRaw,
   whmcsProductRawSchema,
   whmcsCustomFieldsContainerSchema,
   whmcsProductListResponseSchema,
-} from "./raw.types";
+} from "./raw.types.js";
 import {
   parseAmount,
   formatDate,
   normalizeStatus,
   normalizeCycle,
-} from "../../../providers/whmcs/utils";
+} from "../../../providers/whmcs/utils.js";
 
 export interface TransformSubscriptionOptions {
   defaultCurrencyCode?: string;
diff --git a/packages/domain/support/index.ts b/packages/domain/support/index.ts
index b4a51315..cbe8be05 100644
--- a/packages/domain/support/index.ts
+++ b/packages/domain/support/index.ts
@@ -12,14 +12,14 @@ export {
   SUPPORT_CASE_PRIORITY,
   SUPPORT_CASE_CATEGORY,
   PORTAL_CASE_ORIGIN,
-} from "./contract";
+} from "./contract.js";
 
 // Schemas (includes derived types)
-export * from "./schema";
+export * from "./schema.js";
 
 // Provider adapters
-export * as Providers from "./providers/index";
+export * as Providers from "./providers/index.js";
 
 // Re-export provider types for convenience
-export * from "./providers/salesforce/raw.types";
-export * from "./providers/salesforce/mapper";
+export * from "./providers/salesforce/raw.types.js";
+export * from "./providers/salesforce/mapper.js";
diff --git a/packages/domain/support/providers/index.ts b/packages/domain/support/providers/index.ts
index fd193d44..b27585bd 100644
--- a/packages/domain/support/providers/index.ts
+++ b/packages/domain/support/providers/index.ts
@@ -2,8 +2,8 @@
  * Support Domain - Providers
  */
 
-import * as SalesforceMapper from "./salesforce/mapper";
-import * as SalesforceRaw from "./salesforce/raw.types";
+import * as SalesforceMapper from "./salesforce/mapper.js";
+import * as SalesforceRaw from "./salesforce/raw.types.js";
 
 export const Salesforce = {
   ...SalesforceMapper,
@@ -13,6 +13,6 @@ export const Salesforce = {
 };
 
 export { SalesforceMapper, SalesforceRaw };
-export * from "./salesforce/mapper";
-export * from "./salesforce/raw.types";
+export * from "./salesforce/mapper.js";
+export * from "./salesforce/raw.types.js";
 
diff --git a/packages/domain/support/providers/salesforce/index.ts b/packages/domain/support/providers/salesforce/index.ts
index 0b14f2b7..0f204088 100644
--- a/packages/domain/support/providers/salesforce/index.ts
+++ b/packages/domain/support/providers/salesforce/index.ts
@@ -2,6 +2,6 @@
  * Support Domain - Salesforce Provider
  */
 
-export * from "./raw.types";
-export * from "./mapper";
+export * from "./raw.types.js";
+export * from "./mapper.js";
 
diff --git a/packages/domain/support/providers/salesforce/mapper.ts b/packages/domain/support/providers/salesforce/mapper.ts
index 857a35ab..5930fe76 100644
--- a/packages/domain/support/providers/salesforce/mapper.ts
+++ b/packages/domain/support/providers/salesforce/mapper.ts
@@ -4,14 +4,14 @@
  * Transform functions to convert raw Salesforce Case records to domain types.
  */
 
-import { supportCaseSchema, type SupportCase } from "../../schema";
-import type { SalesforceCaseRecord } from "./raw.types";
+import { supportCaseSchema, type SupportCase } from "../../schema.js";
+import type { SalesforceCaseRecord } from "./raw.types.js";
 import {
   getStatusDisplayLabel,
   getPriorityDisplayLabel,
   SALESFORCE_CASE_STATUS,
   SALESFORCE_CASE_PRIORITY,
-} from "./raw.types";
+} from "./raw.types.js";
 
 // ============================================================================
 // Helper Functions
diff --git a/packages/domain/support/schema.ts b/packages/domain/support/schema.ts
index 42444ce6..86312b8f 100644
--- a/packages/domain/support/schema.ts
+++ b/packages/domain/support/schema.ts
@@ -3,7 +3,7 @@ import {
   SUPPORT_CASE_STATUS,
   SUPPORT_CASE_PRIORITY,
   SUPPORT_CASE_CATEGORY,
-} from "./contract";
+} from "./contract.js";
 
 /**
  * Portal status values (mapped from Salesforce Japanese API names)
diff --git a/packages/domain/toolkit/formatting/index.ts b/packages/domain/toolkit/formatting/index.ts
index 55c18748..54584657 100644
--- a/packages/domain/toolkit/formatting/index.ts
+++ b/packages/domain/toolkit/formatting/index.ts
@@ -4,8 +4,8 @@
  * Formatting utilities for currency, dates, phone numbers, etc.
  */
 
-export * from "./currency";
-export * from "./date";
-export * from "./phone";
-export * from "./text";
+export * from "./currency.js";
+export * from "./date.js";
+export * from "./phone.js";
+export * from "./text.js";
 
diff --git a/packages/domain/toolkit/index.ts b/packages/domain/toolkit/index.ts
index bf171701..3dde8d79 100644
--- a/packages/domain/toolkit/index.ts
+++ b/packages/domain/toolkit/index.ts
@@ -4,16 +4,16 @@
  * Utility functions and helpers used across all domain packages.
  */
 
-export * as Formatting from "./formatting/index";
-export * as Validation from "./validation/index";
-export * as Typing from "./typing/index";
+export * as Formatting from "./formatting/index.js";
+export * as Validation from "./validation/index.js";
+export * as Typing from "./typing/index.js";
 
 // Re-export commonly used utilities for convenience
-export { formatCurrency } from "./formatting/currency";
-export type { SupportedCurrency } from "./formatting/currency";
+export { formatCurrency } from "./formatting/currency.js";
+export type { SupportedCurrency } from "./formatting/currency.js";
 
 // Re-export AsyncState types and helpers
-export type { AsyncState } from "./typing/helpers";
+export type { AsyncState } from "./typing/helpers.js";
 export {
   createIdleState,
   createLoadingState,
@@ -23,5 +23,5 @@ export {
   isLoading,
   isSuccess,
   isError,
-} from "./typing/helpers";
+} from "./typing/helpers.js";
 
diff --git a/packages/domain/toolkit/typing/index.ts b/packages/domain/toolkit/typing/index.ts
index 20fed08a..4bb111cf 100644
--- a/packages/domain/toolkit/typing/index.ts
+++ b/packages/domain/toolkit/typing/index.ts
@@ -4,7 +4,7 @@
  * TypeScript type utilities and runtime type checking.
  */
 
-export * from "./guards";
-export * from "./assertions";
-export * from "./helpers";
+export * from "./guards.js";
+export * from "./assertions.js";
+export * from "./helpers.js";
 
diff --git a/packages/domain/toolkit/validation/index.ts b/packages/domain/toolkit/validation/index.ts
index da2ec409..8b5d8332 100644
--- a/packages/domain/toolkit/validation/index.ts
+++ b/packages/domain/toolkit/validation/index.ts
@@ -4,9 +4,9 @@
  * Validation utilities for common data types.
  */
 
-export * from "./email";
-export * from "./url";
-export * from "./string";
-export * from "./helpers";
+export * from "./email.js";
+export * from "./url.js";
+export * from "./string.js";
+export * from "./helpers.js";
 
 
diff --git a/packages/domain/tsconfig.json b/packages/domain/tsconfig.json
index fdbf3b7e..b7178b8f 100644
--- a/packages/domain/tsconfig.json
+++ b/packages/domain/tsconfig.json
@@ -5,9 +5,8 @@
     "outDir": "./dist",
     "rootDir": ".",
     "tsBuildInfoFile": "./dist/.tsbuildinfo",
-    "module": "ESNext",
-    "moduleResolution": "Bundler",
-    "verbatimModuleSyntax": false
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext"
   },
   "include": [
     "auth/**/*",
diff --git a/tsconfig.base.json b/tsconfig.base.json
index 39a9cf64..a5a27457 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -2,7 +2,7 @@
   "$schema": "https://json.schemastore.org/tsconfig",
   "compilerOptions": {
     "target": "ES2024",
-    "lib": ["ES2024"],
+    "lib": ["ESNext"],
     "strict": true,
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,