diff --git a/web/src/pages/admin/customers/CustomerManagementPage.tsx b/web/src/pages/admin/customers/CustomerManagementPage.tsx
index bd6a515..aa6b26a 100644
--- a/web/src/pages/admin/customers/CustomerManagementPage.tsx
+++ b/web/src/pages/admin/customers/CustomerManagementPage.tsx
@@ -1,5 +1,6 @@
 import { useState } from 'react';
-import { useQuery, useMutation } from '@tanstack/react-query';
+import { useForm } from 'react-hook-form';
+import { zodResolver } from '@hookform/resolvers/zod';
 import {
   Box,
   Typography,
@@ -28,33 +29,23 @@ import SearchIcon from '@mui/icons-material/Search';
 import AddIcon from '@mui/icons-material/Add';
 import EditIcon from '@mui/icons-material/Edit';
 import ErrorOutlineIcon from '@mui/icons-material/ErrorOutlined';
-import { toast } from 'react-toastify';
 import {
-  customersApi,
-  type Customer,
-  type PagedCustomerResponse,
-  type CreateCustomerRequest,
-  type UpdateCustomerRequest,
-} from '../../../lib/api/customers';
-import { queryClient } from '../../../lib/queryClient';
-import { QUERY_KEYS } from '../../../constants/queryKeys';
+  useCustomerList,
+  useCreateCustomer,
+  useUpdateCustomer,
+} from '../../../domain/customers/use-cases';
+import type { Customer } from '../../../domain/customers/types';
+import {
+  customerFormSchema,
+  toCustomerRequest,
+  type CustomerFormValues,
+} from '../../../domain/customers/schemas';
 import { DEFAULT_PAGE, DEFAULT_PAGE_SIZE, DEBOUNCE_SEARCH } from '../../../constants';
 import { useDocumentTitle } from '../../../hooks/useDocumentTitle';
 
 const COL_COUNT = 4; // Name, Address, Contact Email, Actions
 
-/** Simple email format check (client-side only). */
-function isValidEmail(email: string): boolean {
-  return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
-}
-
-interface CustomerFormState {
-  name: string;
-  address: string;
-  contactEmail: string;
-}
-
-const EMPTY_FORM: CustomerFormState = { name: '', address: '', contactEmail: '' };
+const EMPTY_FORM: CustomerFormValues = { name: '', address: '', contactEmail: '' };
 
 export default function CustomerManagementPage() {
   useDocumentTitle('Customer Management');
@@ -78,14 +69,10 @@ export default function CustomerManagementPage() {
     setDebounceTimer(timer);
   };
 
-  const {
-    data,
-    isLoading,
-    isError,
-    refetch,
-  } = useQuery<PagedCustomerResponse>({
-    queryKey: [QUERY_KEYS.customerList, debouncedSearch, page, pageSize],
-    queryFn: () => customersApi.list({ search: debouncedSearch || undefined, page, pageSize }),
+  const { data, isLoading, isError, refetch } = useCustomerList({
+    search: debouncedSearch || undefined,
+    page,
+    pageSize,
   });
 
   const rows = data?.items ?? [];
@@ -94,101 +81,59 @@ export default function CustomerManagementPage() {
   // --- Dialog state ---
   const [dialogOpen, setDialogOpen] = useState(false);
   const [editingCustomer, setEditingCustomer] = useState<Customer | null>(null);
-  const [form, setForm] = useState<CustomerFormState>(EMPTY_FORM);
-  const [formErrors, setFormErrors] = useState<Partial<Record<keyof CustomerFormState, string>>>({});
 
   const isEditing = editingCustomer !== null;
 
+  const {
+    register,
+    handleSubmit,
+    reset,
+    formState: { errors },
+  } = useForm<CustomerFormValues>({
+    resolver: zodResolver(customerFormSchema),
+    defaultValues: EMPTY_FORM,
+  });
+
   const openCreateDialog = () => {
     setEditingCustomer(null);
-    setForm(EMPTY_FORM);
-    setFormErrors({});
+    reset(EMPTY_FORM);
     setDialogOpen(true);
   };
 
   const openEditDialog = (customer: Customer) => {
     setEditingCustomer(customer);
-    setForm({
+    reset({
       name: customer.name,
       address: customer.addresses?.[0] ?? '',
       contactEmail: customer.contactEmail ?? '',
     });
-    setFormErrors({});
     setDialogOpen(true);
   };
 
   const closeDialog = () => {
     setDialogOpen(false);
     setEditingCustomer(null);
-    setForm(EMPTY_FORM);
-    setFormErrors({});
+    reset(EMPTY_FORM);
   };
 
-  const validateForm = (): boolean => {
-    const errors: Partial<Record<keyof CustomerFormState, string>> = {};
-    if (!form.name.trim()) errors.name = 'Name is required';
-    if (!form.address.trim()) errors.address = 'Address is required';
-    if (form.contactEmail.trim() && !isValidEmail(form.contactEmail.trim())) {
-      errors.contactEmail = 'Enter a valid email address';
-    }
-    setFormErrors(errors);
-    return Object.keys(errors).length === 0;
-  };
-
-  const handleFieldChange = (field: keyof CustomerFormState, value: string) => {
-    setForm((prev) => ({ ...prev, [field]: value }));
-    // Clear field error on change
-    if (formErrors[field]) {
-      setFormErrors((prev) => {
-        const next = { ...prev };
-        delete next[field];
-        return next;
-      });
-    }
-  };
-
-  // --- Mutations ---
-  const createMutation = useMutation({
-    mutationFn: (data: CreateCustomerRequest) => customersApi.create(data),
-    onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: [QUERY_KEYS.customerList] });
-      closeDialog();
-      toast.success('Customer created');
-    },
-    onError: (error: Error) => {
-      toast.error(`Failed to create customer: ${error.message}`);
-    },
-  });
-
-  const updateMutation = useMutation({
-    mutationFn: ({ id, data }: { id: string; data: UpdateCustomerRequest }) =>
-      customersApi.update(id, data),
-    onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: [QUERY_KEYS.customerList] });
-      closeDialog();
-      toast.success('Customer updated');
-    },
-    onError: (error: Error) => {
-      toast.error(`Failed to update customer: ${error.message}`);
-    },
-  });
-
-  const handleSubmit = () => {
-    if (!validateForm()) return;
+  // --- Mutations (domain hooks: invalidation + toasts live in the hooks) ---
+  const createMutation = useCreateCustomer();
+  const updateMutation = useUpdateCustomer();
 
+  const onSubmit = (values: CustomerFormValues) => {
     // Fix: WEB-M5 — the API contract is addresses: string[] (CustomerDtos.cs);
     // the old singular `address` field was silently dropped by model binding.
-    // The form edits the primary address; any additional addresses are preserved.
-    const payload = {
-      name: form.name.trim(),
-      addresses: [form.address.trim(), ...(editingCustomer?.addresses.slice(1) ?? [])],
-      ...(form.contactEmail.trim() ? { contactEmail: form.contactEmail.trim() } : {}),
-    };
+    // The form edits the primary address; any additional addresses are preserved
+    // (toCustomerRequest maps to addresses: [primary, ...rest]).
+    const payload = toCustomerRequest(values, editingCustomer?.addresses ?? []);
 
     if (isEditing) {
-      updateMutation.mutate({ id: editingCustomer.id, data: payload });
+      updateMutation.mutate(
+        { id: editingCustomer.id, data: payload },
+        { onSuccess: closeDialog }
+      );
     } else {
-      createMutation.mutate(payload);
+      createMutation.mutate(payload, { onSuccess: closeDialog });
     }
   };
 
@@ -324,54 +269,53 @@ export default function CustomerManagementPage() {
 
       {/* Create / Edit Dialog */}
       <Dialog open={dialogOpen} onClose={closeDialog} maxWidth="sm" fullWidth>
-        <DialogTitle>{isEditing ? 'Edit Customer' : 'New Customer'}</DialogTitle>
-        <DialogContent>
-          <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2, mt: 1 }}>
-            <TextField
-              label="Name"
-              value={form.name}
-              onChange={(e) => handleFieldChange('name', e.target.value)}
-              error={!!formErrors.name}
-              helperText={formErrors.name}
-              size="small"
-              required
-              fullWidth
-              autoFocus
-            />
-            <TextField
-              label="Address"
-              value={form.address}
-              onChange={(e) => handleFieldChange('address', e.target.value)}
-              error={!!formErrors.address}
-              helperText={formErrors.address}
-              size="small"
-              required
-              fullWidth
-            />
-            <TextField
-              label="Contact Email"
-              type="email"
-              value={form.contactEmail}
-              onChange={(e) => handleFieldChange('contactEmail', e.target.value)}
-              error={!!formErrors.contactEmail}
-              helperText={formErrors.contactEmail || 'Optional. Used for proposal PDF delivery.'}
-              size="small"
-              fullWidth
-            />
-          </Box>
-        </DialogContent>
-        <DialogActions>
-          <Button onClick={closeDialog} disabled={isSaving}>
-            Cancel
-          </Button>
-          <Button
-            variant="contained"
-            onClick={handleSubmit}
-            disabled={isSaving}
-          >
-            {isSaving ? (isEditing ? 'Saving...' : 'Creating...') : isEditing ? 'Save Changes' : 'Create Customer'}
-          </Button>
-        </DialogActions>
+        <form onSubmit={handleSubmit(onSubmit)} noValidate>
+          <DialogTitle>{isEditing ? 'Edit Customer' : 'New Customer'}</DialogTitle>
+          <DialogContent>
+            <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2, mt: 1 }}>
+              <TextField
+                label="Name"
+                {...register('name')}
+                error={!!errors.name}
+                helperText={errors.name?.message}
+                size="small"
+                required
+                fullWidth
+                autoFocus
+              />
+              <TextField
+                label="Address"
+                {...register('address')}
+                error={!!errors.address}
+                helperText={errors.address?.message}
+                size="small"
+                required
+                fullWidth
+              />
+              <TextField
+                label="Contact Email"
+                type="email"
+                {...register('contactEmail')}
+                error={!!errors.contactEmail}
+                helperText={errors.contactEmail?.message || 'Optional. Used for proposal PDF delivery.'}
+                size="small"
+                fullWidth
+              />
+            </Box>
+          </DialogContent>
+          <DialogActions>
+            <Button onClick={closeDialog} disabled={isSaving}>
+              Cancel
+            </Button>
+            <Button
+              type="submit"
+              variant="contained"
+              disabled={isSaving}
+            >
+              {isSaving ? (isEditing ? 'Saving...' : 'Creating...') : isEditing ? 'Save Changes' : 'Create Customer'}
+            </Button>
+          </DialogActions>
+        </form>
       </Dialog>
     </Box>
   );