diff --git a/apps/bff/src/integrations/whmcs/cache/whmcs-cache.service.ts b/apps/bff/src/integrations/whmcs/cache/whmcs-cache.service.ts
index 51d081bc..5bc26706 100644
--- a/apps/bff/src/integrations/whmcs/cache/whmcs-cache.service.ts
+++ b/apps/bff/src/integrations/whmcs/cache/whmcs-cache.service.ts
@@ -5,7 +5,7 @@ import { CacheService } from "@bff/infra/cache/cache.service";
 import { Invoice, InvoiceList } from "@customer-portal/domain/billing";
 import { Subscription, SubscriptionList } from "@customer-portal/domain/subscriptions";
 import { PaymentMethodList, PaymentGatewayList } from "@customer-portal/domain/payments";
-import type { NormalizedWhmcsClient } from "../utils/whmcs-client.utils";
+import type { WhmcsClient } from "@customer-portal/domain/customer";
 
 export interface CacheOptions {
   ttl?: number;
@@ -148,15 +148,15 @@ export class WhmcsCacheService {
    * Get cached client data
    * Returns WhmcsClient (type inferred from domain)
    */
-  async getClientData(clientId: number): Promise<NormalizedWhmcsClient | null> {
+  async getClientData(clientId: number): Promise<WhmcsClient | null> {
     const key = this.buildClientKey(clientId);
-    return this.get<NormalizedWhmcsClient>(key, "client");
+    return this.get<WhmcsClient>(key, "client");
   }
 
   /**
    * Cache client data
    */
-  async setClientData(clientId: number, data: NormalizedWhmcsClient) {
+  async setClientData(clientId: number, data: WhmcsClient) {
     const key = this.buildClientKey(clientId);
     await this.set(key, data, "client", [`client:${clientId}`]);
   }
diff --git a/apps/bff/src/integrations/whmcs/services/whmcs-client.service.ts b/apps/bff/src/integrations/whmcs/services/whmcs-client.service.ts
index 99b1f830..74b5fe80 100644
--- a/apps/bff/src/integrations/whmcs/services/whmcs-client.service.ts
+++ b/apps/bff/src/integrations/whmcs/services/whmcs-client.service.ts
@@ -11,9 +11,9 @@ import type {
   WhmcsValidateLoginResponse,
 } from "@customer-portal/domain/customer";
 import {
-  normalizeWhmcsClientResponse,
-  type NormalizedWhmcsClient,
-} from "../utils/whmcs-client.utils";
+  Providers as CustomerProviders,
+  type WhmcsClient,
+} from "@customer-portal/domain/customer";
 
 @Injectable()
 export class WhmcsClientService {
@@ -56,7 +56,7 @@ export class WhmcsClientService {
    * Get client details by ID
    * Returns WhmcsClient (type inferred from domain mapper)
    */
-  async getClientDetails(clientId: number): Promise<NormalizedWhmcsClient> {
+  async getClientDetails(clientId: number): Promise<WhmcsClient> {
     try {
       // Try cache first
       const cached = await this.cacheService.getClientData(clientId);
@@ -75,11 +75,11 @@ export class WhmcsClientService {
         throw new NotFoundException(`Client ${clientId} not found`);
       }
 
-      const normalized = normalizeWhmcsClientResponse(response);
-      await this.cacheService.setClientData(normalized.id, normalized);
+      const client = CustomerProviders.Whmcs.transformWhmcsClientResponse(response);
+      await this.cacheService.setClientData(client.id, client);
 
       this.logger.log(`Fetched client details for client ${clientId}`);
-      return normalized;
+      return client;
     } catch (error) {
       this.logger.error(`Failed to fetch client details for client ${clientId}`, {
         error: getErrorMessage(error),
@@ -92,7 +92,7 @@ export class WhmcsClientService {
    * Get client details by email
    * Returns WhmcsClient (type inferred from domain mapper)
    */
-  async getClientDetailsByEmail(email: string): Promise<NormalizedWhmcsClient> {
+  async getClientDetailsByEmail(email: string): Promise<WhmcsClient> {
     try {
       const response = await this.connectionService.getClientDetailsByEmail(email);
 
@@ -104,11 +104,11 @@ export class WhmcsClientService {
         throw new NotFoundException(`Client with email ${email} not found`);
       }
 
-      const normalized = normalizeWhmcsClientResponse(response);
-      await this.cacheService.setClientData(normalized.id, normalized);
+      const client = CustomerProviders.Whmcs.transformWhmcsClientResponse(response);
+      await this.cacheService.setClientData(client.id, client);
 
       this.logger.log(`Fetched client details by email: ${email}`);
-      return normalized;
+      return client;
     } catch (error) {
       this.logger.error(`Failed to fetch client details by email: ${email}`, {
         error: getErrorMessage(error),
diff --git a/apps/bff/src/integrations/whmcs/utils/whmcs-client.utils.ts b/apps/bff/src/integrations/whmcs/utils/whmcs-client.utils.ts
index 03bc4d5a..89c9a050 100644
--- a/apps/bff/src/integrations/whmcs/utils/whmcs-client.utils.ts
+++ b/apps/bff/src/integrations/whmcs/utils/whmcs-client.utils.ts
@@ -1,32 +1,15 @@
-import {
-  addressSchema,
-  userSchema,
-  type Address,
-  type User,
-  type UserAuth,
-} from "@customer-portal/domain/customer";
-import type {
-  WhmcsClient,
-  WhmcsClientResponse,
-  WhmcsCustomField,
-  WhmcsUser,
-} from "@customer-portal/domain/customer/providers/whmcs/raw.types";
+import type { WhmcsClient } from "@customer-portal/domain/customer";
 
-type RawCustomFields = WhmcsClient["customfields"];
-type RawUsers = WhmcsClient["users"];
+type CustomFieldValueMap = Record<string, string>;
 
-const truthyStrings = new Set(["1", "true", "yes", "y", "on"]);
-const falsyStrings = new Set(["0", "false", "no", "n", "off"]);
+const isRecordOfStrings = (value: unknown): value is Record<string, string> =>
+  typeof value === "object" &&
+  value !== null &&
+  !Array.isArray(value) &&
+  Object.values(value).every(v => typeof v === "string");
 
-const toNumber = (value: unknown): number | null => {
-  if (value === undefined || value === null) return null;
-  if (typeof value === "number" && Number.isFinite(value)) return value;
-  if (typeof value === "string") {
-    const parsed = Number(value);
-    return Number.isFinite(parsed) ? parsed : null;
-  }
-  return null;
-};
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+  typeof value === "object" && value !== null && !Array.isArray(value);
 
 const toOptionalString = (value: unknown): string | undefined => {
   if (value === undefined || value === null) return undefined;
@@ -37,232 +20,72 @@ const toOptionalString = (value: unknown): string | undefined => {
   return undefined;
 };
 
-const toNullableBoolean = (value: unknown): boolean | null | undefined => {
-  if (value === undefined) return undefined;
-  if (value === null) return null;
-  if (typeof value === "boolean") return value;
-  if (typeof value === "number") return value === 0 ? false : true;
-  if (typeof value === "string") {
-    const normalized = value.trim().toLowerCase();
-    if (truthyStrings.has(normalized)) return true;
-    if (falsyStrings.has(normalized)) return false;
-  }
-  return undefined;
-};
-
-const isCustomFieldObject = (value: unknown): value is WhmcsCustomField =>
-  typeof value === "object" && value !== null && !Array.isArray(value);
-
-const isRecordOfStrings = (value: unknown): value is Record<string, string> =>
-  typeof value === "object" &&
-  value !== null &&
-  !Array.isArray(value) &&
-  Object.values(value).every(v => typeof v === "string");
-
-const normalizeCustomFields = (raw: RawCustomFields): Record<string, string> | undefined => {
+const normalizeCustomFields = (raw: WhmcsClient["customfields"]): CustomFieldValueMap | undefined => {
   if (!raw) return undefined;
 
-  if (Array.isArray(raw)) {
-    const map = raw.reduce<Record<string, string>>((acc, field) => {
-      if (!field) return acc;
-      const idKey = toOptionalString(field.id)?.trim();
-      const nameKey = toOptionalString(field.name)?.trim();
-      const value = field.value === undefined || field.value === null ? "" : String(field.value);
-
-      if (idKey) acc[idKey] = value;
-      if (nameKey) acc[nameKey] = value;
-      return acc;
-    }, {});
-
-    return Object.keys(map).length ? map : undefined;
-  }
-
   if (isRecordOfStrings(raw)) {
-    const stringRecord = raw as Record<string, string>;
-    const map = Object.entries(stringRecord).reduce<Record<string, string>>((acc, [key, value]) => {
+    const map = Object.entries(raw).reduce<CustomFieldValueMap>((acc, [key, value]) => {
       const trimmedKey = key.trim();
       if (!trimmedKey) return acc;
       acc[trimmedKey] = value;
       return acc;
     }, {});
-
     return Object.keys(map).length ? map : undefined;
   }
 
-  if (isCustomFieldObject(raw) && "customfield" in raw) {
-    const nested = raw.customfield;
-    if (!nested) return undefined;
-    if (Array.isArray(nested)) return normalizeCustomFields(nested);
-    if (isCustomFieldObject(nested)) return normalizeCustomFields([nested]);
-  }
+  const addFieldToMap = (field: unknown, acc: CustomFieldValueMap) => {
+    if (!isPlainObject(field)) return;
+    const idKey = toOptionalString(field.id)?.trim();
+    const nameKey = toOptionalString(field.name)?.trim();
+    const value =
+      field.value === undefined || field.value === null ? "" : String(field.value);
 
-  return undefined;
-};
-
-const normalizeUsers = (raw: RawUsers): NormalizedWhmcsUser[] | undefined => {
-  if (!raw) return undefined;
-
-  const rawUsers: WhmcsUser[] = Array.isArray(raw)
-    ? raw
-    : Array.isArray(raw.user)
-      ? raw.user
-      : raw.user
-        ? [raw.user]
-        : [];
-
-  if (rawUsers.length === 0) return undefined;
-
-  const normalized = rawUsers
-    .map<NormalizedWhmcsUser | null>(user => {
-      if (!user) return null;
-      const id = toNumber(user.id);
-      const name = toOptionalString(user.name);
-      const email = toOptionalString(user.email);
-      if (id === null || !name || !email) return null;
-
-      return {
-        id,
-        name,
-        email,
-        is_owner: toNullableBoolean(user.is_owner) ?? undefined,
-      };
-    })
-    .filter((user): user is NormalizedWhmcsUser => user !== null);
-
-  return normalized.length ? normalized : undefined;
-};
-
-export interface NormalizedWhmcsUser {
-  id: number;
-  name: string;
-  email: string;
-  is_owner?: boolean;
-}
-
-export interface NormalizedWhmcsClient
-  extends Omit<
-    WhmcsClient,
-    | "id"
-    | "client_id"
-    | "owner_user_id"
-    | "userid"
-    | "customfields"
-    | "users"
-    | "allowSingleSignOn"
-    | "email_verified"
-    | "marketing_emails_opt_in"
-    | "defaultpaymethodid"
-    | "currency"
-  > {
-  id: number;
-  client_id?: number | null;
-  owner_user_id?: number | null;
-  userid?: number | null;
-  customfields?: Record<string, string>;
-  users?: NormalizedWhmcsUser[];
-  allowSingleSignOn?: boolean | null;
-  email_verified?: boolean | null;
-  marketing_emails_opt_in?: boolean | null;
-  defaultpaymethodid: number | null;
-  currency: number | null;
-  address?: Address;
-  raw: WhmcsClient;
-}
-
-export const deriveAddressFromClient = (client: WhmcsClient): Address | undefined => {
-  const address = addressSchema.parse({
-    address1: client.address1 ?? null,
-    address2: client.address2 ?? null,
-    city: client.city ?? null,
-    state: client.fullstate ?? client.state ?? null,
-    postcode: client.postcode ?? null,
-    country: client.country ?? null,
-    countryCode: client.countrycode ?? null,
-    phoneNumber:
-      client.phonenumberformatted ?? client.phonenumber ?? client.telephoneNumber ?? null,
-    phoneCountryCode: client.phonecc ?? null,
-  });
-
-  const hasValues = Object.values(address).some(
-    value => value !== undefined && value !== null && value !== ""
-  );
-
-  return hasValues ? address : undefined;
-};
-
-export const normalizeWhmcsClient = (rawClient: WhmcsClient): NormalizedWhmcsClient => {
-  const id = toNumber(rawClient.id);
-  if (id === null) {
-    throw new Error("WHMCS client ID missing or invalid.");
-  }
-
-  const clientId = toNumber(rawClient.client_id);
-  const ownerUserId = toNumber(rawClient.owner_user_id);
-  const userId = toNumber(rawClient.userid);
-
-  return {
-    ...rawClient,
-    id,
-    client_id: clientId,
-    owner_user_id: ownerUserId,
-    userid: userId,
-    customfields: normalizeCustomFields(rawClient.customfields),
-    users: normalizeUsers(rawClient.users),
-    allowSingleSignOn: toNullableBoolean(rawClient.allowSingleSignOn) ?? null,
-    email_verified: toNullableBoolean(rawClient.email_verified) ?? null,
-    marketing_emails_opt_in: toNullableBoolean(rawClient.marketing_emails_opt_in) ?? null,
-    defaultpaymethodid: toNumber(rawClient.defaultpaymethodid),
-    currency: toNumber(rawClient.currency),
-    address: deriveAddressFromClient(rawClient),
-    raw: rawClient,
+    if (idKey) acc[idKey] = value;
+    if (nameKey) acc[nameKey] = value;
   };
-};
 
-export const normalizeWhmcsClientResponse = (
-  response: WhmcsClientResponse
-): NormalizedWhmcsClient => normalizeWhmcsClient(response.client);
+  if (Array.isArray(raw)) {
+    const map = raw.reduce<CustomFieldValueMap>((acc, field) => {
+      addFieldToMap(field, acc);
+      return acc;
+    }, {});
+    return Object.keys(map).length ? map : undefined;
+  }
 
-export const getCustomFieldValue = (
-  client: NormalizedWhmcsClient,
-  key: string | number
-): string | undefined => {
-  if (!client.customfields) return undefined;
-  const lookupKey = typeof key === "number" ? String(key) : key;
-  const value = client.customfields[lookupKey];
-  if (value !== undefined) return value;
-
-  if (typeof key === "string") {
-    const numeric = Number.parseInt(key, 10);
-    if (!Number.isNaN(numeric)) {
-      return client.customfields[String(numeric)];
+  if (isPlainObject(raw) && "customfield" in raw) {
+    const nested = raw.customfield;
+    if (Array.isArray(nested)) {
+      return normalizeCustomFields(nested);
+    }
+    if (nested) {
+      return normalizeCustomFields([nested]);
     }
   }
 
   return undefined;
 };
 
-export const buildUserProfile = (userAuth: UserAuth, client: NormalizedWhmcsClient): User => {
-  const payload = {
-    id: userAuth.id,
-    email: userAuth.email,
-    role: userAuth.role,
-    emailVerified: userAuth.emailVerified,
-    mfaEnabled: userAuth.mfaEnabled,
-    lastLoginAt: userAuth.lastLoginAt,
-    createdAt: userAuth.createdAt,
-    updatedAt: userAuth.updatedAt,
-    firstname: client.firstname ?? null,
-    lastname: client.lastname ?? null,
-    fullname: client.fullname ?? null,
-    companyname: client.companyname ?? null,
-    phonenumber:
-      client.phonenumberformatted ?? client.phonenumber ?? client.telephoneNumber ?? null,
-    language: client.language ?? null,
-    currency_code: client.currency_code ?? null,
-    address: client.address ?? undefined,
-  };
+/**
+ * Safely read a WHMCS custom field value by id or name without duplicating
+ * normalization logic at call sites.
+ */
+export const getCustomFieldValue = (
+  client: WhmcsClient,
+  key: string | number
+): string | undefined => {
+  const map = normalizeCustomFields(client.customfields);
+  if (!map) return undefined;
 
-  return userSchema.parse(payload);
+  const lookupKey = typeof key === "number" ? String(key) : key;
+  const direct = map[lookupKey];
+  if (direct !== undefined) return direct;
+
+  if (typeof key === "string") {
+    const numeric = Number.parseInt(key, 10);
+    if (!Number.isNaN(numeric)) {
+      return map[String(numeric)];
+    }
+  }
+
+  return undefined;
 };
-
-export const getNumericClientId = (client: NormalizedWhmcsClient): number => client.id;
diff --git a/apps/bff/src/integrations/whmcs/whmcs.service.ts b/apps/bff/src/integrations/whmcs/whmcs.service.ts
index 772baca8..c2d16a9b 100644
--- a/apps/bff/src/integrations/whmcs/whmcs.service.ts
+++ b/apps/bff/src/integrations/whmcs/whmcs.service.ts
@@ -2,7 +2,7 @@ import { Injectable, Inject } from "@nestjs/common";
 import type { Invoice, InvoiceList } from "@customer-portal/domain/billing";
 import type { Subscription, SubscriptionList } from "@customer-portal/domain/subscriptions";
 import type { PaymentMethodList, PaymentGatewayList } from "@customer-portal/domain/payments";
-import { Providers as CustomerProviders, type Address } from "@customer-portal/domain/customer";
+import { Providers as CustomerProviders, type Address, type WhmcsClient } from "@customer-portal/domain/customer";
 import { WhmcsConnectionOrchestratorService } from "./connection/services/whmcs-connection-orchestrator.service";
 import { WhmcsInvoiceService, InvoiceFilters } from "./services/whmcs-invoice.service";
 import {
@@ -18,7 +18,6 @@ import type { WhmcsGetClientsProductsParams } from "@customer-portal/domain/subs
 import type { WhmcsProductListResponse } from "@customer-portal/domain/subscriptions";
 import type { WhmcsCatalogProductListResponse } from "@customer-portal/domain/catalog";
 import { Logger } from "nestjs-pino";
-import { deriveAddressFromClient, type NormalizedWhmcsClient } from "./utils/whmcs-client.utils";
 
 @Injectable()
 export class WhmcsService {
@@ -124,7 +123,7 @@ export class WhmcsService {
    * Get client details by ID
    * Returns internal WhmcsClient (type inferred)
    */
-  async getClientDetails(clientId: number): Promise<NormalizedWhmcsClient> {
+  async getClientDetails(clientId: number): Promise<WhmcsClient> {
     return this.clientService.getClientDetails(clientId);
   }
 
@@ -132,7 +131,7 @@ export class WhmcsService {
    * Get client details by email
    * Returns internal WhmcsClient (type inferred)
    */
-  async getClientDetailsByEmail(email: string): Promise<NormalizedWhmcsClient> {
+  async getClientDetailsByEmail(email: string): Promise<WhmcsClient> {
     return this.clientService.getClientDetailsByEmail(email);
   }
 
@@ -151,7 +150,7 @@ export class WhmcsService {
    */
   async getClientAddress(clientId: number): Promise<Address> {
     const customer = await this.clientService.getClientDetails(clientId);
-    return customer.address ?? deriveAddressFromClient(customer.raw) ?? ({} as Address);
+    return (customer.address ?? {}) as Address;
   }
 
   async updateClientAddress(clientId: number, address: Partial<Address>): Promise<void> {
diff --git a/apps/bff/src/modules/auth/infra/workflows/workflows/whmcs-link-workflow.service.ts b/apps/bff/src/modules/auth/infra/workflows/workflows/whmcs-link-workflow.service.ts
index 55d7dc6f..28c33292 100644
--- a/apps/bff/src/modules/auth/infra/workflows/workflows/whmcs-link-workflow.service.ts
+++ b/apps/bff/src/modules/auth/infra/workflows/workflows/whmcs-link-workflow.service.ts
@@ -13,10 +13,7 @@ import { SalesforceService } from "@bff/integrations/salesforce/salesforce.servi
 import { getErrorMessage } from "@bff/core/utils/error.util";
 import { mapPrismaUserToDomain } from "@bff/infra/mappers";
 import type { User } from "@customer-portal/domain/customer";
-import {
-  getCustomFieldValue,
-  getNumericClientId,
-} from "@bff/integrations/whmcs/utils/whmcs-client.utils";
+import { getCustomFieldValue } from "@bff/integrations/whmcs/utils/whmcs-client.utils";
 // No direct Customer import - use inferred type from WHMCS service
 
 @Injectable()
@@ -67,7 +64,7 @@ export class WhmcsLinkWorkflowService {
         throw new UnauthorizedException("Unable to verify account. Please try again later.");
       }
 
-      const clientNumericId = getNumericClientId(clientDetails);
+      const clientNumericId = clientDetails.id;
 
       try {
         const existingMapping = await this.mappingsService.findByWhmcsClientId(clientNumericId);
diff --git a/apps/bff/src/modules/users/users.service.ts b/apps/bff/src/modules/users/users.service.ts
index 3fdb51d2..ab65fc5e 100644
--- a/apps/bff/src/modules/users/users.service.ts
+++ b/apps/bff/src/modules/users/users.service.ts
@@ -11,6 +11,7 @@ import {
 import {
   Providers as CustomerProviders,
   addressSchema,
+  combineToUser,
   type Address,
   type User,
 } from "@customer-portal/domain/customer";
@@ -21,7 +22,6 @@ import { dashboardSummarySchema } from "@customer-portal/domain/dashboard";
 import { WhmcsService } from "@bff/integrations/whmcs/whmcs.service";
 import { SalesforceService } from "@bff/integrations/salesforce/salesforce.service";
 import { MappingsService } from "@bff/modules/id-mappings/mappings.service";
-import { buildUserProfile } from "@bff/integrations/whmcs/utils/whmcs-client.utils";
 
 // Use a subset of PrismaUser for auth-related updates only
 type UserUpdateData = Partial<
@@ -132,7 +132,7 @@ export class UsersService {
       // Map Prisma user to UserAuth
       const userAuth = CustomerProviders.Portal.mapPrismaUserToUserAuth(user);
 
-      return buildUserProfile(userAuth, whmcsClient);
+      return combineToUser(userAuth, whmcsClient);
     } catch (error) {
       this.logger.error("Failed to fetch client profile from WHMCS", {
         error: getErrorMessage(error),
@@ -530,15 +530,10 @@ export class UsersService {
       let currency = "JPY"; // Default
       try {
         const client = await this.whmcsService.getClientDetails(mapping.whmcsClientId);
-        const currencyCodeFromClient =
+        const resolvedCurrency =
           typeof client.currency_code === "string" && client.currency_code.trim().length > 0
             ? client.currency_code
-            : undefined;
-        const currencyCodeFromRaw =
-          typeof client.raw.currency_code === "string" && client.raw.currency_code.trim().length > 0
-            ? client.raw.currency_code
-            : undefined;
-        const resolvedCurrency = currencyCodeFromClient ?? currencyCodeFromRaw ?? null;
+            : null;
         if (resolvedCurrency) {
           currency = resolvedCurrency;
         }
diff --git a/apps/portal/src/features/account/hooks/useProfileData.ts b/apps/portal/src/features/account/hooks/useProfileData.ts
index 5863b17e..3144de97 100644
--- a/apps/portal/src/features/account/hooks/useProfileData.ts
+++ b/apps/portal/src/features/account/hooks/useProfileData.ts
@@ -4,7 +4,6 @@ import { useEffect, useState, useCallback } from "react";
 import { useAuthStore } from "@/features/auth/services/auth.store";
 import { accountService } from "@/features/account/services/account.service";
 import { logger } from "@customer-portal/logging";
-import { getCountryCodeByName } from "@/lib/constants/countries";
 
 // Use centralized profile types
 import type { ProfileEditFormData, Address } from "@customer-portal/domain/customer";
@@ -40,21 +39,14 @@ export function useProfileData() {
       setLoading(true);
       const address = await accountService.getAddress().catch(() => null);
       if (address) {
-        const normalizeCountry = (value?: string | null) => {
-          if (!value) return "";
-          if (value.length === 2) return value.toUpperCase();
-          return getCountryCodeByName(value) ?? value;
-        };
-        const normalizedCountry = normalizeCountry(address.country);
-        const normalizedCountryCode = normalizeCountry(address.countryCode ?? address.country);
         const normalizedAddress: Address = {
           address1: address.address1 || "",
           address2: address.address2 || "",
           city: address.city || "",
           state: address.state || "",
           postcode: address.postcode || "",
-          country: normalizedCountry,
-          countryCode: normalizedCountryCode,
+          country: address.country || "",
+          countryCode: address.countryCode || "",
           phoneNumber: address.phoneNumber || "",
           phoneCountryCode: address.phoneCountryCode || "",
         };
diff --git a/apps/portal/src/features/billing/hooks/useBilling.ts b/apps/portal/src/features/billing/hooks/useBilling.ts
index ec2a0d4a..2c6eaed6 100644
--- a/apps/portal/src/features/billing/hooks/useBilling.ts
+++ b/apps/portal/src/features/billing/hooks/useBilling.ts
@@ -25,12 +25,9 @@ import {
   type InvoiceList,
   type InvoiceSsoLink,
   type InvoiceQueryParams,
-  type InvoiceStatus,
   // Schemas
   invoiceSchema,
   invoiceListSchema,
-  // Constants
-  INVOICE_STATUS,
 } from "@customer-portal/domain/billing";
 
 import { type PaymentMethodList } from "@customer-portal/domain/payments";
@@ -51,28 +48,6 @@ const EMPTY_PAYMENT_METHODS: PaymentMethodList = {
   totalCount: 0,
 };
 
-const FALLBACK_STATUS: InvoiceStatus = INVOICE_STATUS.DRAFT;
-
-function ensureInvoiceStatus(invoice: Invoice): Invoice {
-  return {
-    ...invoice,
-    status: (invoice.status as InvoiceStatus | undefined) ?? FALLBACK_STATUS,
-  };
-}
-
-function normalizeInvoiceList(list: InvoiceList): InvoiceList {
-  return {
-    ...list,
-    invoices: list.invoices.map(ensureInvoiceStatus),
-    pagination: {
-      page: list.pagination?.page ?? 1,
-      totalItems: list.pagination?.totalItems ?? 0,
-      totalPages: list.pagination?.totalPages ?? 0,
-      nextCursor: list.pagination?.nextCursor,
-    },
-  };
-}
-
 // Type helpers for React Query
 type InvoicesQueryKey = ReturnType<typeof queryKeys.billing.invoices>;
 type InvoiceQueryKey = ReturnType<typeof queryKeys.billing.invoice>;
@@ -121,8 +96,7 @@ async function fetchInvoices(params?: InvoiceQueryParams): Promise<InvoiceList>
     query ? { params: { query } } : undefined
   );
   const data = getDataOrDefault(response, EMPTY_INVOICE_LIST);
-  const parsed = invoiceListSchema.parse(data);
-  return normalizeInvoiceList(parsed);
+  return invoiceListSchema.parse(data);
 }
 
 async function fetchInvoice(id: string): Promise<Invoice> {
@@ -130,8 +104,7 @@ async function fetchInvoice(id: string): Promise<Invoice> {
     params: { path: { id } },
   });
   const invoice = getDataOrThrow(response, "Invoice not found");
-  const parsed = invoiceSchema.parse(invoice);
-  return ensureInvoiceStatus(parsed);
+  return invoiceSchema.parse(invoice);
 }
 
 async function fetchPaymentMethods(): Promise<PaymentMethodList> {
diff --git a/packages/domain/billing/providers/whmcs/mapper.ts b/packages/domain/billing/providers/whmcs/mapper.ts
index c74f8572..219248fd 100644
--- a/packages/domain/billing/providers/whmcs/mapper.ts
+++ b/packages/domain/billing/providers/whmcs/mapper.ts
@@ -14,6 +14,7 @@ import {
   type WhmcsInvoiceItemsRaw,
   whmcsInvoiceItemsRawSchema,
 } from "./raw.types";
+import { parseAmount, formatDate } from "../../providers/whmcs/utils";
 
 export interface TransformInvoiceOptions {
   defaultCurrencyCode?: string;
@@ -47,32 +48,6 @@ function mapStatus(status: string): Invoice["status"] {
   return mapped;
 }
 
-function parseAmount(amount: string | number | undefined): number {
-  if (typeof amount === "number") {
-    return amount;
-  }
-  if (!amount) {
-    return 0;
-  }
-
-  const cleaned = String(amount).replace(/[^\d.-]/g, "");
-  const parsed = Number.parseFloat(cleaned);
-  return Number.isNaN(parsed) ? 0 : parsed;
-}
-
-function formatDate(input?: string): string | undefined {
-  if (!input) {
-    return undefined;
-  }
-
-  const date = new Date(input);
-  if (Number.isNaN(date.getTime())) {
-    return undefined;
-  }
-
-  return date.toISOString();
-}
-
 function mapItems(rawItems: unknown): InvoiceItem[] {
   if (!rawItems) return [];
 
diff --git a/packages/domain/customer/index.ts b/packages/domain/customer/index.ts
index 08a0e071..481b748e 100644
--- a/packages/domain/customer/index.ts
+++ b/packages/domain/customer/index.ts
@@ -31,6 +31,7 @@ export type {
   ProfileDisplayData,  // Profile display data (alias)
   UserProfile,    // Alias for User
   AuthenticatedUser, // Alias for authenticated user
+  WhmcsClient,    // Provider-normalized WHMCS client shape
 } from "./schema";
 
 // ============================================================================
diff --git a/packages/domain/providers/whmcs/utils.ts b/packages/domain/providers/whmcs/utils.ts
new file mode 100644
index 00000000..302d5d07
--- /dev/null
+++ b/packages/domain/providers/whmcs/utils.ts
@@ -0,0 +1,61 @@
+/**
+ * Shared WHMCS Provider Utilities
+ * Single source of truth for WHMCS data parsing
+ * 
+ * Raw API types are source of truth - no fallbacks or variations expected.
+ */
+
+/**
+ * Parse amount from WHMCS API response
+ * WHMCS returns amounts as strings or numbers
+ */
+export function parseAmount(amount: string | number | undefined): number {
+  if (typeof amount === "number") return amount;
+  if (!amount) return 0;
+  
+  const cleaned = String(amount).replace(/[^\d.-]/g, "");
+  const parsed = Number.parseFloat(cleaned);
+  return Number.isNaN(parsed) ? 0 : parsed;
+}
+
+/**
+ * Format date from WHMCS API to ISO string
+ * Returns undefined if input is invalid
+ */
+export function formatDate(input?: string | null): string | undefined {
+  if (!input) return undefined;
+  
+  const date = new Date(input);
+  if (Number.isNaN(date.getTime())) return undefined;
+  
+  return date.toISOString();
+}
+
+/**
+ * Normalize status using provided status map
+ * Generic helper for consistent status mapping
+ */
+export function normalizeStatus<T extends string>(
+  status: string | undefined,
+  statusMap: Record<string, T>,
+  defaultStatus: T
+): T {
+  if (!status) return defaultStatus;
+  const mapped = statusMap[status.trim().toLowerCase()];
+  return mapped ?? defaultStatus;
+}
+
+/**
+ * Normalize billing cycle using provided cycle map
+ * Generic helper for consistent cycle mapping
+ */
+export function normalizeCycle<T extends string>(
+  cycle: string | undefined,
+  cycleMap: Record<string, T>,
+  defaultCycle: T
+): T {
+  if (!cycle) return defaultCycle;
+  const normalized = cycle.trim().toLowerCase().replace(/[_\s-]+/g, " ");
+  return cycleMap[normalized] ?? defaultCycle;
+}
+