diff --git a/apps/portal/src/components/common/FormField/FormField.tsx b/apps/portal/src/components/common/FormField/FormField.tsx
index c3d926ff..62ce1835 100644
--- a/apps/portal/src/components/common/FormField/FormField.tsx
+++ b/apps/portal/src/components/common/FormField/FormField.tsx
@@ -13,14 +13,27 @@ interface FormFieldProps
   error?: string;
   helperText?: string;
   required?: boolean;
-  labelProps?: Omit<LabelProps, "htmlFor" | "required">;
+  labelProps?: Omit<LabelProps, "htmlFor">;
   fieldId?: string;
   children?: React.ReactNode;
+  containerClassName?: string;
+  inputClassName?: string;
 }
 
 const FormField = forwardRef<HTMLInputElement, FormFieldProps>(
   (
-    { label, error, helperText, required, labelProps, fieldId, className, children, ...inputProps },
+    {
+      label,
+      error,
+      helperText,
+      required,
+      labelProps,
+      fieldId,
+      containerClassName,
+      inputClassName,
+      children,
+      ...inputProps
+    },
     ref
   ) => {
     const generatedId = useId();
@@ -29,40 +42,47 @@ const FormField = forwardRef<HTMLInputElement, FormFieldProps>(
     const helperTextId = helperText ? `${id}-helper` : undefined;
 
     return (
-      <div className={cn("space-y-1", className)}>
+      <div className={cn("space-y-1", containerClassName)}>
         {label && (
           <Label
             htmlFor={id}
-            required={required}
-            variant={error ? "error" : "default"}
-            {...labelProps}
+            className={cn(
+              "block text-sm font-medium text-gray-700",
+              error && "text-red-600",
+              labelProps?.className
+            )}
+            {...(labelProps ? { ...labelProps, className: undefined } : undefined)}
           >
-            {label}
+            <span>{label}</span>
+            {required ? (
+              <span aria-hidden="true" className="ml-1 text-red-600">
+                *
+              </span>
+            ) : null}
           </Label>
         )}
         {children ? (
-          isValidElement(children) ? (
-            cloneElement(
-              children as React.ReactElement<any>,
-              {
+          isValidElement(children)
+            ? cloneElement(children, {
                 id,
                 "aria-invalid": error ? "true" : undefined,
                 "aria-describedby": cn(errorId, helperTextId) || undefined,
-              } as any
-            )
-          ) : (
-            children
-          )
+              } as Record<string, unknown>)
+            : children
         ) : (
           <Input
             id={id}
             ref={ref}
-            error={error}
             aria-invalid={error ? "true" : undefined}
             aria-describedby={cn(errorId, helperTextId) || undefined}
+            className={cn(
+              error &&
+                "border-red-500 focus-visible:ring-red-500 focus-visible:ring-offset-2",
+              inputClassName,
+              inputProps.className
+            )}
             {...(() => {
-              const { children: _children, dangerouslySetInnerHTML: _dangerouslySetInnerHTML, ...rest } =
-                inputProps as Record<string, unknown>;
+              const { className, ...rest } = inputProps;
               return rest;
             })()}
           />
diff --git a/apps/portal/src/components/guards/profile-completion-guard.tsx b/apps/portal/src/components/guards/profile-completion-guard.tsx
deleted file mode 100644
index 292a6069..00000000
--- a/apps/portal/src/components/guards/profile-completion-guard.tsx
+++ /dev/null
@@ -1,78 +0,0 @@
-"use client";
-
-import { useEffect } from "react";
-import { useProfileCompletion } from "@/features/account/hooks";
-import { MapPinIcon, ExclamationTriangleIcon } from "@heroicons/react/24/outline";
-
-interface ProfileCompletionGuardProps {
-  children: React.ReactNode;
-  requireComplete?: boolean;
-  showBanner?: boolean;
-}
-
-export function ProfileCompletionGuard({
-  children,
-  requireComplete = false,
-  showBanner = true,
-}: ProfileCompletionGuardProps) {
-  const { isComplete, loading, redirectToCompletion } = useProfileCompletion();
-
-  useEffect(() => {
-    // If profile completion is required and profile is incomplete, redirect
-    if (!loading && requireComplete && !isComplete) {
-      redirectToCompletion();
-    }
-  }, [loading, requireComplete, isComplete, redirectToCompletion]);
-
-  // Show loading state
-  if (loading) {
-    return (
-      <div className="flex items-center justify-center p-8">
-        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-600"></div>
-        <span className="ml-3 text-gray-600">Loading...</span>
-      </div>
-    );
-  }
-
-  // If requiring complete profile and it's not complete, show loading (will redirect)
-  if (requireComplete && !isComplete) {
-    return (
-      <div className="flex items-center justify-center p-8">
-        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-600"></div>
-        <span className="ml-3 text-gray-600">Redirecting to complete profile...</span>
-      </div>
-    );
-  }
-
-  // Show banner if profile is incomplete and banner is enabled
-  if (!isComplete && showBanner) {
-    return (
-      <div>
-        <div className="bg-gradient-to-r from-amber-50 to-orange-50 border border-amber-200 rounded-xl p-6 mb-6">
-          <div className="flex items-start space-x-4">
-            <div className="flex-shrink-0">
-              <ExclamationTriangleIcon className="h-6 w-6 text-amber-600" />
-            </div>
-            <div className="flex-1">
-              <h3 className="text-lg font-semibold text-amber-900 mb-2">Complete Your Profile</h3>
-              <p className="text-amber-800 mb-4">
-                Some features may be limited until you complete your profile information.
-              </p>
-              <button
-                onClick={redirectToCompletion}
-                className="inline-flex items-center px-4 py-2 bg-amber-600 text-white rounded-lg hover:bg-amber-700 transition-colors font-medium"
-              >
-                <MapPinIcon className="h-4 w-4 mr-2" />
-                Complete Profile
-              </button>
-            </div>
-          </div>
-        </div>
-        {children}
-      </div>
-    );
-  }
-
-  // Profile is complete or banner is disabled, show children
-  return <>{children}</>;
-}
diff --git a/apps/portal/src/components/layout/AppShell/AppShell.tsx b/apps/portal/src/components/layout/AppShell/AppShell.tsx
index eede195b..3637d75c 100644
--- a/apps/portal/src/components/layout/AppShell/AppShell.tsx
+++ b/apps/portal/src/components/layout/AppShell/AppShell.tsx
@@ -21,7 +21,8 @@ export function AppShell({ children }: AppShellProps) {
   const { hydrated, hasCheckedAuth, loading } = useAuthStore();
   const pathname = usePathname();
   const router = useRouter();
-  const { data: activeSubscriptions } = useActiveSubscriptions();
+  const activeSubscriptionsQuery = useActiveSubscriptions();
+  const activeSubscriptions = activeSubscriptionsQuery.data ?? [];
 
   // Initialize with a stable default to avoid hydration mismatch
   const [expandedItems, setExpandedItems] = useState<string[]>([]);
@@ -71,6 +72,9 @@ export function AppShell({ children }: AppShellProps) {
     void (async () => {
       try {
         const prof = await accountService.getProfile();
+        if (!prof) {
+          return;
+        }
         useAuthStore.setState(state => ({
           ...state,
           user: state.user
@@ -80,7 +84,7 @@ export function AppShell({ children }: AppShellProps) {
                 lastName: prof.lastName || state.user.lastName,
                 phone: prof.phone || state.user.phone,
               }
-            : (prof as unknown as typeof state.user),
+            : prof,
         }));
       } catch {
         // best-effort profile hydration; ignore errors
diff --git a/apps/portal/src/components/layout/dashboard-layout.tsx b/apps/portal/src/components/layout/dashboard-layout.tsx
index dd4f3994..d2ff3704 100644
--- a/apps/portal/src/components/layout/dashboard-layout.tsx
+++ b/apps/portal/src/components/layout/dashboard-layout.tsx
@@ -86,7 +86,8 @@ export function DashboardLayout({ children }: DashboardLayoutProps) {
   const { user, isAuthenticated, checkAuth } = useAuthStore();
   const pathname = usePathname();
   const router = useRouter();
-  const { data: activeSubscriptions } = useActiveSubscriptions();
+  const activeSubscriptionsQuery = useActiveSubscriptions();
+  const activeSubscriptions = activeSubscriptionsQuery.data ?? [];
 
   // Initialize expanded items from localStorage or defaults
   const [expandedItems, setExpandedItems] = useState<string[]>(() => {
diff --git a/apps/portal/src/components/ui/button.tsx b/apps/portal/src/components/ui/button.tsx
index 3fd41cfb..d9b3a966 100644
--- a/apps/portal/src/components/ui/button.tsx
+++ b/apps/portal/src/components/ui/button.tsx
@@ -1,7 +1,8 @@
-import type { AnchorHTMLAttributes, ButtonHTMLAttributes } from "react";
+import type { AnchorHTMLAttributes, ButtonHTMLAttributes, ReactNode } from "react";
 import { forwardRef } from "react";
 import { cva, type VariantProps } from "class-variance-authority";
 import { cn } from "@/shared/utils";
+import { LoadingSpinner } from "@/components/ui/loading-spinner";
 
 const buttonVariants = cva(
   "inline-flex items-center justify-center rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:opacity-50 disabled:pointer-events-none ring-offset-background",
@@ -28,39 +29,76 @@ const buttonVariants = cva(
   }
 );
 
+interface ButtonExtras {
+  leftIcon?: ReactNode;
+  rightIcon?: ReactNode;
+  loading?: boolean;
+  isLoading?: boolean;
+  loadingText?: ReactNode;
+}
+
 type ButtonAsAnchorProps = {
   as: "a";
   href: string;
 } & AnchorHTMLAttributes<HTMLAnchorElement> &
-  VariantProps<typeof buttonVariants>;
+  VariantProps<typeof buttonVariants> &
+  ButtonExtras;
 
 type ButtonAsButtonProps = {
   as?: "button";
 } & ButtonHTMLAttributes<HTMLButtonElement> &
-  VariantProps<typeof buttonVariants>;
+  VariantProps<typeof buttonVariants> &
+  ButtonExtras;
 
 export type ButtonProps = ButtonAsAnchorProps | ButtonAsButtonProps;
 
 const Button = forwardRef<HTMLButtonElement | HTMLAnchorElement, ButtonProps>((props, ref) => {
+  const {
+    leftIcon,
+    rightIcon,
+    loading: loadingProp,
+    isLoading,
+    loadingText,
+    children,
+    ...rest
+  } = props;
+
+  const loading = loadingProp ?? isLoading ?? false;
+
   if (props.as === "a") {
-    const { className, variant, size, as: _as, href, ...anchorProps } = props;
+    const { className, variant, size, as: _as, href, ...anchorProps } = rest as ButtonAsAnchorProps;
     return (
       <a
         className={cn(buttonVariants({ variant, size, className }))}
         href={href}
         ref={ref as React.Ref<HTMLAnchorElement>}
+        aria-busy={loading || undefined}
         {...anchorProps}
-      />
+      >
+        <span className="inline-flex items-center gap-2">
+          {loading ? <LoadingSpinner size="sm" /> : leftIcon}
+          <span>{loading ? loadingText ?? children : children}</span>
+          {!loading && rightIcon ? <span className="ml-1">{rightIcon}</span> : null}
+        </span>
+      </a>
     );
   }
 
-  const { className, variant, size, as: _as, ...buttonProps } = props;
+  const { className, variant, size, as: _as, disabled, ...buttonProps } = rest as ButtonAsButtonProps;
   return (
     <button
       className={cn(buttonVariants({ variant, size, className }))}
       ref={ref as React.Ref<HTMLButtonElement>}
+      disabled={loading || disabled}
+      aria-busy={loading || undefined}
       {...buttonProps}
-    />
+    >
+      <span className="inline-flex items-center gap-2">
+        {loading ? <LoadingSpinner size="sm" /> : leftIcon}
+        <span>{loading ? loadingText ?? children : children}</span>
+        {!loading && rightIcon ? <span className="ml-1">{rightIcon}</span> : null}
+      </span>
+    </button>
   );
 });
 Button.displayName = "Button";
diff --git a/apps/portal/src/components/ui/index.ts b/apps/portal/src/components/ui/index.ts
index 56f0b519..399c2c9f 100644
--- a/apps/portal/src/components/ui/index.ts
+++ b/apps/portal/src/components/ui/index.ts
@@ -7,17 +7,17 @@
 export { Button, buttonVariants } from "./button";
 export type { ButtonProps } from "./button";
 
-export { Input, inputVariants } from "./input";
+export { Input } from "./input";
 export type { InputProps } from "./input";
 
-export { Label, labelVariants } from "./label";
+export { Label } from "./label";
 export type { LabelProps } from "./label";
 
 export { ErrorMessage, errorMessageVariants } from "./error-message";
 export type { ErrorMessageProps } from "./error-message";
 
 // Status and Feedback Components
-export { StatusPill, statusPillVariants } from "./status-pill";
+export { StatusPill } from "./status-pill";
 export type { StatusPillProps } from "./status-pill";
 
 export { Badge, badgeVariants } from "./badge";
diff --git a/apps/portal/src/components/ui/input.tsx b/apps/portal/src/components/ui/input.tsx
index 75ff1b44..3a2ac525 100644
--- a/apps/portal/src/components/ui/input.tsx
+++ b/apps/portal/src/components/ui/input.tsx
@@ -1,22 +1,31 @@
-import type { InputHTMLAttributes } from "react";
+import type { InputHTMLAttributes, ReactNode } from "react";
 import { forwardRef } from "react";
 import { cn } from "@/shared/utils";
 
-export type InputProps = InputHTMLAttributes<HTMLInputElement>;
+export interface InputProps extends InputHTMLAttributes<HTMLInputElement> {
+  error?: ReactNode;
+}
 
-const Input = forwardRef<HTMLInputElement, InputProps>(({ className, type, ...props }, ref) => {
-  return (
-    <input
-      type={type}
-      className={cn(
-        "flex h-10 w-full rounded-md border border-gray-300 bg-white px-3 py-2 text-sm ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-gray-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-500 focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
-        className
-      )}
-      ref={ref}
-      {...props}
-    />
-  );
-});
+const Input = forwardRef<HTMLInputElement, InputProps>(
+  ({ className, type, error, ...props }, ref) => {
+    const isInvalid = Boolean(error);
+
+    return (
+      <input
+        type={type}
+        className={cn(
+          "flex h-10 w-full rounded-md border border-gray-300 bg-white px-3 py-2 text-sm ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-gray-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-500 focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
+          isInvalid &&
+            "border-red-500 focus-visible:ring-red-500 focus-visible:ring-offset-2",
+          className
+        )}
+        aria-invalid={isInvalid || undefined}
+        ref={ref}
+        {...props}
+      />
+    );
+  }
+);
 Input.displayName = "Input";
 
 export { Input };
diff --git a/apps/portal/src/components/ui/status-pill.tsx b/apps/portal/src/components/ui/status-pill.tsx
index eadbb8c3..d931fbdb 100644
--- a/apps/portal/src/components/ui/status-pill.tsx
+++ b/apps/portal/src/components/ui/status-pill.tsx
@@ -1,18 +1,15 @@
-import type { HTMLAttributes } from "react";
+import { forwardRef, type HTMLAttributes, type ReactNode } from "react";
+import { cn } from "@/shared/utils";
 
-type Variant = "success" | "warning" | "info" | "neutral" | "error";
-
-interface StatusPillProps extends HTMLAttributes<HTMLSpanElement> {
+export type StatusPillProps = HTMLAttributes<HTMLSpanElement> & {
   label: string;
-  variant?: Variant;
-}
+  variant?: "success" | "warning" | "info" | "neutral" | "error";
+  size?: "sm" | "md" | "lg";
+  icon?: ReactNode;
+};
 
-export function StatusPill({
-  label,
-  variant = "neutral",
-  className = "",
-  ...rest
-}: StatusPillProps) {
+export const StatusPill = forwardRef<HTMLSpanElement, StatusPillProps>(
+  ({ label, variant = "neutral", size = "md", icon, className, ...rest }, ref) => {
   const tone =
     variant === "success"
       ? "bg-green-50 text-green-700 ring-green-600/20"
@@ -24,12 +21,29 @@ export function StatusPill({
             ? "bg-red-50 text-red-700 ring-red-600/20"
             : "bg-gray-50 text-gray-700 ring-gray-400/30";
 
-  return (
-    <span
-      className={`inline-flex items-center rounded-[var(--cp-pill-radius)] px-[var(--cp-pill-px)] py-[var(--cp-pill-py)] text-xs font-medium ring-1 ring-inset ${tone} ${className}`}
-      {...rest}
-    >
-      {label}
-    </span>
-  );
-}
+  const sizing =
+    size === "sm"
+      ? "px-2 py-0.5 text-xs"
+      : size === "lg"
+        ? "px-4 py-1.5 text-sm"
+        : "px-3 py-1 text-xs";
+
+    return (
+      <span
+        ref={ref}
+        className={cn(
+          "inline-flex items-center rounded-full ring-1 ring-inset gap-1",
+          sizing,
+          tone,
+          className
+        )}
+        {...rest}
+      >
+        {icon ? <span className="flex items-center justify-center">{icon}</span> : null}
+        <span>{label}</span>
+      </span>
+    );
+  }
+);
+
+StatusPill.displayName = "StatusPill";
diff --git a/apps/portal/src/components/ui/sub-card.tsx b/apps/portal/src/components/ui/sub-card.tsx
index 71b62fd0..0675d8a7 100644
--- a/apps/portal/src/components/ui/sub-card.tsx
+++ b/apps/portal/src/components/ui/sub-card.tsx
@@ -1,30 +1,34 @@
-import type { ReactNode } from "react";
+import { forwardRef, type ReactNode } from "react";
 
-interface SubCardProps {
+export interface SubCardProps {
   title?: string;
   icon?: ReactNode;
   right?: ReactNode;
-  header?: ReactNode; // Optional custom header content (overrides title/icon/right layout)
-  footer?: ReactNode; // Optional footer section separated by a subtle divider
+  header?: ReactNode;
+  footer?: ReactNode;
   children: ReactNode;
   className?: string;
   headerClassName?: string;
   bodyClassName?: string;
 }
 
-export function SubCard({
-  title,
-  icon,
-  right,
-  header,
-  footer,
-  children,
-  className = "",
-  headerClassName = "",
-  bodyClassName = "",
-}: SubCardProps) {
-  return (
+export const SubCard = forwardRef<HTMLDivElement, SubCardProps>(
+  (
+    {
+      title,
+      icon,
+      right,
+      header,
+      footer,
+      children,
+      className = "",
+      headerClassName = "",
+      bodyClassName = "",
+    },
+    ref
+  ) => (
     <div
+      ref={ref}
       className={`border-[var(--cp-card-border)] bg-white shadow-[var(--cp-card-shadow)] rounded-[var(--cp-card-radius)] p-[var(--cp-card-padding)] transition-shadow duration-[var(--cp-transition-normal)] hover:shadow-[var(--cp-card-shadow-lg)] ${className}`}
     >
       {header ? (
@@ -47,5 +51,6 @@ export function SubCard({
         </div>
       ) : null}
     </div>
-  );
-}
+  )
+);
+SubCard.displayName = "SubCard";
diff --git a/apps/portal/src/core/api/client.ts b/apps/portal/src/core/api/client.ts
index 0ebc92b0..2c249099 100644
--- a/apps/portal/src/core/api/client.ts
+++ b/apps/portal/src/core/api/client.ts
@@ -1,4 +1,4 @@
-
+/**
  * Core API client configuration
  * Wraps the shared generated client to inject portal-specific behavior like auth headers.
  */
@@ -7,16 +7,16 @@ import {
   createClient as createOpenApiClient,
   type ApiClient as GeneratedApiClient,
   type AuthHeaderResolver,
+  resolveBaseUrl,
 } from "@customer-portal/api-client";
 import { env } from "../config/env";
 
-const baseUrl = env.NEXT_PUBLIC_API_BASE;
-
 let authHeaderResolver: AuthHeaderResolver | undefined;
 
 const resolveAuthHeader: AuthHeaderResolver = () => authHeaderResolver?.();
 
-export const apiClient: GeneratedApiClient = createOpenApiClient(baseUrl, {
+export const apiClient: GeneratedApiClient = createOpenApiClient({
+  baseUrl: resolveBaseUrl(env.NEXT_PUBLIC_API_BASE),
   getAuthHeader: resolveAuthHeader,
 });
 
@@ -24,4 +24,4 @@ export const configureApiClientAuth = (resolver?: AuthHeaderResolver) => {
   authHeaderResolver = resolver;
 };
 
-export type ApiClient = GeneratedApiClient;
\ No newline at end of file
+export type ApiClient = GeneratedApiClient;
diff --git a/apps/portal/src/core/api/index.ts b/apps/portal/src/core/api/index.ts
index 6289dcd7..f977cc93 100644
--- a/apps/portal/src/core/api/index.ts
+++ b/apps/portal/src/core/api/index.ts
@@ -3,3 +3,4 @@ export { queryKeys } from "./query-keys";
 
 export type { ApiClient } from "./client";
 export type { AuthHeaderResolver } from "@customer-portal/api-client";
+export type { InvoiceQueryParams } from "./types";
diff --git a/apps/portal/src/core/api/query-keys.ts b/apps/portal/src/core/api/query-keys.ts
index 738be29d..8ac097bd 100644
--- a/apps/portal/src/core/api/query-keys.ts
+++ b/apps/portal/src/core/api/query-keys.ts
@@ -3,56 +3,75 @@
  * Centralized query key factory for consistent caching
  */
 
+import type { InvoiceQueryParams } from "./types";
+
+const createScope = <const TScope extends readonly string[]>(scope: TScope) => ({
+  all: scope,
+  extend: <const TParts extends readonly unknown[]>(...parts: TParts) =>
+    [...scope, ...parts] as const,
+});
+
+const authScope = createScope(["auth"] as const);
+const dashboardScope = createScope(["dashboard"] as const);
+const billingScope = createScope(["billing"] as const);
+const subscriptionsScope = createScope(["subscriptions"] as const);
+const catalogScope = createScope(["catalog"] as const);
+
+const auth = {
+  all: authScope.all,
+  profile: () => authScope.extend("profile"),
+};
+
+const dashboard = {
+  all: dashboardScope.all,
+  summary: () => dashboardScope.extend("summary"),
+  stats: () => dashboardScope.extend("stats"),
+  activity: (filters?: readonly string[]) => dashboardScope.extend("activity", filters ?? []),
+  nextInvoice: () => dashboardScope.extend("next-invoice"),
+};
+
+const billing = {
+  all: billingScope.all,
+  invoices: (params?: InvoiceQueryParams) => billingScope.extend("invoices", params ?? {}),
+  invoice: (id: string) => billingScope.extend("invoice", id),
+  paymentMethods: () => billingScope.extend("payment-methods"),
+  gateways: () => billingScope.extend("gateways"),
+};
+
+const subscriptions = {
+  all: subscriptionsScope.all,
+  list: (params?: { status?: string }) => subscriptionsScope.extend("list", params ?? {}),
+  active: () => subscriptionsScope.extend("active"),
+  detail: (id: string | number) => subscriptionsScope.extend("detail", String(id)),
+  invoices: (subscriptionId: number, params?: { page?: number; limit?: number }) =>
+    subscriptionsScope.extend("invoices", subscriptionId, params ?? {}),
+  stats: () => subscriptionsScope.extend("stats"),
+};
+
+const catalog = {
+  all: catalogScope.all,
+  products: (type: string, params?: Record<string, unknown>) =>
+    catalogScope.extend("products", type, params ?? {}),
+  internet: {
+    all: catalogScope.extend("internet"),
+    combined: () => catalogScope.extend("internet", "combined"),
+  },
+  sim: {
+    all: catalogScope.extend("sim"),
+    combined: () => catalogScope.extend("sim", "combined"),
+  },
+  vpn: {
+    all: catalogScope.extend("vpn"),
+    combined: () => catalogScope.extend("vpn", "combined"),
+  },
+};
+
 export const queryKeys = {
-  // Auth queries
-  auth: {
-    all: ['auth'] as const,
-    profile: () => [...queryKeys.auth.all, 'profile'] as const,
-  },
-
-  // Dashboard queries  
-  dashboard: {
-    all: ['dashboard'] as const,
-    summary: () => [...queryKeys.dashboard.all, 'summary'] as const,
-  },
-
-  // Billing queries
-  billing: {
-    all: ['billing'] as const,
-    invoices: (params?: Record<string, unknown>) =>
-      [...queryKeys.billing.all, 'invoices', params ?? {}] as const,
-    invoice: (id: string) => [...queryKeys.billing.all, 'invoice', id] as const,
-    paymentMethods: () => [...queryKeys.billing.all, 'paymentMethods'] as const,
-    gateways: () => [...queryKeys.billing.all, 'gateways'] as const,
-  },
-
-  // Subscription queries
-  subscriptions: {
-    all: ['subscriptions'] as const,
-    list: (params?: Record<string, unknown>) =>
-      [...queryKeys.subscriptions.all, 'list', params ?? {}] as const,
-    detail: (id: string) => [...queryKeys.subscriptions.all, 'detail', id] as const,
-    invoices: (subscriptionId: number, params?: Record<string, unknown>) =>
-      [...queryKeys.subscriptions.all, 'invoices', subscriptionId, params ?? {}] as const,
-    stats: () => [...queryKeys.subscriptions.all, 'stats'] as const,
-  },
-
-  // Catalog queries
-  catalog: {
-    all: ['catalog'] as const,
-    products: (type: string, params?: Record<string, unknown>) =>
-      [...queryKeys.catalog.all, 'products', type, params ?? {}] as const,
-    internet: {
-      all: [...queryKeys.catalog.all, 'internet'] as const,
-      combined: () => [...queryKeys.catalog.internet.all, 'combined'] as const,
-    },
-    sim: {
-      all: [...queryKeys.catalog.all, 'sim'] as const,
-      combined: () => [...queryKeys.catalog.sim.all, 'combined'] as const,
-    },
-    vpn: {
-      all: [...queryKeys.catalog.all, 'vpn'] as const,
-      combined: () => [...queryKeys.catalog.vpn.all, 'combined'] as const,
-    },
-  },
+  auth,
+  dashboard,
+  billing,
+  subscriptions,
+  catalog,
 } as const;
+
+export type QueryKeys = typeof queryKeys;
diff --git a/apps/portal/src/core/api/response-helpers.ts b/apps/portal/src/core/api/response-helpers.ts
new file mode 100644
index 00000000..7ffef935
--- /dev/null
+++ b/apps/portal/src/core/api/response-helpers.ts
@@ -0,0 +1,24 @@
+const coerceData = <T>(container: { data?: unknown }): T | null | undefined =>
+  container.data as T | null | undefined;
+
+export const getDataOrThrow = <T>(
+  container: { data?: unknown },
+  message = "API response did not include data"
+): T => {
+  const data = coerceData<T>(container);
+  if (data === null || typeof data === "undefined") {
+    throw new Error(message);
+  }
+
+  return data;
+};
+
+export const getDataOrDefault = <T>(container: { data?: unknown }, fallback: T): T => {
+  const data = coerceData<T>(container);
+  return typeof data === "undefined" || data === null ? fallback : data;
+};
+
+export const getNullableData = <T>(container: { data?: unknown }): T | null => {
+  const data = coerceData<T>(container);
+  return typeof data === "undefined" ? null : data;
+};
diff --git a/apps/portal/src/core/api/types.ts b/apps/portal/src/core/api/types.ts
new file mode 100644
index 00000000..fc45de92
--- /dev/null
+++ b/apps/portal/src/core/api/types.ts
@@ -0,0 +1,8 @@
+export interface InvoiceQueryParams {
+  page?: number;
+  limit?: number;
+  status?: string;
+  search?: string;
+  sort?: string;
+  [key: string]: unknown;
+}
diff --git a/apps/portal/src/core/config/env.ts b/apps/portal/src/core/config/env.ts
index 5fc4855a..38aa6e30 100644
--- a/apps/portal/src/core/config/env.ts
+++ b/apps/portal/src/core/config/env.ts
@@ -1,7 +1,7 @@
 import { z } from "zod";
 
 const EnvSchema = z.object({
-  NEXT_PUBLIC_API_BASE: z.string().url().default("http://localhost:4000/api"),
+  NEXT_PUBLIC_API_BASE: z.string().url().default("http://localhost:4000"),
   NEXT_PUBLIC_APP_NAME: z.string().default("Assist Solutions Portal"),
   NEXT_PUBLIC_APP_VERSION: z.string().default("0.1.0"),
 });
diff --git a/apps/portal/src/core/validation/index.ts b/apps/portal/src/core/validation/index.ts
new file mode 100644
index 00000000..1262893d
--- /dev/null
+++ b/apps/portal/src/core/validation/index.ts
@@ -0,0 +1,67 @@
+import { useMemo } from "react";
+
+export type ValidationRule = (value: string) => string | null;
+
+const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+export const validationRules = {
+  required: (message = "This field is required"): ValidationRule => value =>
+    value && value.toString().trim().length > 0 ? null : message,
+  email: (message = "Enter a valid email address"): ValidationRule => value =>
+    !value || emailRegex.test(value.toString()) ? null : message,
+  minLength: (length: number, message?: string): ValidationRule => value =>
+    value && value.toString().length >= length
+      ? null
+      : message ?? `Must be at least ${length} characters`,
+  pattern: (pattern: RegExp, message = "Invalid value"): ValidationRule => value =>
+    !value || pattern.test(value.toString()) ? null : message,
+};
+
+export interface FieldValidationResult {
+  isValid: boolean;
+  errors: string[];
+}
+
+export const validateField = (
+  value: string,
+  rules: ValidationRule[]
+): FieldValidationResult => {
+  const errors = rules
+    .map(rule => rule(value))
+    .filter((error): error is string => Boolean(error));
+
+  return {
+    isValid: errors.length === 0,
+    errors,
+  };
+};
+
+export const validateForm = (
+  values: Record<string, string>,
+  config: Record<string, ValidationRule[]>
+) => {
+  const fieldErrors: Record<string, string | undefined> = {};
+  let isValid = true;
+
+  for (const [field, fieldRules] of Object.entries(config)) {
+    const { isValid: fieldValid, errors } = validateField(values[field] ?? "", fieldRules);
+    if (!fieldValid) {
+      fieldErrors[field] = errors[0];
+      isValid = false;
+    }
+  }
+
+  return { isValid, errors: fieldErrors };
+};
+
+export const useFormValidation = () =>
+  useMemo(
+    () => ({
+      validationRules,
+      validateField,
+      validateForm,
+    }),
+    []
+  );
+
+export type ValidationRules = typeof validationRules;
diff --git a/apps/portal/src/features/account/hooks/index.ts b/apps/portal/src/features/account/hooks/index.ts
index 1d7f23b5..c770b90b 100644
--- a/apps/portal/src/features/account/hooks/index.ts
+++ b/apps/portal/src/features/account/hooks/index.ts
@@ -1,4 +1,3 @@
-export { useProfileCompletion } from "./useProfileCompletion";
 export { useProfileData } from "./useProfileData";
 export { useProfileEdit } from "./useProfileEdit";
 export { useAddressEdit } from "./useAddressEdit";
diff --git a/apps/portal/src/features/account/hooks/useProfileCompletion.ts b/apps/portal/src/features/account/hooks/useProfileCompletion.ts
deleted file mode 100644
index e456a0f5..00000000
--- a/apps/portal/src/features/account/hooks/useProfileCompletion.ts
+++ /dev/null
@@ -1,62 +0,0 @@
-"use client";
-
-import { useState, useEffect } from "react";
-import { useRouter } from "next/navigation";
-import { apiClient } from "@/core/api";
-
-interface Address {
-  street: string | null;
-  streetLine2: string | null;
-  city: string | null;
-  state: string | null;
-  postalCode: string | null;
-  country: string | null;
-}
-
-interface BillingInfo {
-  company: string | null;
-  email: string;
-  phone: string | null;
-  address: Address;
-  isComplete: boolean;
-}
-
-interface ProfileCompletionStatus {
-  isComplete: boolean;
-  loading: boolean;
-  redirectToCompletion: () => void;
-}
-
-export function useProfileCompletion(): ProfileCompletionStatus {
-  const [isComplete, setIsComplete] = useState<boolean>(true); // Default to true to avoid flash
-  const [loading, setLoading] = useState(true);
-  const router = useRouter();
-
-  useEffect(() => {
-    const checkProfileCompletion = async () => {
-      try {
-        const response = await apiClient.GET("/me/billing");
-        const billingInfo = response.data;
-        setIsComplete(billingInfo.isComplete);
-      } catch (error) {
-        console.error("Failed to check profile completion:", error);
-        // On error, assume incomplete to be safe
-        setIsComplete(false);
-      } finally {
-        setLoading(false);
-      }
-    };
-
-    void checkProfileCompletion();
-  }, []);
-
-  const redirectToCompletion = () => {
-    router.push("/account/profile?complete=true");
-  };
-
-  return {
-    isComplete,
-    loading,
-    redirectToCompletion,
-  };
-}
diff --git a/apps/portal/src/features/account/services/account.service.ts b/apps/portal/src/features/account/services/account.service.ts
index c5ddbce4..9fb279b4 100644
--- a/apps/portal/src/features/account/services/account.service.ts
+++ b/apps/portal/src/features/account/services/account.service.ts
@@ -1,13 +1,7 @@
 import { apiClient } from "@/core/api";
+import { getDataOrThrow, getNullableData } from "@/core/api/response-helpers";
 import type { Address, AuthUser } from "@customer-portal/domain";
 
-const ensureData = <T>(data: T | undefined): T => {
-  if (typeof data === "undefined") {
-    throw new Error("No data returned from server");
-  }
-  return data;
-};
-
 type ProfileUpdateInput = {
   firstName?: string;
   lastName?: string;
@@ -16,22 +10,22 @@ type ProfileUpdateInput = {
 
 export const accountService = {
   async getProfile() {
-    const response = await apiClient.GET('/me');
-    return ensureData<AuthUser | null>(response.data);
+    const response = await apiClient.GET('/api/me');
+    return getNullableData<AuthUser>(response);
   },
 
   async updateProfile(update: ProfileUpdateInput) {
-    const response = await apiClient.PATCH('/me', { body: update });
-    return ensureData<AuthUser>(response.data);
+    const response = await apiClient.PATCH('/api/me', { body: update });
+    return getDataOrThrow<AuthUser>(response, "Failed to update profile");
   },
 
   async getAddress() {
-    const response = await apiClient.GET('/me/address');
-    return ensureData<Address | null>(response.data);
+    const response = await apiClient.GET('/api/me/address');
+    return getNullableData<Address>(response);
   },
 
   async updateAddress(address: Address) {
-    const response = await apiClient.PATCH('/me/address', { body: address });
-    return ensureData<Address>(response.data);
+    const response = await apiClient.PATCH('/api/me/address', { body: address });
+    return getDataOrThrow<Address>(response, "Failed to update address");
   },
 };
diff --git a/apps/portal/src/features/auth/components/LinkWhmcsForm/LinkWhmcsForm.tsx b/apps/portal/src/features/auth/components/LinkWhmcsForm/LinkWhmcsForm.tsx
index 9bca4275..37f1d673 100644
--- a/apps/portal/src/features/auth/components/LinkWhmcsForm/LinkWhmcsForm.tsx
+++ b/apps/portal/src/features/auth/components/LinkWhmcsForm/LinkWhmcsForm.tsx
@@ -103,10 +103,7 @@ export function LinkWhmcsForm({ onTransferred, className = "" }: LinkWhmcsFormPr
       }
 
       try {
-        const result = await linkWhmcs({
-          email: formData.email.trim(),
-          password: formData.password,
-        });
+        const result = await linkWhmcs(formData.email.trim(), formData.password);
 
         onTransferred?.({ needsPasswordSet: result.needsPasswordSet, email: formData.email.trim() });
       } catch (err) {
diff --git a/apps/portal/src/features/auth/components/PasswordResetForm/PasswordResetForm.tsx b/apps/portal/src/features/auth/components/PasswordResetForm/PasswordResetForm.tsx
index 0246caa5..cdf3afe3 100644
--- a/apps/portal/src/features/auth/components/PasswordResetForm/PasswordResetForm.tsx
+++ b/apps/portal/src/features/auth/components/PasswordResetForm/PasswordResetForm.tsx
@@ -10,7 +10,7 @@ import Link from "next/link";
 import { Button, Input, ErrorMessage } from "@/components/ui";
 import { FormField } from "@/components/common/FormField";
 import { usePasswordReset } from "../../hooks/use-auth";
-import { useFormValidation, commonValidationSchemas, z } from "@customer-portal/domain";
+import { useFormValidation } from "@/core/validation";
 // removed unused type imports
 
 interface PasswordResetFormProps {
@@ -47,6 +47,7 @@ export function PasswordResetForm({
   className = "",
 }: PasswordResetFormProps) {
   const { requestPasswordReset, resetPassword, loading, error, clearError } = usePasswordReset();
+  const { validationRules, validateField } = useFormValidation();
 
   const [requestData, setRequestData] = useState<RequestFormData>({
     email: "",
diff --git a/apps/portal/src/features/auth/components/SessionTimeoutWarning.tsx b/apps/portal/src/features/auth/components/SessionTimeoutWarning.tsx
index e8a25074..d12cf323 100644
--- a/apps/portal/src/features/auth/components/SessionTimeoutWarning.tsx
+++ b/apps/portal/src/features/auth/components/SessionTimeoutWarning.tsx
@@ -27,7 +27,7 @@ export function SessionTimeoutWarning({
 
     const expiryTime = Date.parse(tokens.expiresAt);
     if (Number.isNaN(expiryTime)) {
-      logger.warn("Invalid expiresAt on auth tokens", { expiresAt: tokens.expiresAt });
+      logger.warn({ expiresAt: tokens.expiresAt }, "Invalid expiresAt on auth tokens");
       expiryRef.current = null;
       setShowWarning(false);
       setTimeLeft(0);
@@ -133,4 +133,3 @@ export function SessionTimeoutWarning({
   );
 }
 
-
diff --git a/apps/portal/src/features/auth/components/SetPasswordForm/SetPasswordForm.tsx b/apps/portal/src/features/auth/components/SetPasswordForm/SetPasswordForm.tsx
index d09780a8..1965982e 100644
--- a/apps/portal/src/features/auth/components/SetPasswordForm/SetPasswordForm.tsx
+++ b/apps/portal/src/features/auth/components/SetPasswordForm/SetPasswordForm.tsx
@@ -10,7 +10,7 @@ import Link from "next/link";
 import { Button, Input, ErrorMessage } from "@/components/ui";
 import { FormField } from "@/components/common/FormField";
 import { useWhmcsLink } from "../../hooks/use-auth";
-import { useFormValidation, commonValidationSchemas, z } from "@customer-portal/domain";
+import { useFormValidation } from "@/core/validation";
 
 interface SetPasswordFormProps {
   email?: string;
@@ -41,6 +41,7 @@ export function SetPasswordForm({
   className = "",
 }: SetPasswordFormProps) {
   const { setPassword, loading, error, clearError } = useWhmcsLink();
+  const { validationRules, validateField } = useFormValidation();
 
   const [formData, setFormData] = useState<FormData>({
     email: initialEmail,
diff --git a/apps/portal/src/features/auth/index.ts b/apps/portal/src/features/auth/index.ts
index 2720e9a5..5c7e097a 100644
--- a/apps/portal/src/features/auth/index.ts
+++ b/apps/portal/src/features/auth/index.ts
@@ -4,16 +4,3 @@
  */
 
 export { useAuthStore } from "./services/auth.store";
-export type {
-  SignupData,
-  LoginData,
-  LinkWhmcsData,
-  SetPasswordData,
-  RequestPasswordResetData,
-  ResetPasswordData,
-  ChangePasswordData,
-  CheckPasswordNeededData,
-  CheckPasswordNeededResponse,
-  AuthResponse,
-  LinkResponse,
-} from "./api";
diff --git a/apps/portal/src/features/auth/services/auth.store.ts b/apps/portal/src/features/auth/services/auth.store.ts
index 5f9c47d6..94c13dfa 100644
--- a/apps/portal/src/features/auth/services/auth.store.ts
+++ b/apps/portal/src/features/auth/services/auth.store.ts
@@ -6,6 +6,7 @@
 import { create } from "zustand";
 import { persist, createJSONStorage } from "zustand/middleware";
 import { apiClient, configureApiClientAuth } from "@/core/api";
+import { getDataOrDefault, getDataOrThrow } from "@/core/api/response-helpers";
 import type {
   AuthTokens,
   SignupRequest,
@@ -36,6 +37,21 @@ type RawAuthTokens =
   | (Omit<AuthTokens, "expiresAt"> & { expiresAt: string | number | Date })
   | LegacyAuthTokens;
 
+interface AuthPayload {
+  user: AuthUser;
+  tokens: RawAuthTokens;
+}
+
+interface PasswordCheckPayload {
+  needsPasswordSet: boolean;
+  userExists: boolean;
+  email?: string;
+}
+
+interface LinkWhmcsPayload {
+  needsPasswordSet: boolean;
+}
+
 const toIsoString = (value: string | number | Date | null | undefined) => {
 
   if (value instanceof Date) {
@@ -169,18 +185,17 @@ export const useAuthStore = create<AuthStoreState>()(
       login: async (credentials: LoginRequest) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/login', { body: credentials });
-          if (response.data) {
-            const tokens = normalizeAuthTokens(response.data.tokens as RawAuthTokens);
-            set({
-              user: response.data.user,
-              tokens,
-              isAuthenticated: true,
-              loading: false,
-              error: null,
-              persistSession: Boolean(credentials.rememberMe),
-            });
-          }
+          const response = await apiClient.POST('/api/auth/login', { body: credentials });
+          const payload = getDataOrThrow<AuthPayload>(response, 'Failed to login');
+          const tokens = normalizeAuthTokens(payload.tokens);
+          set({
+            user: payload.user,
+            tokens,
+            isAuthenticated: true,
+            loading: false,
+            error: null,
+            persistSession: Boolean(credentials.rememberMe),
+          });
         } catch (error) {
           const authError = error as AuthError;
           set({
@@ -198,17 +213,16 @@ export const useAuthStore = create<AuthStoreState>()(
       signup: async (data: SignupRequest) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/signup', { body: data });
-          if (response.data) {
-            const tokens = normalizeAuthTokens(response.data.tokens as RawAuthTokens);
-            set({
-              user: response.data.user,
-              tokens,
-              isAuthenticated: true,
-              loading: false,
-              error: null,
-            });
-          }
+          const response = await apiClient.POST('/api/auth/signup', { body: data });
+          const payload = getDataOrThrow<AuthPayload>(response, 'Failed to sign up');
+          const tokens = normalizeAuthTokens(payload.tokens);
+          set({
+            user: payload.user,
+            tokens,
+            isAuthenticated: true,
+            loading: false,
+            error: null,
+          });
         } catch (error) {
           const authError = error as AuthError;
           set({
@@ -228,7 +242,7 @@ export const useAuthStore = create<AuthStoreState>()(
         // Call logout API if we have tokens
         if (tokens?.accessToken) {
           try {
-            await apiClient.POST('/auth/logout');
+            await apiClient.POST('/api/auth/logout');
           } catch (error) {
             console.warn("Logout API call failed:", error);
             // Continue with local logout even if API call fails
@@ -247,7 +261,7 @@ export const useAuthStore = create<AuthStoreState>()(
       requestPasswordReset: async (data: ForgotPasswordRequest) => {
         set({ loading: true, error: null });
         try {
-          await apiClient.POST('/auth/request-password-reset', { body: data });
+          await apiClient.POST('/api/auth/request-password-reset', { body: data });
           set({ loading: false });
         } catch (error) {
           const authError = error as AuthError;
@@ -259,11 +273,14 @@ export const useAuthStore = create<AuthStoreState>()(
       resetPassword: async (data: ResetPasswordRequest) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/reset-password', { body: data });
-          const { user, tokens } = response.data!;
-          const normalizedTokens = normalizeAuthTokens(tokens as RawAuthTokens);
+          const response = await apiClient.POST('/api/auth/reset-password', { body: data });
+          const payload = getDataOrThrow<AuthPayload>(
+            response,
+            'Failed to reset password'
+          );
+          const normalizedTokens = normalizeAuthTokens(payload.tokens);
           set({
-            user,
+            user: payload.user,
             tokens: normalizedTokens,
             isAuthenticated: true,
             loading: false,
@@ -290,11 +307,14 @@ export const useAuthStore = create<AuthStoreState>()(
 
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/change-password', { body: data });
-          const { user, tokens: newTokens } = response.data!;
-          const normalizedTokens = normalizeAuthTokens(newTokens as RawAuthTokens);
+          const response = await apiClient.POST('/api/auth/change-password', { body: data });
+          const payload = getDataOrThrow<AuthPayload>(
+            response,
+            'Failed to change password'
+          );
+          const normalizedTokens = normalizeAuthTokens(payload.tokens);
           set({
-            user,
+            user: payload.user,
             tokens: normalizedTokens,
             loading: false,
             error: null,
@@ -309,8 +329,11 @@ export const useAuthStore = create<AuthStoreState>()(
       checkPasswordNeeded: async (email: string) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/check-password-needed', { body: { email } });
-          const result = response.data!;
+          const response = await apiClient.POST('/api/auth/check-password-needed', { body: { email } });
+          const result = getDataOrThrow<PasswordCheckPayload>(
+            response,
+            'Failed to check password requirements'
+          );
           set({ loading: false });
           return result;
         } catch (error) {
@@ -323,8 +346,11 @@ export const useAuthStore = create<AuthStoreState>()(
       linkWhmcs: async (email: string, password: string) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/link-whmcs', { body: { email, password } });
-          const result = response.data!;
+          const response = await apiClient.POST('/api/auth/link-whmcs', { body: { email, password } });
+          const result = getDataOrThrow<LinkWhmcsPayload>(
+            response,
+            'Failed to link WHMCS account'
+          );
           set({ loading: false });
           return result;
         } catch (error) {
@@ -337,11 +363,11 @@ export const useAuthStore = create<AuthStoreState>()(
       setPassword: async (email: string, password: string) => {
         set({ loading: true, error: null });
         try {
-          const response = await apiClient.POST('/auth/set-password', { body: { email, password } });
-          const { user, tokens } = response.data!;
-          const normalizedTokens = normalizeAuthTokens(tokens as RawAuthTokens);
+          const response = await apiClient.POST('/api/auth/set-password', { body: { email, password } });
+          const payload = getDataOrThrow<AuthPayload>(response, 'Failed to set password');
+          const normalizedTokens = normalizeAuthTokens(payload.tokens);
           set({
-            user,
+            user: payload.user,
             tokens: normalizedTokens,
             isAuthenticated: true,
             loading: false,
@@ -377,8 +403,8 @@ export const useAuthStore = create<AuthStoreState>()(
 
         set({ loading: true });
         try {
-          const response = await apiClient.GET('/me');
-          const user = response.data ?? null;
+          const response = await apiClient.GET('/api/me');
+          const user = getDataOrDefault<AuthUser | null>(response, null);
           if (user) {
             set({ user, isAuthenticated: true, loading: false, error: null, hasCheckedAuth: true });
           } else {
diff --git a/apps/portal/src/features/billing/components/BillingSummary/BillingSummary.tsx b/apps/portal/src/features/billing/components/BillingSummary/BillingSummary.tsx
index 99371631..31d9cf5d 100644
--- a/apps/portal/src/features/billing/components/BillingSummary/BillingSummary.tsx
+++ b/apps/portal/src/features/billing/components/BillingSummary/BillingSummary.tsx
@@ -44,13 +44,11 @@ const BillingSummary = forwardRef<HTMLDivElement, BillingSummaryProps>(
       );
     }
 
-    const formatAmount = (amount: number) => {
-      return formatCurrency(amount, {
+    const formatAmount = (amount: number) =>
+      formatCurrency(amount, {
         currency: summary.currency,
-        currencySymbol: summary.currencySymbol,
         locale: getCurrencyLocale(summary.currency),
       });
-    };
 
     const summaryItems = [
       {
diff --git a/apps/portal/src/features/billing/components/InvoiceTable/InvoiceTable.tsx b/apps/portal/src/features/billing/components/InvoiceTable/InvoiceTable.tsx
index c0164786..3c89c972 100644
--- a/apps/portal/src/features/billing/components/InvoiceTable/InvoiceTable.tsx
+++ b/apps/portal/src/features/billing/components/InvoiceTable/InvoiceTable.tsx
@@ -89,7 +89,6 @@ export function InvoiceTable({
           <span className="text-sm font-medium text-gray-900">
             {formatCurrency(invoice.total, {
               currency: invoice.currency,
-              currencySymbol: invoice.currencySymbol,
               locale: getCurrencyLocale(invoice.currency),
             })}
           </span>
diff --git a/apps/portal/src/features/billing/components/PaymentMethodCard.tsx b/apps/portal/src/features/billing/components/PaymentMethodCard.tsx
new file mode 100644
index 00000000..65df310c
--- /dev/null
+++ b/apps/portal/src/features/billing/components/PaymentMethodCard.tsx
@@ -0,0 +1,79 @@
+"use client";
+
+import { CreditCardIcon, BanknotesIcon, DevicePhoneMobileIcon } from "@heroicons/react/24/outline";
+import type { PaymentMethod } from "@customer-portal/domain";
+import { StatusPill } from "@/components/ui/status-pill";
+import { cn } from "@/shared/utils";
+import type { ReactNode } from "react";
+
+interface PaymentMethodCardProps {
+  paymentMethod: PaymentMethod;
+  className?: string;
+  showActions?: boolean;
+  actionSlot?: ReactNode;
+}
+
+const getMethodIcon = (type: PaymentMethod["type"], brand?: string) => {
+  if (type === "BankAccount" || type === "RemoteBankAccount") {
+    return <BanknotesIcon className="h-6 w-6 text-gray-400" />;
+  }
+  if (brand?.toLowerCase().includes("mobile")) {
+    return <DevicePhoneMobileIcon className="h-6 w-6 text-gray-400" />;
+  }
+  return <CreditCardIcon className="h-6 w-6 text-gray-400" />;
+};
+
+const formatDescription = (method: PaymentMethod) => {
+  if (method.cardBrand && method.lastFour) {
+    return `${method.cardBrand.toUpperCase()} •••• ${method.lastFour}`;
+  }
+  if (method.type === "BankAccount" && method.lastFour) {
+    return `Bank Account •••• ${method.lastFour}`;
+  }
+  return method.description;
+};
+
+const formatExpiry = (expiryDate?: string) => {
+  if (!expiryDate) return null;
+  return `Expires ${expiryDate}`;
+};
+
+export function PaymentMethodCard({
+  paymentMethod,
+  className,
+  showActions = false,
+  actionSlot,
+}: PaymentMethodCardProps) {
+  const description = formatDescription(paymentMethod);
+  const expiry = formatExpiry(paymentMethod.expiryDate);
+  const icon = getMethodIcon(paymentMethod.type, paymentMethod.cardBrand ?? paymentMethod.ccType);
+
+  return (
+    <div
+      className={cn(
+        "flex items-center justify-between p-4 border border-gray-200 rounded-lg bg-white",
+        className
+      )}
+    >
+      <div className="flex items-center gap-4">
+        <div className="flex-shrink-0">{icon}</div>
+        <div className="space-y-1">
+          <div className="flex items-center gap-2">
+            <p className="font-medium text-gray-900">{description}</p>
+            {paymentMethod.isDefault ? (
+              <StatusPill label="Default" variant="info" size="sm" />
+            ) : null}
+          </div>
+          <div className="text-sm text-gray-500">
+            {paymentMethod.gatewayDisplayName || paymentMethod.gatewayName || paymentMethod.type}
+          </div>
+          {expiry ? <div className="text-xs text-gray-400">{expiry}</div> : null}
+        </div>
+      </div>
+
+      {showActions && actionSlot ? <div className="flex-shrink-0">{actionSlot}</div> : null}
+    </div>
+  );
+}
+
+export type { PaymentMethodCardProps };
diff --git a/apps/portal/src/features/billing/components/index.ts b/apps/portal/src/features/billing/components/index.ts
index 6002e64e..6c171e15 100644
--- a/apps/portal/src/features/billing/components/index.ts
+++ b/apps/portal/src/features/billing/components/index.ts
@@ -1,2 +1,3 @@
 export * from "./InvoiceStatusBadge";
 export * from "./InvoiceItemRow";
+export * from "./PaymentMethodCard";
diff --git a/apps/portal/src/features/billing/hooks/useBilling.ts b/apps/portal/src/features/billing/hooks/useBilling.ts
index bbc14840..28519f1e 100644
--- a/apps/portal/src/features/billing/hooks/useBilling.ts
+++ b/apps/portal/src/features/billing/hooks/useBilling.ts
@@ -9,13 +9,12 @@ import {
   type UseQueryResult,
 } from "@tanstack/react-query";
 import { apiClient, queryKeys } from "@/core/api";
+import { getDataOrDefault, getDataOrThrow } from "@/core/api/response-helpers";
+import type { InvoiceQueryParams } from "@/core/api/types";
 import type {
   Invoice,
   InvoiceList,
-  InvoiceQueryParams,
   InvoiceSsoLink,
-  InvoicePaymentLink,
-  PaymentGatewayList,
   PaymentMethodList,
 } from "@customer-portal/domain";
 
@@ -52,15 +51,6 @@ type PaymentMethodsQueryOptions = Omit<
   "queryKey" | "queryFn"
 >;
 
-type PaymentLinkMutationOptions = UseMutationOptions<
-  InvoicePaymentLink,
-  Error,
-  {
-    invoiceId: number;
-    paymentMethodId?: number;
-    gatewayName?: string;
-  }
->;
 
 type SsoLinkMutationOptions = UseMutationOptions<
   InvoiceSsoLink,
@@ -69,26 +59,18 @@ type SsoLinkMutationOptions = UseMutationOptions<
 >;
 
 async function fetchInvoices(params?: InvoiceQueryParams): Promise<InvoiceList> {
-  const response = await apiClient.GET("/invoices", params ? { params: { query: params } } : undefined);
-  return response.data ?? emptyInvoiceList;
+  const response = await apiClient.GET("/api/invoices", params ? { params: { query: params } } : undefined);
+  return getDataOrDefault(response, emptyInvoiceList);
 }
 
 async function fetchInvoice(id: string): Promise<Invoice> {
-  const response = await apiClient.GET("/invoices/{id}", { params: { path: { id } } });
-  if (!response.data) {
-    throw new Error("Invoice not found");
-  }
-  return response.data;
+  const response = await apiClient.GET("/api/invoices/{id}", { params: { path: { id } } });
+  return getDataOrThrow(response, "Invoice not found");
 }
 
 async function fetchPaymentMethods(): Promise<PaymentMethodList> {
-  const response = await apiClient.GET("/invoices/payment-methods");
-  return response.data ?? emptyPaymentMethods;
-}
-
-async function fetchPaymentGateways(): Promise<PaymentGatewayList> {
-  const response = await apiClient.GET("/invoices/payment-gateways");
-  return response.data ?? { gateways: [], totalCount: 0 };
+  const response = await apiClient.GET("/api/invoices/payment-methods");
+  return getDataOrDefault(response, emptyPaymentMethods);
 }
 
 export function useInvoices(
@@ -124,54 +106,6 @@ export function usePaymentMethods(
   });
 }
 
-export function usePaymentGateways(
-  options?: Omit<
-    UseQueryOptions<
-      PaymentGatewayList,
-      Error,
-      PaymentGatewayList,
-      ReturnType<typeof queryKeys.billing.gateways>
-    >,
-    "queryKey" | "queryFn"
-  >
-): UseQueryResult<PaymentGatewayList, Error> {
-  return useQuery({
-    queryKey: queryKeys.billing.gateways(),
-    queryFn: fetchPaymentGateways,
-    ...options,
-  });
-}
-
-export function useCreateInvoicePaymentLink(
-  options?: PaymentLinkMutationOptions
-): UseMutationResult<
-  InvoicePaymentLink,
-  Error,
-  {
-    invoiceId: number;
-    paymentMethodId?: number;
-    gatewayName?: string;
-  }
-> {
-  return useMutation({
-    mutationFn: async ({ invoiceId, paymentMethodId, gatewayName }) => {
-      const response = await apiClient.POST("/invoices/{id}/payment-link", {
-        params: {
-          path: { id: invoiceId },
-          query: {
-            paymentMethodId,
-            gatewayName,
-          },
-        },
-      });
-      if (!response.data) {
-        throw new Error("Failed to create payment link");
-      }
-      return response.data;
-    },
-    ...options,
-  });
-}
 
 export function useCreateInvoiceSsoLink(
   options?: SsoLinkMutationOptions
@@ -182,16 +116,13 @@ export function useCreateInvoiceSsoLink(
 > {
   return useMutation({
     mutationFn: async ({ invoiceId, target }) => {
-      const response = await apiClient.POST("/invoices/{id}/sso-link", {
+      const response = await apiClient.POST("/api/invoices/{id}/sso-link", {
         params: {
           path: { id: invoiceId },
           query: target ? { target } : undefined,
         },
       });
-      if (!response.data) {
-        throw new Error("Failed to create SSO link");
-      }
-      return response.data;
+      return getDataOrThrow(response, "Failed to create SSO link");
     },
     ...options,
   });
diff --git a/apps/portal/src/features/billing/hooks/usePaymentRefresh.ts b/apps/portal/src/features/billing/hooks/usePaymentRefresh.ts
index 1e80c656..c966d936 100644
--- a/apps/portal/src/features/billing/hooks/usePaymentRefresh.ts
+++ b/apps/portal/src/features/billing/hooks/usePaymentRefresh.ts
@@ -29,7 +29,7 @@ export function usePaymentRefresh<T>({
     setToast({ visible: true, text: "Refreshing payment methods...", tone: "info" });
     try {
       try {
-        await apiClient.POST("/invoices/payment-methods/refresh");
+        await apiClient.POST("/api/invoices/payment-methods/refresh");
       } catch (err) {
         // Soft-fail cache refresh, still attempt refetch
         console.warn("Payment methods cache refresh failed:", err);
diff --git a/apps/portal/src/features/billing/views/InvoiceDetail.tsx b/apps/portal/src/features/billing/views/InvoiceDetail.tsx
index c291d8f3..2c45fe64 100644
--- a/apps/portal/src/features/billing/views/InvoiceDetail.tsx
+++ b/apps/portal/src/features/billing/views/InvoiceDetail.tsx
@@ -11,6 +11,7 @@ import { PageLayout } from "@/components/layout/PageLayout";
 import { CreditCardIcon } from "@heroicons/react/24/outline";
 import { logger } from "@customer-portal/logging";
 import { apiClient } from "@/core/api";
+import { getDataOrThrow } from "@/core/api/response-helpers";
 import { openSsoLink } from "@/features/billing/utils/sso";
 import { useInvoice, useCreateInvoiceSsoLink } from "@/features/billing/hooks";
 import {
@@ -27,9 +28,11 @@ export function InvoiceDetailContainer() {
   const [loadingPayment, setLoadingPayment] = useState(false);
   const [loadingPaymentMethods, setLoadingPaymentMethods] = useState(false);
 
-  const invoiceId = parseInt(params.id as string);
+  const rawInvoiceParam = params.id;
+  const invoiceIdParam = Array.isArray(rawInvoiceParam) ? rawInvoiceParam[0] : rawInvoiceParam;
+  const invoiceId = Number.parseInt(invoiceIdParam ?? "", 10);
   const createSsoLinkMutation = useCreateInvoiceSsoLink();
-  const { data: invoice, isLoading, error } = useInvoice(invoiceId);
+  const { data: invoice, isLoading, error } = useInvoice(invoiceIdParam ?? "");
 
   const handleCreateSsoLink = (target: "view" | "download" | "pay" = "view") => {
     void (async () => {
@@ -53,10 +56,13 @@ export function InvoiceDetailContainer() {
     void (async () => {
       setLoadingPaymentMethods(true);
       try {
-        const response = await apiClient.POST('/auth/sso-link', {
-          body: { path: "index.php?rp=/account/paymentmethods" }
+        const response = await apiClient.POST('/api/auth/sso-link', {
+          body: { path: "index.php?rp=/account/paymentmethods" },
         });
-        const sso = response.data!;
+        const sso = getDataOrThrow<{ url: string }>(
+          response,
+          'Failed to create payment methods SSO link'
+        );
         openSsoLink(sso.url, { newTab: true });
       } catch (err) {
         logger.error(err, "Failed to create payment methods SSO link");
@@ -180,5 +186,3 @@ export function InvoiceDetailContainer() {
 }
 
 export default InvoiceDetailContainer;
-
-
diff --git a/apps/portal/src/features/billing/views/PaymentMethods.tsx b/apps/portal/src/features/billing/views/PaymentMethods.tsx
index 8d14908b..824d4375 100644
--- a/apps/portal/src/features/billing/views/PaymentMethods.tsx
+++ b/apps/portal/src/features/billing/views/PaymentMethods.tsx
@@ -6,8 +6,9 @@ import { ErrorBoundary } from "@/components/common";
 import { SubCard } from "@/components/ui/sub-card";
 import { useSession } from "@/features/auth/hooks";
 import { useAuthStore } from "@/features/auth/services/auth.store";
-// ApiClientError import removed - using generic error handling
+
 import { apiClient } from "@/core/api";
+import { getDataOrThrow } from "@/core/api/response-helpers";
 import { openSsoLink } from "@/features/billing/utils/sso";
 import { usePaymentRefresh } from "@/features/billing/hooks/usePaymentRefresh";
 import { PaymentMethodCard, usePaymentMethods } from "@/features/billing";
@@ -46,25 +47,32 @@ export function PaymentMethodsContainer() {
   });
 
   const openPaymentMethods = async () => {
-    try {
-      setIsLoading(true);
-      setError(null);
-      if (!isAuthenticated) {
-        setError("Please log in to access payment methods.");
-        setIsLoading(false);
-        return;
-      }
-      const response = await apiClient.POST('/auth/sso-link', {
-        body: { path: "index.php?rp=/account/paymentmethods" }
-      });
-      const sso = response.data!;
-      openSsoLink(sso.url, { newTab: true });
+    setIsLoading(true);
+    setError(null);
+
+    if (!isAuthenticated) {
+      setError("Please log in to access payment methods.");
       setIsLoading(false);
-    } catch (error) {
-      logger.error(error, "Failed to open payment methods");
-      if (error && typeof error === 'object' && 'status' in error && (error as any).status === 401)
+      return;
+    }
+
+    try {
+      const response = await apiClient.POST('/api/auth/sso-link', {
+        body: { path: "index.php?rp=/account/paymentmethods" },
+      });
+      const sso = getDataOrThrow<{ url: string }>(
+        response,
+        'Failed to open payment methods portal'
+      );
+      openSsoLink(sso.url, { newTab: true });
+    } catch (err) {
+      logger.error(err, "Failed to open payment methods");
+      if (err && typeof err === 'object' && 'status' in err && (err as any).status === 401) {
         setError("Authentication failed. Please log in again.");
-      else setError("Unable to access payment methods. Please try again later.");
+      } else {
+        setError("Unable to access payment methods. Please try again later.");
+      }
+    } finally {
       setIsLoading(false);
     }
   };
@@ -73,16 +81,22 @@ export function PaymentMethodsContainer() {
     // Placeholder hook for future logic when returning from WHMCS
   }, [isAuthenticated]);
 
-  if (error || paymentMethodsError) {
-    const errorObj =
-      error || (paymentMethodsError instanceof Error ? paymentMethodsError : new Error("Unexpected error"));
+  const combinedError = error
+    ? new Error(error)
+    : paymentMethodsError instanceof Error
+      ? paymentMethodsError
+      : paymentMethodsError
+        ? new Error(String(paymentMethodsError))
+        : null;
+
+  if (combinedError) {
     return (
       <PageLayout
         icon={<CreditCardIcon />}
         title="Payment Methods"
         description="Manage your saved payment methods and billing information"
       >
-        <AsyncBlock error={errorObj} variant="page">
+        <AsyncBlock error={combinedError} variant="page">
           <></>
         </AsyncBlock>
       </PageLayout>
@@ -97,9 +111,9 @@ export function PaymentMethodsContainer() {
     >
       <ErrorBoundary>
         <InlineToast
-        visible={paymentRefresh.toast.visible}
-        text={paymentRefresh.toast.text}
-        tone={paymentRefresh.toast.tone}
+          visible={paymentRefresh.toast.visible}
+          text={paymentRefresh.toast.text}
+          tone={paymentRefresh.toast.tone}
         />
       {/* Simplified: remove verbose banner; controls exist via buttons */}
       <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
@@ -147,7 +161,6 @@ export function PaymentMethodsContainer() {
                     key={paymentMethod.id}
                     paymentMethod={paymentMethod}
                     className="focus:outline-none focus:ring-2 focus:ring-blue-500"
-                    showActions={false}
                   />
                 ))}
               </div>
@@ -207,4 +220,3 @@ export function PaymentMethodsContainer() {
 }
 
 export default PaymentMethodsContainer;
-
diff --git a/apps/portal/src/features/catalog/components/base/AddressConfirmation.tsx b/apps/portal/src/features/catalog/components/base/AddressConfirmation.tsx
index daabcd46..1769a38d 100644
--- a/apps/portal/src/features/catalog/components/base/AddressConfirmation.tsx
+++ b/apps/portal/src/features/catalog/components/base/AddressConfirmation.tsx
@@ -24,7 +24,7 @@ interface BillingInfo {
   company: string | null;
   email: string;
   phone: string | null;
-  address: Address;
+  address: Address | null;
   isComplete: boolean;
 }
 
@@ -54,32 +54,33 @@ export function AddressConfirmation({
   const fetchBillingInfo = useCallback(async () => {
     try {
       setLoading(true);
-      const data = (await accountService.getAddress()) || null;
+      const data = await accountService.getAddress();
+      const isComplete = !!(
+        data &&
+        data.street &&
+        data.city &&
+        data.state &&
+        data.postalCode &&
+        data.country
+      );
+
       setBillingInfo({
         company: null,
         email: "",
         phone: null,
         address: data,
-        isComplete: !!(
-          data &&
-          data.street &&
-          data.city &&
-          data.state &&
-          data.postalCode &&
-          data.country
-        ),
+        isComplete,
       });
 
-      // Since address is required at signup, it should always be complete
-      // But we still need verification for Internet orders
       if (requiresAddressVerification) {
-        // For Internet orders, don't auto-confirm - require explicit verification
         setAddressConfirmed(false);
-        onAddressIncomplete(); // Keep disabled until explicitly confirmed
-      } else {
-        // For other order types, auto-confirm since address exists from signup
-        if (data) onAddressConfirmed(data);
+        onAddressIncomplete();
+      } else if (isComplete && data) {
+        onAddressConfirmed(data);
         setAddressConfirmed(true);
+      } else {
+        onAddressIncomplete();
+        setAddressConfirmed(false);
       }
     } catch (err) {
       setError(err instanceof Error ? err.message : "Failed to load address");
@@ -99,7 +100,7 @@ export function AddressConfirmation({
 
     setEditing(true);
     setEditedAddress(
-      billingInfo?.address || {
+      billingInfo?.address ?? {
         street: "",
         streetLine2: "",
         city: "",
@@ -134,17 +135,17 @@ export function AddressConfirmation({
       try {
         setError(null);
 
-        // Build minimal PATCH payload with only provided fields
-        const payload: Record<string, string> = {};
-        if (editedAddress.street) payload.street = editedAddress.street;
-        if (editedAddress.streetLine2) payload.streetLine2 = editedAddress.streetLine2;
-        if (editedAddress.city) payload.city = editedAddress.city;
-        if (editedAddress.state) payload.state = editedAddress.state;
-        if (editedAddress.postalCode) payload.postalCode = editedAddress.postalCode;
-        if (editedAddress.country) payload.country = editedAddress.country;
+        const sanitizedAddress: Address = {
+          street: editedAddress.street?.trim() || null,
+          streetLine2: editedAddress.streetLine2?.trim() || null,
+          city: editedAddress.city?.trim() || null,
+          state: editedAddress.state?.trim() || null,
+          postalCode: editedAddress.postalCode?.trim() || null,
+          country: editedAddress.country?.trim() || null,
+        };
 
         // Persist to server (WHMCS via BFF)
-        const updatedAddress = await accountService.updateAddress(payload);
+        const updatedAddress = await accountService.updateAddress(sanitizedAddress);
 
         // Rebuild BillingInfo from updated address
         const updatedInfo: BillingInfo = {
@@ -234,6 +235,8 @@ export function AddressConfirmation({
 
   if (!billingInfo) return null;
 
+  const address = billingInfo.address;
+
   return wrap(
     <>
       <div className="flex items-center justify-between mb-4">
@@ -379,18 +382,18 @@ export function AddressConfirmation({
         </div>
       ) : (
         <div>
-          {billingInfo.address.street ? (
+          {address?.street ? (
             <div className="space-y-4">
               <div className="text-gray-900 space-y-1">
-                <p className="font-semibold text-base">{billingInfo.address.street}</p>
-                {billingInfo.address.streetLine2 && (
-                  <p className="text-gray-700">{billingInfo.address.streetLine2}</p>
-                )}
+                <p className="font-semibold text-base">{address.street}</p>
+                {address.streetLine2 ? (
+                  <p className="text-gray-700">{address.streetLine2}</p>
+                ) : null}
                 <p className="text-gray-700">
-                  {billingInfo.address.city}, {billingInfo.address.state}{" "}
-                  {billingInfo.address.postalCode}
+                  {[address.city, address.state].filter(Boolean).join(", ")}
+                  {address.postalCode ? ` ${address.postalCode}` : ""}
                 </p>
-                <p className="text-gray-600">{billingInfo.address.country}</p>
+                <p className="text-gray-600">{address.country}</p>
               </div>
 
               {/* Status message for Internet orders when pending */}
diff --git a/apps/portal/src/features/catalog/components/base/EnhancedOrderSummary.tsx b/apps/portal/src/features/catalog/components/base/EnhancedOrderSummary.tsx
index de0fc4d3..eaab284f 100644
--- a/apps/portal/src/features/catalog/components/base/EnhancedOrderSummary.tsx
+++ b/apps/portal/src/features/catalog/components/base/EnhancedOrderSummary.tsx
@@ -9,6 +9,7 @@ import {
 } from "@heroicons/react/24/outline";
 import { AnimatedCard } from "@/components/ui";
 import { Button } from "@/components/ui/button";
+import { useRouter } from "next/navigation";
 
 // Use consolidated domain types
 import type { 
@@ -105,6 +106,7 @@ export function EnhancedOrderSummary({
   headerContent,
   footerContent,
 }: EnhancedOrderSummaryProps) {
+  const router = useRouter();
   const sizeClasses = {
     compact: "p-4",
     standard: "p-6",
@@ -335,11 +337,13 @@ export function EnhancedOrderSummary({
         <div className="flex gap-4">
           {backUrl ? (
             <Button
-              as="a"
-              href={backUrl}
               variant="outline"
               className="flex-1 group"
               disabled={disabled || loading}
+              onClick={() => {
+                if (disabled || loading) return;
+                router.push(backUrl);
+              }}
             >
               <ArrowLeftIcon className="w-4 h-4 mr-2 group-hover:-translate-x-1 transition-transform duration-300" />
               {backLabel}
diff --git a/apps/portal/src/features/catalog/components/base/PaymentForm.tsx b/apps/portal/src/features/catalog/components/base/PaymentForm.tsx
index 0889a81b..dcfc1f80 100644
--- a/apps/portal/src/features/catalog/components/base/PaymentForm.tsx
+++ b/apps/portal/src/features/catalog/components/base/PaymentForm.tsx
@@ -1,44 +1,25 @@
 "use client";
 
+import { useEffect, useMemo, useState } from "react";
 import { Skeleton } from "@/components/ui/loading-skeleton";
 import { Button } from "@/components/ui/button";
 import { AlertBanner } from "@/components/common/AlertBanner";
-
-import { useState, useEffect } from "react";
-import {
-  CreditCardIcon,
-  ExclamationTriangleIcon,
-  CheckCircleIcon,
-} from "@heroicons/react/24/outline";
-
-// Use domain PaymentMethod type
+import { CreditCardIcon, CheckCircleIcon } from "@heroicons/react/24/outline";
 import type { PaymentMethod } from "@customer-portal/domain";
 
 export interface PaymentFormProps {
-  // Payment methods
   existingMethods?: PaymentMethod[];
   selectedMethodId?: string;
-
-  // Callbacks
   onMethodSelect?: (methodId: string) => void;
   onAddNewMethod?: () => void;
   onValidationChange?: (isValid: boolean, errors: string[]) => void;
-
-  // Configuration
   title?: string;
   description?: string;
   showTitle?: boolean;
   allowNewMethod?: boolean;
   requirePaymentMethod?: boolean;
-
-  // State
   loading?: boolean;
   disabled?: boolean;
-
-  // Styling
-  variant?: "default" | "compact" | "inline";
-
-  // Custom content
   children?: React.ReactNode;
   footerContent?: React.ReactNode;
 }
@@ -56,77 +37,41 @@ export function PaymentForm({
   requirePaymentMethod = true,
   loading = false,
   disabled = false,
-  variant = "default",
   children,
   footerContent,
 }: PaymentFormProps) {
-  const [selectedMethod, setSelectedMethod] = useState<string>(selectedMethodId || "");
+  const [selectedMethod, setSelectedMethod] = useState<string>(selectedMethodId ?? "");
   const [errors, setErrors] = useState<string[]>([]);
 
-  const validatePayment = () => {
-    const validationErrors: string[] = [];
-
-    if (requirePaymentMethod) {
-      if (existingMethods.length === 0) {
-        validationErrors.push(
-          "No payment method on file. Please add a payment method to continue."
-        );
-      } else if (!selectedMethod) {
-        validationErrors.push("Please select a payment method.");
-      }
-    }
-
-    setErrors(validationErrors);
-    const isValid = validationErrors.length === 0;
-    onValidationChange?.(isValid, validationErrors);
-
-    return isValid;
-  };
-
-  const handleMethodSelect = (methodId: string) => {
-    if (disabled) return;
-
-    setSelectedMethod(methodId);
-    onMethodSelect?.(methodId);
-  };
-
-  useEffect(() => {
-    validatePayment();
-  }, [selectedMethod, existingMethods, requirePaymentMethod]);
-
   useEffect(() => {
     if (selectedMethodId !== undefined) {
       setSelectedMethod(selectedMethodId);
     }
   }, [selectedMethodId]);
 
-  const getCardBrandIcon = (brand?: string) => {
-    // In a real implementation, you'd return appropriate brand icons
-    return <CreditCardIcon className="h-6 w-6 text-gray-400" />;
-  };
+  useEffect(() => {
+    const validationErrors: string[] = [];
 
-  const formatCardNumber = (last4?: string) => {
-    return last4 ? `•••• •••• •••• ${last4}` : "•••• •••• •••• ••••";
-  };
+    if (requirePaymentMethod) {
+      if (existingMethods.length === 0) {
+        validationErrors.push("No payment methods on file. Add one to continue.");
+      } else if (!selectedMethod) {
+        validationErrors.push("Select a payment method to continue.");
+      }
+    }
 
-  const formatExpiry = (month?: number, year?: number) => {
-    if (!month || !year) return "";
-    return `${month.toString().padStart(2, "0")}/${year.toString().slice(-2)}`;
-  };
+    setErrors(validationErrors);
+    onValidationChange?.(validationErrors.length === 0, validationErrors);
+  }, [existingMethods, requirePaymentMethod, selectedMethod, onValidationChange]);
 
-  const containerClasses =
-    variant === "inline"
-      ? ""
-      : variant === "compact"
-        ? "p-4 bg-gray-50 rounded-lg border border-gray-200"
-        : "p-6 bg-white border border-gray-200 rounded-lg";
+  const methods = useMemo(() => existingMethods, [existingMethods]);
 
   if (loading) {
     return (
-      <div className={containerClasses}>
+      <div className="p-6 bg-white border border-gray-200 rounded-lg">
         <div className="space-y-4">
-          {Array.from({ length: 2 }).map((_, i) => (
-            <div key={i} className="flex items-center justify-between">
+          {Array.from({ length: 2 }).map((_, index) => (
+            <div key={index} className="flex items-center justify-between">
               <div className="flex items-center gap-3">
                 <Skeleton className="h-8 w-12" />
                 <div className="space-y-2">
@@ -142,116 +87,118 @@ export function PaymentForm({
     );
   }
 
+  const renderMethod = (method: PaymentMethod) => {
+    const methodId = String(method.id);
+    const isSelected = selectedMethod === methodId;
+    const label = method.cardBrand
+      ? `${method.cardBrand.toUpperCase()} ${method.lastFour ? `•••• ${method.lastFour}` : ""}`.trim()
+      : method.description ?? method.type;
+
+    return (
+      <label
+        key={method.id}
+        className={[
+          "flex items-center justify-between p-4 border-2 rounded-lg cursor-pointer transition-colors",
+          isSelected ? "border-blue-500 bg-blue-50" : "border-gray-200 hover:border-gray-300",
+          disabled ? "opacity-50 cursor-not-allowed" : "",
+        ].join(" ")}
+      >
+        <div className="flex items-center gap-3">
+          <CreditCardIcon className="h-6 w-6 text-gray-400" />
+          <div>
+            <div className="text-sm font-medium text-gray-900 flex items-center gap-2">
+              {label}
+              {method.isDefault ? (
+                <span className="bg-green-100 text-green-800 text-xs px-2 py-1 rounded-full">Default</span>
+              ) : null}
+            </div>
+            {method.expiryDate ? (
+              <div className="text-xs text-gray-500">Expires {method.expiryDate}</div>
+            ) : null}
+          </div>
+        </div>
+
+        <input
+          type="radio"
+          name="paymentMethod"
+          value={methodId}
+          checked={isSelected}
+          disabled={disabled}
+          onChange={() => {
+            if (disabled) return;
+            setSelectedMethod(methodId);
+            onMethodSelect?.(methodId);
+          }}
+          className="text-blue-600 focus:ring-blue-500"
+        />
+      </label>
+    );
+  };
+
   return (
-    <div className={containerClasses}>
+    <div className="p-6 bg-white border border-gray-200 rounded-lg space-y-4">
       {showTitle && (
-        <div className="mb-6">
-          <div className="flex items-center gap-2 mb-2">
+        <div>
+          <div className="flex items-center gap-2 mb-1">
             <CreditCardIcon className="h-5 w-5 text-blue-600" />
             <h3 className="text-lg font-semibold text-gray-900">{title}</h3>
           </div>
-          {description && <p className="text-sm text-gray-600">{description}</p>}
+          {description ? <p className="text-sm text-gray-600">{description}</p> : null}
         </div>
       )}
 
-      {/* No payment methods */}
-      {existingMethods.length === 0 ? (
-        <div className="text-center py-8">
-          <div className="w-16 h-16 bg-gray-100 rounded-full flex items-center justify-center mx-auto mb-4">
-            <CreditCardIcon className="h-8 w-8 text-gray-400" />
+      {methods.length === 0 ? (
+        <div className="py-8 text-center">
+          <div className="mx-auto mb-4 flex h-12 w-12 items-center justify-center rounded-full bg-gray-100">
+            <CreditCardIcon className="h-6 w-6 text-gray-400" />
           </div>
-          <h4 className="text-lg font-medium text-gray-900 mb-2">No Payment Method on File</h4>
-          <p className="text-gray-600 mb-6">Add a payment method to complete your order.</p>
-          {allowNewMethod && onAddNewMethod && (
+          <p className="text-sm text-gray-600 mb-4">Add a payment method to continue.</p>
+          {allowNewMethod && onAddNewMethod ? (
             <Button onClick={onAddNewMethod} disabled={disabled}>
               Add Payment Method
             </Button>
-          )}
+          ) : null}
         </div>
       ) : (
-        <div className="space-y-4">
-          {/* Existing payment methods */}
-          <div className="space-y-3">
-            {existingMethods.map(method => (
-              <label
-                key={method.id}
-                className={`flex items-center p-4 border-2 rounded-lg cursor-pointer transition-all ${
-                  selectedMethod === method.id
-                    ? "border-blue-500 bg-blue-50 ring-2 ring-blue-100"
-                    : "border-gray-200 hover:border-gray-300 bg-white"
-                } ${disabled ? "opacity-50 cursor-not-allowed" : ""}`}
-              >
-                <input
-                  type="radio"
-                  name="paymentMethod"
-                  value={method.id}
-                  checked={selectedMethod === method.id}
-                  onChange={() => handleMethodSelect(method.id)}
-                  disabled={disabled}
-                  className="text-blue-600 focus:ring-blue-500 mr-4"
-                />
-
-                <div className="flex items-center flex-1">
-                  <div className="mr-4">{getCardBrandIcon(method.brand)}</div>
-
-                  <div className="flex-1">
-                    <div className="flex items-center gap-2">
-                      <span className="font-medium text-gray-900">
-                        {method.brand?.toUpperCase()} {formatCardNumber(method.last4)}
-                      </span>
-                      {method.isDefault && (
-                        <span className="bg-green-100 text-green-800 text-xs px-2 py-1 rounded-full font-medium">
-                          Default
-                        </span>
-                      )}
-                    </div>
-
-                    <div className="text-sm text-gray-600 mt-1">
-                      {method.name && <span>{method.name} • </span>}
-                      Expires {formatExpiry(method.expiryMonth, method.expiryYear)}
-                    </div>
-                  </div>
-
-                  {selectedMethod === method.id && (
-                    <CheckCircleIcon className="h-5 w-5 text-blue-600 ml-4" />
-                  )}
-                </div>
-              </label>
-            ))}
-          </div>
-
-          {/* Add new payment method option */}
-          {allowNewMethod && onAddNewMethod && (
-            <div className="pt-4 border-t border-gray-200">
-              <button
+        <div className="space-y-3">
+          {methods.map(renderMethod)}
+          {allowNewMethod && onAddNewMethod ? (
+            <div className="pt-3">
+              <Button
+                variant="outline"
+                className="w-full"
                 onClick={onAddNewMethod}
                 disabled={disabled}
-                className="w-full flex items-center justify-center gap-2 p-4 border-2 border-dashed border-gray-300 rounded-lg text-gray-600 hover:border-gray-400 hover:text-gray-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed"
               >
-                <CreditCardIcon className="h-5 w-5" />
-                <span className="font-medium">Add New Payment Method</span>
-              </button>
+                Add Another Method
+              </Button>
             </div>
-          )}
+          ) : null}
         </div>
       )}
 
-      {/* Custom content */}
-      {children && <div className="mt-6">{children}</div>}
+      {children}
 
-      {/* Validation errors */}
-      {errors.length > 0 && (
-        <AlertBanner variant="error" title="Payment Required" className="mt-4" elevated size="sm">
+      {errors.length > 0 ? (
+        <AlertBanner variant="error" title="Payment Required" elevated size="sm">
           <ul className="list-disc list-inside">
-            {errors.map((error, index) => (
-              <li key={index}>{error}</li>
+            {errors.map((msg, index) => (
+              <li key={index}>{msg}</li>
             ))}
           </ul>
         </AlertBanner>
+      ) : (
+        selectedMethod && (
+          <div className="flex items-center gap-2 text-sm text-green-600">
+            <CheckCircleIcon className="h-4 w-4" />
+            Payment method selected
+          </div>
+        )
       )}
 
-      {/* Footer content */}
-      {footerContent && <div className="mt-6 pt-4 border-t border-gray-200">{footerContent}</div>}
+      {footerContent ? (
+        <div className="pt-4 border-t border-gray-200">{footerContent}</div>
+      ) : null}
     </div>
   );
 }
diff --git a/apps/portal/src/features/catalog/services/catalog.service.ts b/apps/portal/src/features/catalog/services/catalog.service.ts
index 863d3ac7..c16d41d0 100644
--- a/apps/portal/src/features/catalog/services/catalog.service.ts
+++ b/apps/portal/src/features/catalog/services/catalog.service.ts
@@ -1,44 +1,45 @@
 import { apiClient } from "@/core/api";
+import { getDataOrDefault } from "@/core/api/response-helpers";
 import type { InternetProduct, SimProduct, VpnProduct } from "@customer-portal/domain";
 
 async function getInternetPlans(): Promise<InternetProduct[]> {
-  const response = await apiClient.GET("/catalog/internet/plans");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/internet/plans");
+  return getDataOrDefault(response, [] as InternetProduct[]);
 }
 
 async function getInternetInstallations(): Promise<InternetProduct[]> {
-  const response = await apiClient.GET("/catalog/internet/installations");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/internet/installations");
+  return getDataOrDefault(response, [] as InternetProduct[]);
 }
 
 async function getInternetAddons(): Promise<InternetProduct[]> {
-  const response = await apiClient.GET("/catalog/internet/addons");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/internet/addons");
+  return getDataOrDefault(response, [] as InternetProduct[]);
 }
 
 async function getSimPlans(): Promise<SimProduct[]> {
-  const response = await apiClient.GET("/catalog/sim/plans");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/sim/plans");
+  return getDataOrDefault(response, [] as SimProduct[]);
 }
 
 async function getSimActivationFees(): Promise<SimProduct[]> {
-  const response = await apiClient.GET("/catalog/sim/activation-fees");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/sim/activation-fees");
+  return getDataOrDefault(response, [] as SimProduct[]);
 }
 
 async function getSimAddons(): Promise<SimProduct[]> {
-  const response = await apiClient.GET("/catalog/sim/addons");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/sim/addons");
+  return getDataOrDefault(response, [] as SimProduct[]);
 }
 
 async function getVpnPlans(): Promise<VpnProduct[]> {
-  const response = await apiClient.GET("/catalog/vpn/plans");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/vpn/plans");
+  return getDataOrDefault(response, [] as VpnProduct[]);
 }
 
 async function getVpnActivationFees(): Promise<VpnProduct[]> {
-  const response = await apiClient.GET("/catalog/vpn/activation-fees");
-  return response.data ?? [];
+  const response = await apiClient.GET("/api/catalog/vpn/activation-fees");
+  return getDataOrDefault(response, [] as VpnProduct[]);
 }
 
 export const catalogService = {
diff --git a/apps/portal/src/features/dashboard/hooks/useDashboard.ts b/apps/portal/src/features/dashboard/hooks/useDashboard.ts
deleted file mode 100644
index 2833ddc6..00000000
--- a/apps/portal/src/features/dashboard/hooks/useDashboard.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-"use client";
-
-import { useQuery } from "@tanstack/react-query";
-import { apiClient, queryKeys } from "@/core/api";
-
-/**
- * Simplified Dashboard Hook - Just fetch formatted data from BFF
- */
-export function useDashboard() {
-  // Get dashboard summary (BFF returns formatted, aggregated data)
-  const summaryQuery = useQuery({
-    queryKey: queryKeys.dashboard.summary(),
-    queryFn: () => apiClient.GET('/dashboard/summary'),
-    staleTime: 2 * 60 * 1000, // 2 minutes (financial data should be fresh)
-  });
-
-  return {
-    // Dashboard summary with all stats pre-calculated by BFF
-    summary: summaryQuery.data?.data,
-    isLoading: summaryQuery.isLoading,
-    error: summaryQuery.error,
-    refetch: summaryQuery.refetch,
-  };
-}
-
-// Export the hook with the same name as before for compatibility
-export const useDashboardSummary = useDashboard;
diff --git a/apps/portal/src/features/dashboard/hooks/useDashboardSummary.ts b/apps/portal/src/features/dashboard/hooks/useDashboardSummary.ts
index 41e8f310..a27c6691 100644
--- a/apps/portal/src/features/dashboard/hooks/useDashboardSummary.ts
+++ b/apps/portal/src/features/dashboard/hooks/useDashboardSummary.ts
@@ -3,10 +3,14 @@
  * Provides dashboard data with proper error handling, caching, and loading states
  */
 
-import { useQuery, useQueryClient } from "@tanstack/react-query";
+import { useQuery } from "@tanstack/react-query";
 import { useAuthStore } from "@/features/auth/services/auth.store";
-import { apiClient } from "@/core/api";
-import type { DashboardSummary, DashboardError } from "@customer-portal/domain";
+import { apiClient, queryKeys } from "@/core/api";
+import { getDataOrThrow } from "@/core/api/response-helpers";
+import type {
+  DashboardSummary,
+  DashboardError,
+} from "@customer-portal/domain";
 
 class DashboardDataError extends Error {
   constructor(
@@ -19,14 +23,6 @@ class DashboardDataError extends Error {
   }
 }
 
-// Query key factory for dashboard queries
-export const dashboardQueryKeys = {
-  all: ["dashboard"] as const,
-  summary: () => [...dashboardQueryKeys.all, "summary"] as const,
-  stats: () => [...dashboardQueryKeys.all, "stats"] as const,
-  activity: (filters?: string[]) => [...dashboardQueryKeys.all, "activity", filters] as const,
-  nextInvoice: () => [...dashboardQueryKeys.all, "next-invoice"] as const,
-};
 
 /**
  * Hook for fetching dashboard summary data
@@ -35,7 +31,7 @@ export function useDashboardSummary() {
   const { isAuthenticated, tokens } = useAuthStore();
 
   return useQuery<DashboardSummary, DashboardError>({
-    queryKey: dashboardQueryKeys.summary(),
+    queryKey: queryKeys.dashboard.summary(),
     queryFn: async () => {
       if (!tokens?.accessToken) {
         throw new DashboardDataError(
@@ -45,8 +41,11 @@ export function useDashboardSummary() {
       }
 
       try {
-        const response = await apiClient.GET('/dashboard/summary');
-        return response.data!;
+        const response = await apiClient.GET('/api/dashboard/summary');
+        return getDataOrThrow<DashboardSummary>(
+          response,
+          "Dashboard summary response was empty"
+        );
       } catch (error) {
         // Transform API errors to DashboardError format
         if (error instanceof Error) {
@@ -77,97 +76,3 @@ export function useDashboardSummary() {
   });
 }
 
-/**
- * Hook for refreshing dashboard data
- */
-export function useRefreshDashboard() {
-  const queryClient = useQueryClient();
-  const { isAuthenticated, tokens } = useAuthStore();
-
-  const refreshDashboard = async () => {
-    if (!isAuthenticated || !tokens?.accessToken) {
-      throw new Error("Authentication required");
-    }
-
-    // Invalidate and refetch dashboard queries
-    await queryClient.invalidateQueries({
-      queryKey: dashboardQueryKeys.all,
-    });
-
-    // Optionally fetch fresh data immediately
-    return queryClient.fetchQuery({
-      queryKey: dashboardQueryKeys.summary(),
-      queryFn: async () => {
-        const response = await apiClient.POST('/dashboard/refresh');
-        return response.data!;
-      },
-    });
-  };
-
-  return { refreshDashboard };
-}
-
-/**
- * Hook for fetching dashboard stats only (lightweight)
- */
-export function useDashboardStats() {
-  const { isAuthenticated, tokens } = useAuthStore();
-
-  return useQuery({
-    queryKey: dashboardQueryKeys.stats(),
-    queryFn: async () => {
-      if (!tokens?.accessToken) {
-        throw new Error("Authentication required");
-      }
-      const response = await apiClient.GET('/dashboard/stats');
-      return response.data!;
-    },
-    staleTime: 1 * 60 * 1000, // 1 minute
-    gcTime: 3 * 60 * 1000, // 3 minutes
-    enabled: isAuthenticated && !!tokens?.accessToken,
-  });
-}
-
-/**
- * Hook for fetching recent activity with filtering
- */
-export function useDashboardActivity(filters?: string[], limit = 10) {
-  const { isAuthenticated, tokens } = useAuthStore();
-
-  return useQuery({
-    queryKey: dashboardQueryKeys.activity(filters),
-    queryFn: async () => {
-      if (!tokens?.accessToken) {
-        throw new Error("Authentication required");
-      }
-      const response = await apiClient.GET('/dashboard/activity', {
-        params: { query: { limit, filters: filters?.join(',') } }
-      });
-      return response.data!;
-    },
-    staleTime: 30 * 1000, // 30 seconds
-    gcTime: 2 * 60 * 1000, // 2 minutes
-    enabled: isAuthenticated && !!tokens?.accessToken,
-  });
-}
-
-/**
- * Hook for fetching next invoice information
- */
-export function useNextInvoice() {
-  const { isAuthenticated, tokens } = useAuthStore();
-
-  return useQuery({
-    queryKey: dashboardQueryKeys.nextInvoice(),
-    queryFn: async () => {
-      if (!tokens?.accessToken) {
-        throw new Error("Authentication required");
-      }
-      const response = await apiClient.GET('/dashboard/next-invoice');
-      return response.data!;
-    },
-    staleTime: 5 * 60 * 1000, // 5 minutes
-    gcTime: 10 * 60 * 1000, // 10 minutes
-    enabled: isAuthenticated && !!tokens?.accessToken,
-  });
-}
diff --git a/apps/portal/src/features/orders/services/orders.service.ts b/apps/portal/src/features/orders/services/orders.service.ts
index 961e9d07..6b45bc5b 100644
--- a/apps/portal/src/features/orders/services/orders.service.ts
+++ b/apps/portal/src/features/orders/services/orders.service.ts
@@ -7,7 +7,7 @@ export interface CreateOrderRequest {
 }
 
 async function createOrder<T = { sfOrderId: string }>(payload: CreateOrderRequest): Promise<T> {
-  const response = await apiClient.POST("/orders", { body: payload });
+  const response = await apiClient.POST("/api/orders", { body: payload });
   if (!response.data) {
     throw new Error("Order creation failed");
   }
@@ -15,12 +15,12 @@ async function createOrder<T = { sfOrderId: string }>(payload: CreateOrderReques
 }
 
 async function getMyOrders<T = unknown[]>(): Promise<T> {
-  const response = await apiClient.GET("/orders/user");
+  const response = await apiClient.GET("/api/orders/user");
   return (response.data ?? []) as T;
 }
 
 async function getOrderById<T = unknown>(orderId: string): Promise<T> {
-  const response = await apiClient.GET("/orders/{sfOrderId}", {
+  const response = await apiClient.GET("/api/orders/{sfOrderId}", {
     params: { path: { sfOrderId: orderId } },
   });
   if (!response.data) {
diff --git a/apps/portal/src/features/sim-management/components/ChangePlanModal.tsx b/apps/portal/src/features/sim-management/components/ChangePlanModal.tsx
index 06c4b157..364dc49e 100644
--- a/apps/portal/src/features/sim-management/components/ChangePlanModal.tsx
+++ b/apps/portal/src/features/sim-management/components/ChangePlanModal.tsx
@@ -42,7 +42,7 @@ export function ChangePlanModal({
     }
     setLoading(true);
     try {
-      await apiClient.POST("/subscriptions/{id}/sim/change-plan", {
+      await apiClient.POST("/api/subscriptions/{id}/sim/change-plan", {
         params: { path: { id: subscriptionId } },
         body: {
           newPlanCode,
diff --git a/apps/portal/src/features/sim-management/components/SimActions.tsx b/apps/portal/src/features/sim-management/components/SimActions.tsx
index 5b436065..17c11462 100644
--- a/apps/portal/src/features/sim-management/components/SimActions.tsx
+++ b/apps/portal/src/features/sim-management/components/SimActions.tsx
@@ -58,7 +58,7 @@ export function SimActions({
     setError(null);
 
     try {
-      await apiClient.POST("/subscriptions/{id}/sim/reissue-esim", {
+      await apiClient.POST("/api/subscriptions/{id}/sim/reissue-esim", {
         params: { path: { id: subscriptionId } },
       });
 
@@ -77,7 +77,7 @@ export function SimActions({
     setError(null);
 
     try {
-      await apiClient.POST("/subscriptions/{id}/sim/cancel", {
+      await apiClient.POST("/api/subscriptions/{id}/sim/cancel", {
         params: { path: { id: subscriptionId } },
       });
 
diff --git a/apps/portal/src/features/sim-management/components/SimFeatureToggles.tsx b/apps/portal/src/features/sim-management/components/SimFeatureToggles.tsx
index 6ad58384..5de5c9e7 100644
--- a/apps/portal/src/features/sim-management/components/SimFeatureToggles.tsx
+++ b/apps/portal/src/features/sim-management/components/SimFeatureToggles.tsx
@@ -75,7 +75,7 @@ export function SimFeatureToggles({
       if (nt !== initial.nt) featurePayload.networkType = nt;
 
       if (Object.keys(featurePayload).length > 0) {
-        await apiClient.POST("/subscriptions/{id}/sim/features", {
+        await apiClient.POST("/api/subscriptions/{id}/sim/features", {
           params: { path: { id: subscriptionId } },
           body: featurePayload,
         });
diff --git a/apps/portal/src/features/sim-management/components/SimManagementSection.tsx b/apps/portal/src/features/sim-management/components/SimManagementSection.tsx
index 741dbf39..7d3c6ec7 100644
--- a/apps/portal/src/features/sim-management/components/SimManagementSection.tsx
+++ b/apps/portal/src/features/sim-management/components/SimManagementSection.tsx
@@ -30,7 +30,7 @@ export function SimManagementSection({ subscriptionId }: SimManagementSectionPro
     try {
       setError(null);
 
-      const response = await apiClient.GET("/subscriptions/{id}/sim", {
+      const response = await apiClient.GET("/api/subscriptions/{id}/sim", {
         params: { path: { id: subscriptionId } },
       });
 
diff --git a/apps/portal/src/features/sim-management/components/TopUpModal.tsx b/apps/portal/src/features/sim-management/components/TopUpModal.tsx
index da0b7bbc..ae005956 100644
--- a/apps/portal/src/features/sim-management/components/TopUpModal.tsx
+++ b/apps/portal/src/features/sim-management/components/TopUpModal.tsx
@@ -45,7 +45,7 @@ export function TopUpModal({ subscriptionId, onClose, onSuccess, onError }: TopU
         quotaMb: getCurrentAmountMb(),
       };
 
-      await apiClient.POST("/subscriptions/{id}/sim/top-up", {
+      await apiClient.POST("/api/subscriptions/{id}/sim/top-up", {
         params: { path: { id: subscriptionId } },
         body: requestBody,
       });
diff --git a/apps/portal/src/features/subscriptions/components/SubscriptionActions.tsx b/apps/portal/src/features/subscriptions/components/SubscriptionActions.tsx
deleted file mode 100644
index c03c8b15..00000000
--- a/apps/portal/src/features/subscriptions/components/SubscriptionActions.tsx
+++ /dev/null
@@ -1,307 +0,0 @@
-"use client";
-
-import { useState } from "react";
-import { useRouter } from "next/navigation";
-import {
-  PauseIcon,
-  PlayIcon,
-  XMarkIcon,
-  ArrowUpIcon,
-  ArrowDownIcon,
-  DocumentTextIcon,
-  CreditCardIcon,
-  Cog6ToothIcon,
-  ExclamationTriangleIcon,
-} from "@heroicons/react/24/outline";
-import { Button } from "@/components/ui/button";
-import { SubCard } from "@/components/ui/sub-card";
-import type { Subscription } from "@customer-portal/domain";
-import { cn } from "@/shared/utils";
-import { useSubscriptionAction } from "../hooks";
-
-interface SubscriptionActionsProps {
-  subscription: Subscription;
-  onActionSuccess?: () => void;
-  className?: string;
-}
-
-interface ActionButtonProps {
-  icon: React.ReactNode;
-  label: string;
-  description: string;
-  variant?: "default" | "destructive" | "outline" | "secondary";
-  disabled?: boolean;
-  onClick: () => void;
-}
-
-const ActionButton = ({
-  icon,
-  label,
-  description,
-  variant = "outline",
-  disabled,
-  onClick,
-}: ActionButtonProps) => (
-  <div className="flex items-start space-x-3 p-4 border border-gray-200 rounded-lg hover:border-gray-300 transition-colors">
-    <div className="flex-shrink-0 mt-1">{icon}</div>
-    <div className="flex-1 min-w-0">
-      <h4 className="text-sm font-semibold text-gray-900">{label}</h4>
-      <p className="text-sm text-gray-600 mt-1">{description}</p>
-    </div>
-    <div className="flex-shrink-0">
-      <Button variant={variant} size="sm" disabled={disabled} onClick={onClick}>
-        {label}
-      </Button>
-    </div>
-  </div>
-);
-
-export function SubscriptionActions({
-  subscription,
-  onActionSuccess,
-  className,
-}: SubscriptionActionsProps) {
-  const router = useRouter();
-  const [loading, setLoading] = useState<string | null>(null);
-  const subscriptionAction = useSubscriptionAction();
-
-  const isActive = subscription.status === "Active";
-  const isSuspended = subscription.status === "Suspended";
-  const isCancelled = subscription.status === "Cancelled" || subscription.status === "Terminated";
-  const isPending = subscription.status === "Pending";
-
-  const isSimService = subscription.productName.toLowerCase().includes("sim");
-  const isInternetService =
-    subscription.productName.toLowerCase().includes("internet") ||
-    subscription.productName.toLowerCase().includes("broadband") ||
-    subscription.productName.toLowerCase().includes("fiber");
-  const isVpnService = subscription.productName.toLowerCase().includes("vpn");
-
-  const handleSuspend = async () => {
-    setLoading("suspend");
-    try {
-      await subscriptionAction.mutateAsync({
-        id: subscription.id,
-        action: "suspend",
-      });
-      onActionSuccess?.();
-    } catch (error) {
-      console.error("Failed to suspend subscription:", error);
-    } finally {
-      setLoading(null);
-    }
-  };
-
-  const handleResume = async () => {
-    setLoading("resume");
-    try {
-      await subscriptionAction.mutateAsync({
-        id: subscription.id,
-        action: "resume",
-      });
-      onActionSuccess?.();
-    } catch (error) {
-      console.error("Failed to resume subscription:", error);
-    } finally {
-      setLoading(null);
-    }
-  };
-
-  const handleCancel = async () => {
-    if (
-      !confirm("Are you sure you want to cancel this subscription? This action cannot be undone.")
-    ) {
-      return;
-    }
-
-    setLoading("cancel");
-    try {
-      await subscriptionAction.mutateAsync({
-        id: subscription.id,
-        action: "cancel",
-      });
-      onActionSuccess?.();
-    } catch (error) {
-      console.error("Failed to cancel subscription:", error);
-    } finally {
-      setLoading(null);
-    }
-  };
-
-  const handleUpgrade = () => {
-    router.push(`/catalog?upgrade=${subscription.id}`);
-  };
-
-  const handleDowngrade = () => {
-    router.push(`/catalog?downgrade=${subscription.id}`);
-  };
-
-  const handleViewInvoices = () => {
-    router.push(`/subscriptions/${subscription.id}#billing`);
-  };
-
-  const handleManagePayment = () => {
-    router.push("/billing/payments");
-  };
-
-  const handleSimManagement = () => {
-    router.push(`/subscriptions/${subscription.id}#sim-management`);
-  };
-
-  const handleServiceSettings = () => {
-    router.push(`/subscriptions/${subscription.id}/settings`);
-  };
-
-  return (
-    <SubCard
-      title="Subscription Actions"
-      icon={<Cog6ToothIcon className="h-5 w-5" />}
-      className={cn("", className)}
-    >
-      <div className="space-y-4">
-        {/* Service Management Actions */}
-        <div>
-          <h4 className="text-sm font-medium text-gray-700 mb-3">Service Management</h4>
-          <div className="space-y-3">
-            {/* SIM Management - Only for SIM services */}
-            {isSimService && isActive && (
-              <ActionButton
-                icon={<Cog6ToothIcon className="h-5 w-5 text-blue-600" />}
-                label="SIM Management"
-                description="Manage data usage, top-up, and SIM settings"
-                onClick={handleSimManagement}
-              />
-            )}
-
-            {/* Service Settings - Available for all active services */}
-            {isActive && (
-              <ActionButton
-                icon={<Cog6ToothIcon className="h-5 w-5 text-gray-600" />}
-                label="Service Settings"
-                description="Configure service-specific settings and preferences"
-                onClick={handleServiceSettings}
-              />
-            )}
-
-            {/* Suspend/Resume Actions */}
-            {isActive && (
-              <ActionButton
-                icon={<PauseIcon className="h-5 w-5 text-yellow-600" />}
-                label="Suspend Service"
-                description="Temporarily suspend this service"
-                variant="outline"
-                onClick={() => {
-                  void handleSuspend();
-                }}
-                disabled={loading === "suspend"}
-              />
-            )}
-
-            {isSuspended && (
-              <ActionButton
-                icon={<PlayIcon className="h-5 w-5 text-green-600" />}
-                label="Resume Service"
-                description="Resume suspended service"
-                variant="outline"
-                onClick={() => {
-                  void handleResume();
-                }}
-                disabled={loading === "resume"}
-              />
-            )}
-          </div>
-        </div>
-
-        {/* Plan Management Actions */}
-        {(isActive || isSuspended) && !subscription.cycle.includes("One-time") && (
-          <div>
-            <h4 className="text-sm font-medium text-gray-700 mb-3">Plan Management</h4>
-            <div className="space-y-3">
-              <ActionButton
-                icon={<ArrowUpIcon className="h-5 w-5 text-green-600" />}
-                label="Upgrade Plan"
-                description="Upgrade to a higher tier plan with more features"
-                onClick={handleUpgrade}
-              />
-
-              <ActionButton
-                icon={<ArrowDownIcon className="h-5 w-5 text-blue-600" />}
-                label="Downgrade Plan"
-                description="Switch to a lower tier plan"
-                onClick={handleDowngrade}
-              />
-            </div>
-          </div>
-        )}
-
-        {/* Billing Actions */}
-        <div>
-          <h4 className="text-sm font-medium text-gray-700 mb-3">Billing & Payment</h4>
-          <div className="space-y-3">
-            <ActionButton
-              icon={<DocumentTextIcon className="h-5 w-5 text-gray-600" />}
-              label="View Invoices"
-              description="View billing history and download invoices"
-              onClick={handleViewInvoices}
-            />
-
-            <ActionButton
-              icon={<CreditCardIcon className="h-5 w-5 text-gray-600" />}
-              label="Manage Payment"
-              description="Update payment methods and billing information"
-              onClick={handleManagePayment}
-            />
-          </div>
-        </div>
-
-        {/* Cancellation Actions */}
-        {!isCancelled && !isPending && (
-          <div>
-            <h4 className="text-sm font-medium text-gray-700 mb-3">Cancellation</h4>
-            <div className="bg-red-50 border border-red-200 rounded-lg p-4">
-              <div className="flex items-start space-x-3">
-                <ExclamationTriangleIcon className="h-5 w-5 text-red-600 mt-0.5" />
-                <div className="flex-1">
-                  <h5 className="text-sm font-semibold text-red-900 mb-1">Cancel Subscription</h5>
-                  <p className="text-sm text-red-800 mb-3">
-                    Permanently cancel this subscription. This action cannot be undone and you will
-                    lose access to the service.
-                  </p>
-                  <Button
-                    variant="destructive"
-                    size="sm"
-                    onClick={() => {
-                      void handleCancel();
-                    }}
-                    loading={loading === "cancel"}
-                    loadingText="Cancelling..."
-                    leftIcon={<XMarkIcon className="h-4 w-4" />}
-                  >
-                    Cancel Subscription
-                  </Button>
-                </div>
-              </div>
-            </div>
-          </div>
-        )}
-
-        {/* Status Information */}
-        {(isCancelled || isPending) && (
-          <div className="bg-gray-50 border border-gray-200 rounded-lg p-4">
-            <div className="flex items-center space-x-2">
-              <ExclamationTriangleIcon className="h-5 w-5 text-gray-600" />
-              <h5 className="text-sm font-semibold text-gray-900">
-                {isCancelled ? "Subscription Cancelled" : "Subscription Pending"}
-              </h5>
-            </div>
-            <p className="text-sm text-gray-700 mt-2">
-              {isCancelled
-                ? "This subscription has been cancelled and is no longer active. No further actions are available."
-                : "This subscription is pending activation. Actions will be available once the subscription is active."}
-            </p>
-          </div>
-        )}
-      </div>
-    </SubCard>
-  );
-}
diff --git a/apps/portal/src/features/subscriptions/hooks/useSubscriptions.ts b/apps/portal/src/features/subscriptions/hooks/useSubscriptions.ts
index 55e0045f..62aa8ee0 100644
--- a/apps/portal/src/features/subscriptions/hooks/useSubscriptions.ts
+++ b/apps/portal/src/features/subscriptions/hooks/useSubscriptions.ts
@@ -3,8 +3,9 @@
  * React hooks for subscription functionality using shared types
  */
 
-import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useQuery } from "@tanstack/react-query";
 import { apiClient, queryKeys } from "@/core/api";
+import { getDataOrDefault, getDataOrThrow, getNullableData } from "@/core/api/response-helpers";
 import { useAuthSession } from "@/features/auth/services/auth.store";
 import type { InvoiceList, Subscription, SubscriptionList } from "@customer-portal/domain";
 
@@ -57,13 +58,12 @@ export function useSubscriptions(options: UseSubscriptionsOptions = {}) {
   const { isAuthenticated, hasValidToken } = useAuthSession();
 
   return useQuery<SubscriptionList>({
-    queryKey: queryKeys.subscriptions.list(status ? { status } : {}),
+    queryKey: queryKeys.subscriptions.list(status ? { status } : undefined),
     queryFn: async () => {
-      const response = await apiClient.GET(
-        "/subscriptions",
+      const response = await apiClient.GET("/api/subscriptions",
         status ? { params: { query: { status } } } : undefined
       );
-      return toSubscriptionList(response.data);
+      return toSubscriptionList(getNullableData(response));
     },
     staleTime: 5 * 60 * 1000,
     gcTime: 10 * 60 * 1000,
@@ -78,10 +78,10 @@ export function useActiveSubscriptions() {
   const { isAuthenticated, hasValidToken } = useAuthSession();
 
   return useQuery<Subscription[]>({
-    queryKey: [...queryKeys.subscriptions.all, "active"] as const,
+    queryKey: queryKeys.subscriptions.active(),
     queryFn: async () => {
-      const response = await apiClient.GET("/subscriptions/active");
-      return response.data ?? [];
+      const response = await apiClient.GET("/api/subscriptions/active");
+      return getDataOrDefault(response, [] as Subscription[]);
     },
     staleTime: 5 * 60 * 1000,
     gcTime: 10 * 60 * 1000,
@@ -98,8 +98,8 @@ export function useSubscriptionStats() {
   return useQuery({
     queryKey: queryKeys.subscriptions.stats(),
     queryFn: async () => {
-      const response = await apiClient.GET("/subscriptions/stats");
-      return response.data ?? emptyStats;
+      const response = await apiClient.GET("/api/subscriptions/stats");
+      return getDataOrDefault(response, emptyStats);
     },
     staleTime: 5 * 60 * 1000,
     gcTime: 10 * 60 * 1000,
@@ -116,13 +116,10 @@ export function useSubscription(subscriptionId: number) {
   return useQuery<Subscription>({
     queryKey: queryKeys.subscriptions.detail(String(subscriptionId)),
     queryFn: async () => {
-      const response = await apiClient.GET("/subscriptions/{id}", {
+      const response = await apiClient.GET("/api/subscriptions/{id}", {
         params: { path: { id: subscriptionId } },
       });
-      if (!response.data) {
-        throw new Error("Subscription not found");
-      }
-      return response.data;
+      return getDataOrThrow<Subscription>(response, "Subscription not found");
     },
     staleTime: 5 * 60 * 1000,
     gcTime: 10 * 60 * 1000,
@@ -143,44 +140,22 @@ export function useSubscriptionInvoices(
   return useQuery<InvoiceList>({
     queryKey: queryKeys.subscriptions.invoices(subscriptionId, { page, limit }),
     queryFn: async () => {
-      const response = await apiClient.GET("/subscriptions/{id}/invoices", {
+      const response = await apiClient.GET("/api/subscriptions/{id}/invoices", {
         params: {
           path: { id: subscriptionId },
           query: { page, limit },
         },
       });
-      if (!response.data) {
-        return {
-          ...emptyInvoiceList,
-          pagination: {
-            ...emptyInvoiceList.pagination,
-            page,
-          },
-        };
-      }
-      return response.data;
+      return getDataOrDefault(response, {
+        ...emptyInvoiceList,
+        pagination: {
+          ...emptyInvoiceList.pagination,
+          page,
+        },
+      });
     },
     staleTime: 60 * 1000,
     gcTime: 5 * 60 * 1000,
     enabled: isAuthenticated && hasValidToken && subscriptionId > 0,
   });
 }
-
-/**
- * Hook to perform subscription actions (suspend, resume, cancel, etc.)
- */
-export function useSubscriptionAction() {
-  const queryClient = useQueryClient();
-
-  return useMutation({
-    mutationFn: async ({ id, action }: { id: number; action: string }) => {
-      await apiClient.POST("/subscriptions/{id}/actions", {
-        params: { path: { id } },
-        body: { action },
-      });
-    },
-    onSuccess: async () => {
-      await queryClient.invalidateQueries({ queryKey: queryKeys.subscriptions.all });
-    },
-  });
-}
diff --git a/packages/api-client/src/index.ts b/packages/api-client/src/index.ts
index a9ba5fb9..5607326e 100644
--- a/packages/api-client/src/index.ts
+++ b/packages/api-client/src/index.ts
@@ -1,5 +1,5 @@
 export * as ApiTypes from "./__generated__/types";
-export { createClient } from "./runtime/client";
+export { createClient, resolveBaseUrl } from "./runtime/client";
 export type {
   ApiClient,
   AuthHeaderResolver,
diff --git a/packages/api-client/src/runtime/client.ts b/packages/api-client/src/runtime/client.ts
index 5f4fbeb0..eae08ec1 100644
--- a/packages/api-client/src/runtime/client.ts
+++ b/packages/api-client/src/runtime/client.ts
@@ -1,6 +1,9 @@
 import createOpenApiClient from "openapi-fetch";
+import type {
+  Middleware,
+  MiddlewareCallbackParams,
+} from "openapi-fetch";
 import type { paths } from "../__generated__/types";
-
 export class ApiError extends Error {
   constructor(
     message: string,
@@ -12,11 +15,72 @@ export class ApiError extends Error {
   }
 }
 
-export type ApiClient = ReturnType<typeof createOpenApiClient<paths>>;
+type StrictApiClient = ReturnType<typeof createOpenApiClient<paths>>;
+
+type FlexibleApiMethods = {
+  GET<T = unknown>(path: string, options?: unknown): Promise<{ data?: T | null }>;
+  POST<T = unknown>(path: string, options?: unknown): Promise<{ data?: T | null }>;
+  PUT<T = unknown>(path: string, options?: unknown): Promise<{ data?: T | null }>;
+  PATCH<T = unknown>(path: string, options?: unknown): Promise<{ data?: T | null }>;
+  DELETE<T = unknown>(path: string, options?: unknown): Promise<{ data?: T | null }>;
+};
+
+export type ApiClient = StrictApiClient & FlexibleApiMethods;
 
 export type AuthHeaderResolver = () => string | undefined;
 
+type EnvKey =
+  | "NEXT_PUBLIC_API_BASE"
+  | "NEXT_PUBLIC_API_URL"
+  | "API_BASE_URL"
+  | "API_BASE"
+  | "API_URL";
+
+const BASE_URL_ENV_KEYS: readonly EnvKey[] = [
+  "NEXT_PUBLIC_API_BASE",
+  "NEXT_PUBLIC_API_URL",
+  "API_BASE_URL",
+  "API_BASE",
+  "API_URL",
+];
+
+const DEFAULT_BASE_URL = "http://localhost:4000/api";
+
+const normalizeBaseUrl = (value: string) => {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return DEFAULT_BASE_URL;
+  }
+
+  if (trimmed === "/") {
+    return trimmed;
+  }
+
+  // Avoid accidental double slashes when openapi-fetch joins with request path
+  return trimmed.replace(/\/+$/, "");
+};
+
+const resolveBaseUrlFromEnv = () => {
+  for (const key of BASE_URL_ENV_KEYS) {
+    const envValue = process.env?.[key];
+    if (typeof envValue === "string" && envValue.trim()) {
+      return normalizeBaseUrl(envValue);
+    }
+  }
+
+  return DEFAULT_BASE_URL;
+};
+
+export const resolveBaseUrl = (baseUrl?: string) => {
+  if (typeof baseUrl === "string" && baseUrl.trim()) {
+    return normalizeBaseUrl(baseUrl);
+  }
+
+  return resolveBaseUrlFromEnv();
+};
+
 export interface CreateClientOptions {
+  baseUrl?: string;
   getAuthHeader?: AuthHeaderResolver;
   handleError?: (response: Response) => void | Promise<void>;
 }
@@ -49,10 +113,8 @@ async function defaultHandleError(response: Response) {
   throw new ApiError(message, response, body);
 }
 
-export function createClient(
-  baseUrl: string,
-  options: CreateClientOptions = {}
-): ApiClient {
+export function createClient(options: CreateClientOptions = {}): ApiClient {
+  const baseUrl = resolveBaseUrl(options.baseUrl);
   const client = createOpenApiClient<paths>({ baseUrl });
 
   const handleError = options.handleError ?? defaultHandleError;
@@ -60,8 +122,8 @@ export function createClient(
   if (typeof client.use === "function") {
     const resolveAuthHeader = options.getAuthHeader;
 
-    client.use({
-      onRequest({ request }) {
+    const middleware: Middleware = {
+      onRequest({ request }: MiddlewareCallbackParams) {
         if (!resolveAuthHeader) return;
         if (!request || typeof request.headers?.has !== "function") return;
         if (request.headers.has("Authorization")) return;
@@ -71,13 +133,15 @@ export function createClient(
 
         request.headers.set("Authorization", headerValue);
       },
-      async onResponse({ response }) {
+      async onResponse({ response }: MiddlewareCallbackParams & { response: Response }) {
         await handleError(response);
       },
-    } as never);
+    };
+
+    client.use(middleware as never);
   }
 
-  return client;
+  return client as ApiClient;
 }
 
 export type { paths };
diff --git a/packages/domain/src/utils/currency.ts b/packages/domain/src/utils/currency.ts
new file mode 100644
index 00000000..ec3303ea
--- /dev/null
+++ b/packages/domain/src/utils/currency.ts
@@ -0,0 +1,44 @@
+const DEFAULT_CURRENCY_LOCALE = "en-US";
+
+const currencyLocaleMap: Record<string, string> = {
+  USD: "en-US",
+  EUR: "de-DE",
+  GBP: "en-GB",
+  JPY: "ja-JP",
+  AUD: "en-AU",
+  CAD: "en-CA",
+};
+
+export interface FormatCurrencyOptions {
+  currency: string;
+  locale?: string;
+  minimumFractionDigits?: number;
+  maximumFractionDigits?: number;
+}
+
+export const getCurrencyLocale = (currency: string): string =>
+  currencyLocaleMap[currency.toUpperCase()] ?? DEFAULT_CURRENCY_LOCALE;
+
+export const formatCurrency = (
+  amount: number,
+  currencyOrOptions: string | FormatCurrencyOptions = "JPY"
+): string => {
+  const options =
+    typeof currencyOrOptions === "string"
+      ? { currency: currencyOrOptions }
+      : currencyOrOptions;
+
+  const {
+    currency,
+    locale = getCurrencyLocale(options.currency),
+    minimumFractionDigits,
+    maximumFractionDigits,
+  } = options;
+
+  return new Intl.NumberFormat(locale, {
+    style: "currency",
+    currency,
+    minimumFractionDigits,
+    maximumFractionDigits,
+  }).format(amount);
+};
diff --git a/packages/domain/src/utils/index.ts b/packages/domain/src/utils/index.ts
index 6c4d23d6..e8fe893e 100644
--- a/packages/domain/src/utils/index.ts
+++ b/packages/domain/src/utils/index.ts
@@ -2,4 +2,4 @@
 export * from "./validation";
 export * from "./array-utils";
 export * from "./filters";
-
+export * from "./currency";
diff --git a/packages/domain/src/utils/validation.ts b/packages/domain/src/utils/validation.ts
index da5d327d..390d119d 100644
--- a/packages/domain/src/utils/validation.ts
+++ b/packages/domain/src/utils/validation.ts
@@ -103,16 +103,6 @@ export function sanitizeString(input: string): string {
     .trim();
 }
 
-/**
- * Formats currency amount
- */
-export function formatCurrency(amount: number, currency = "JPY"): string {
-  return new Intl.NumberFormat("ja-JP", {
-    style: "currency",
-    currency,
-  }).format(amount);
-}
-
 /**
  * Formats date to locale string
  */