refactor(frontend): useMutationWithToast + useModal hooks, migrate admin surfaces

- 92 mutations across 40 files moved to useMutationWithToast
  (success/error toast + invalidateKeys); complex flows left as-is
- 24 boolean modal flags moved to useModal
- Mutations without an original onError intentionally not migrated
  to avoid introducing new error toasts

frontend/src/components/admin/AdminGuestsList.tsx

@@ -1,5 +1,5 @@
 import React, { useState } from 'react';
-import { useQuery, useQueryClient, useMutation } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import { Trash2, Eye, Download, UserPlus, Grid3x3, List } from 'lucide-react';
 import { Card, Button, Loading } from '../common';
@@ -9,6 +9,7 @@ import { GuestSelectionsAggregate } from './GuestSelectionsAggregate';
 import { GuestInviteDialog } from './GuestInviteDialog';
 import { toast } from 'react-toastify';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 interface AdminGuestsListProps {
   eventId: number;
@@ -20,37 +21,34 @@ type View = 'list' | 'aggregate';
 export const AdminGuestsList: React.FC<AdminGuestsListProps> = ({ eventId, eventName }) => {
   const { t } = useTranslation();
   const { format: fmtDate } = useLocalizedDate();
-  const queryClient = useQueryClient();
   const [view, setView] = useState<View>('list');
   const [selectedGuest, setSelectedGuest] = useState<AdminGuest | null>(null);
   const [mergeMode, setMergeMode] = useState(false);
   const [mergeSelection, setMergeSelection] = useState<number[]>([]);
-  const [inviteDialogOpen, setInviteDialogOpen] = useState(false);
+  const inviteModal = useModal();
 
   const { data, isLoading, refetch } = useQuery({
     queryKey: ['admin-guests', eventId],
     queryFn: () => guestsService.getEventGuests(eventId),
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (guestId: number) => guestsService.deleteGuest(eventId, guestId),
-    onSuccess: () => {
+    successMessage: t('admin.guests.deletedToast', 'Guest removed'),
-      toast.success(t('admin.guests.deletedToast', 'Guest removed'));
+    invalidateKeys: [['admin-guests', eventId]],
-      queryClient.invalidateQueries({ queryKey: ['admin-guests', eventId] });
+    errorMessage: () => t('admin.guests.deletedError', 'Failed to remove guest'),
-    },
-    onError: () => toast.error(t('admin.guests.deletedError', 'Failed to remove guest')),
   });
 
-  const mergeMutation = useMutation({
+  const mergeMutation = useMutationWithToast({
     mutationFn: ({ keepId, mergeIds }: { keepId: number; mergeIds: number[] }) =>
       guestsService.mergeGuests(eventId, keepId, mergeIds),
+    successMessage: t('admin.guests.mergedToast', 'Guests merged'),
+    invalidateKeys: [['admin-guests', eventId]],
     onSuccess: () => {
-      toast.success(t('admin.guests.mergedToast', 'Guests merged'));
       setMergeMode(false);
       setMergeSelection([]);
-      queryClient.invalidateQueries({ queryKey: ['admin-guests', eventId] });
     },
-    onError: () => toast.error(t('admin.guests.mergedError', 'Failed to merge guests')),
+    errorMessage: () => t('admin.guests.mergedError', 'Failed to merge guests'),
   });
 
   const handleDelete = (guest: AdminGuest) => {
@@ -160,7 +158,7 @@ export const AdminGuestsList: React.FC<AdminGuestsListProps> = ({ eventId, event
                 variant="outline"
                 size="sm"
                 leftIcon={<UserPlus className="w-4 h-4" />}
-                onClick={() => setInviteDialogOpen(true)}
+                onClick={inviteModal.open}
               >
                 {t('admin.guests.createInvite', 'Create invite')}
               </Button>
@@ -331,12 +329,12 @@ export const AdminGuestsList: React.FC<AdminGuestsListProps> = ({ eventId, event
         />
       )}
 
-      {inviteDialogOpen && (
+      {inviteModal.isOpen && (
         <GuestInviteDialog
           eventId={eventId}
           eventName={eventName}
           onClose={() => {
-            setInviteDialogOpen(false);
+            inviteModal.close();
             refetch();
           }}
         />

frontend/src/components/admin/AdminHeader.tsx

@@ -9,6 +9,7 @@ import { useAdminAuth } from '../../contexts';
 import { useAdminDarkMode } from '../../contexts/AdminDarkModeContext';
 import { useOnClickOutside } from '../../hooks/useOnClickOutside';
 import { usePublicSettings } from '../../hooks/usePublicSettings';
+import { useModal } from '../../hooks';
 import { PasswordChangeModal } from './PasswordChangeModal';
 import { LanguageSelector, SUPPORTED_LANGUAGES } from '../common';
 import { notificationsService } from '../../services/notifications.service';
@@ -25,10 +26,10 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
   const { isDark, toggle: toggleDarkMode, forcedMode } = useAdminDarkMode();
   const { t, i18n } = useTranslation();
   const { format, formatDistanceToNow } = useLocalizedDate();
-  const [showUserMenu, setShowUserMenu] = useState(false);
+  const userMenuModal = useModal();
-  const [showUserMenuLangSection, setShowUserMenuLangSection] = useState(false);
+  const userMenuLangSectionModal = useModal();
-  const [showNotifications, setShowNotifications] = useState(false);
+  const notificationsModal = useModal();
-  const [showPasswordModal, setShowPasswordModal] = useState(false);
+  const passwordModal = useModal();
   const queryClient = useQueryClient();
 
   const { data: brandingSettings, isLoading: brandingLoading } = usePublicSettings();
@@ -138,8 +139,8 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
   // outer dropdown closes, so re-opening it doesn't surprise the user
   // with the language list already expanded from the previous session.
   const closeUserMenu = () => {
-    setShowUserMenu(false);
+    userMenuModal.close();
-    setShowUserMenuLangSection(false);
+    userMenuLangSectionModal.close();
   };
   const handleUserMenuLangSelect = (languageCode: string) => {
     i18n.changeLanguage(languageCode);
@@ -150,7 +151,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
   const notificationRef = useRef<HTMLDivElement>(null);
 
   useOnClickOutside(userMenuRef, closeUserMenu);
-  useOnClickOutside(notificationRef, () => setShowNotifications(false));
+  useOnClickOutside(notificationRef, notificationsModal.close);
 
   const handleLogout = () => {
     logout();
@@ -159,8 +160,8 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
 
   // Fetch notifications
   const { data: notificationsData } = useQuery({
-    queryKey: ['notifications', showNotifications],
+    queryKey: ['notifications', notificationsModal.isOpen],
-    queryFn: () => notificationsService.getNotifications(showNotifications, 20),
+    queryFn: () => notificationsService.getNotifications(notificationsModal.isOpen, 20),
     refetchInterval: 60000, // Refetch every minute
   });
 
@@ -297,7 +298,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
             {/* Notifications */}
             <div className="relative" ref={notificationRef}>
               <button
-                onClick={() => setShowNotifications(!showNotifications)}
+                onClick={notificationsModal.toggle}
                 className="relative p-2 text-neutral-500 dark:text-neutral-400 hover:text-neutral-700 dark:hover:text-neutral-200 hover:bg-neutral-100 dark:hover:bg-neutral-800 rounded-lg transition-colors"
               >
                 <Bell className="w-5 h-5" />
@@ -307,7 +308,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
               </button>
 
               {/* Notifications dropdown */}
-              {showNotifications && (
+              {notificationsModal.isOpen && (
                 <div className="absolute right-0 mt-2 w-96 bg-white dark:bg-neutral-800 rounded-lg shadow-lg border border-neutral-200 dark:border-neutral-700">
                   <div className="px-4 py-3 border-b border-neutral-100 dark:border-neutral-700 flex items-center justify-between">
                     <h3 className="text-sm font-semibold text-neutral-900 dark:text-neutral-100">{t('admin.notifications')}</h3>
@@ -368,7 +369,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
                   {notifications.length > 0 && (
                     <div className="px-4 py-2 border-t border-neutral-100 dark:border-neutral-700 text-center">
                       <button
-                        onClick={() => setShowNotifications(false)}
+                        onClick={notificationsModal.close}
                         className="text-sm text-accent hover:opacity-80"
                       >
                         {t('admin.close')}
@@ -382,7 +383,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
             {/* User menu */}
             <div className="relative" ref={userMenuRef}>
               <button
-                onClick={() => setShowUserMenu(!showUserMenu)}
+                onClick={userMenuModal.toggle}
                 className="flex items-center gap-3 p-2 hover:bg-neutral-100 dark:hover:bg-neutral-800 rounded-lg transition-colors"
               >
                 <div className="text-right hidden sm:block">
@@ -395,7 +396,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
               </button>
 
               {/* User dropdown */}
-              {showUserMenu && (
+              {userMenuModal.isOpen && (
                 <div className="absolute right-0 mt-2 w-56 bg-white dark:bg-neutral-800 rounded-lg shadow-lg border border-neutral-200 dark:border-neutral-700 py-1">
                   <div className="px-4 py-2 border-b border-neutral-100 dark:border-neutral-700 sm:hidden">
                     <p className="text-sm font-medium text-neutral-900 dark:text-neutral-100">{user?.username}</p>
@@ -408,16 +409,16 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
                       so the menu isn't 8 rows taller by default. */}
                   <div className="sm:hidden border-b border-neutral-100 dark:border-neutral-700">
                     <button
-                      onClick={() => setShowUserMenuLangSection(!showUserMenuLangSection)}
+                      onClick={userMenuLangSectionModal.toggle}
                       className="w-full px-4 py-2 text-left text-sm text-neutral-700 dark:text-neutral-300 hover:bg-neutral-50 dark:hover:bg-neutral-700 flex items-center gap-3"
-                      aria-expanded={showUserMenuLangSection}
+                      aria-expanded={userMenuLangSectionModal.isOpen}
                     >
                       <Globe className="w-4 h-4" />
                       <span className="flex-1">{t('common.language', 'Language')}</span>
                       <currentLanguage.Flag className="w-4 h-4" />
-                      <ChevronDown className={`w-4 h-4 transition-transform ${showUserMenuLangSection ? 'rotate-180' : ''}`} />
+                      <ChevronDown className={`w-4 h-4 transition-transform ${userMenuLangSectionModal.isOpen ? 'rotate-180' : ''}`} />
                     </button>
-                    {showUserMenuLangSection && (
+                    {userMenuLangSectionModal.isOpen && (
                       <div className="bg-neutral-50 dark:bg-neutral-900 py-1">
                         {SUPPORTED_LANGUAGES.map((language) => (
                           <button
@@ -449,7 +450,7 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
                   <button
                     onClick={() => {
                       closeUserMenu();
-                      setShowPasswordModal(true);
+                      passwordModal.open();
                     }}
                     className="w-full px-4 py-2 text-left text-sm text-neutral-700 dark:text-neutral-300 hover:bg-neutral-50 dark:hover:bg-neutral-700 flex items-center gap-3"
                   >
@@ -472,8 +473,8 @@ export const AdminHeader: React.FC<AdminHeaderProps> = ({ onMenuClick }) => {
       
       {/* Password Change Modal */}
       <PasswordChangeModal
-        isOpen={showPasswordModal} 
+        isOpen={passwordModal.isOpen}
-        onClose={() => setShowPasswordModal(false)} 
+        onClose={passwordModal.close}
       />
     </header>
   );

frontend/src/components/admin/AdminPhotoViewer.tsx

@@ -1,7 +1,7 @@
 import React, { useState } from 'react';
 import { X, ChevronLeft, ChevronRight, Download, Trash2, Tag, Calendar, HardDrive, Eye, MousePointer, MessageSquare, Star, Heart, CheckCircle, XCircle, AlertCircle } from 'lucide-react';
 import { toast } from 'react-toastify';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 
 import { AdminPhoto } from '../../services/photos.service';
 import { photosService } from '../../services/photos.service';
@@ -10,6 +10,7 @@ import { Button } from '../common';
 import { AdminAuthenticatedImage } from './AdminAuthenticatedImage';
 import { AdminAuthenticatedVideo } from './AdminAuthenticatedVideo';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 type AdminFeedbackResponse = {
   feedback: PhotoFeedback[];
@@ -35,8 +36,8 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
 }) => {
   const [currentIndex, setCurrentIndex] = useState(initialIndex);
   const [isDeleting, setIsDeleting] = useState(false);
-  const [showCategoryMenu, setShowCategoryMenu] = useState(false);
+  const categoryMenuModal = useModal();
-  const [expandedComments, setExpandedComments] = useState(false);
+  const commentsModal = useModal();
   const queryClient = useQueryClient();
   const { formatDateTime: fmtDateTime } = useLocalizedDate();
   
@@ -115,7 +116,7 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
     try {
       await photosService.updatePhotoCategory(eventId, currentPhoto.id, categoryId);
       toast.success('Category updated');
-      setShowCategoryMenu(false);
+      categoryMenuModal.close();
       // Invalidate photos query to refresh data
       await queryClient.invalidateQueries({ queryKey: ['admin-event-photos', eventId.toString()] });
       await queryClient.invalidateQueries({ queryKey: ['admin-event-photos', eventId] });
@@ -127,27 +128,19 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
   };
 
   // Mutations for feedback moderation
-  const moderateFeedbackMutation = useMutation({
+  const moderateFeedbackMutation = useMutationWithToast({
     mutationFn: ({ feedbackId, action }: { feedbackId: string; action: 'approve' | 'hide' | 'reject' }) =>
       feedbackService.moderateFeedback(feedbackId, action),
-    onSuccess: () => {
+    invalidateKeys: [['admin-photo-feedback', eventId, currentPhoto?.id]],
-      queryClient.invalidateQueries({ queryKey: ['admin-photo-feedback', eventId, currentPhoto?.id] });
+    successMessage: 'Feedback moderated successfully',
-      toast.success('Feedback moderated successfully');
+    errorMessage: () => 'Failed to moderate feedback'
-    },
-    onError: () => {
-      toast.error('Failed to moderate feedback');
-    }
   });
 
-  const deleteFeedbackMutation = useMutation({
+  const deleteFeedbackMutation = useMutationWithToast({
     mutationFn: (feedbackId: string) => feedbackService.deleteFeedback(feedbackId),
-    onSuccess: () => {
+    invalidateKeys: [['admin-photo-feedback', eventId, currentPhoto?.id]],
-      queryClient.invalidateQueries({ queryKey: ['admin-photo-feedback', eventId, currentPhoto?.id] });
+    successMessage: 'Feedback deleted successfully',
-      toast.success('Feedback deleted successfully');
+    errorMessage: () => 'Failed to delete feedback'
-    },
-    onError: () => {
-      toast.error('Failed to delete feedback');
-    }
   });
 
   React.useEffect(() => {
@@ -266,7 +259,7 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
                 Category
               </span>
               <button
-                onClick={() => setShowCategoryMenu(!showCategoryMenu)}
+                onClick={categoryMenuModal.toggle}
                 className="text-xs text-accent hover:text-accent-dark"
               >
                 Change
@@ -276,7 +269,7 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
               {currentPhoto.category_name || 'Uncategorized'}
             </p>
             
-            {showCategoryMenu && (
+            {categoryMenuModal.isOpen && (
               <div className="mt-2 bg-neutral-800 rounded-lg p-2">
                 <button
                   onClick={() => handleCategoryChange(null)}
@@ -393,13 +386,13 @@ export const AdminPhotoViewer: React.FC<AdminPhotoViewerProps> = ({
               {comments.length > 0 && (
                 <div className="space-y-2">
                   <button
-                    onClick={() => setExpandedComments(!expandedComments)}
+                    onClick={commentsModal.toggle}
                     className="text-xs text-accent hover:text-accent-dark mb-2"
                   >
-                    {expandedComments ? 'Hide' : 'Show'} Comments ({comments.length})
+                    {commentsModal.isOpen ? 'Hide' : 'Show'} Comments ({comments.length})
                   </button>
 
-                  {expandedComments && (
+                  {commentsModal.isOpen && (
                     <div className="space-y-3 max-h-64 overflow-y-auto">
                       {comments.map((comment) => (
                           <div key={comment.id} className="bg-neutral-800 rounded-lg p-3">

frontend/src/components/admin/BackupHistory.jsx

@@ -20,10 +20,10 @@ import {
   RefreshCw,
   Loader2
 } from 'lucide-react';
-import { toast } from 'react-toastify';
+import { useQuery } from '@tanstack/react-query';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { Button, Card, Input, Loading } from '../common';
 import { api } from '../../config/api';
+import { useMutationWithToast } from '../../hooks';
 // Per [[feedback_respect_general_format_settings]]: route every displayed
 // date/time through useLocalizedDate so the admin's general_date_format +
 // general_time_format settings apply uniformly. Previously the backup
@@ -53,7 +53,6 @@ export const BackupHistory = () => {
   const [searchTerm, setSearchTerm] = useState('');
   const [filterStatus, setFilterStatus] = useState('all');
   const [currentPage, setCurrentPage] = useState(1);
-  const queryClient = useQueryClient();
   // Locale-aware formatters that respect admin's general_date_format +
   // general_time_format settings. See useLocalizedDate.ts for the full
   // contract; formatTime gives "HH:mm" (24h) or "h:mm a" (12h) based on
@@ -77,18 +76,14 @@ export const BackupHistory = () => {
   });
 
   // Delete backup mutation
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: async (backupId) => {
       const response = await api.delete(`/admin/backup/runs/${backupId}`);
       return response.data;
     },
-    onSuccess: () => {
+    successMessage: 'Backup deleted successfully',
-      toast.success('Backup deleted successfully');
+    invalidateKeys: [['backup-history']],
-      queryClient.invalidateQueries({ queryKey: ['backup-history'] });
+    errorMessage: 'Failed to delete backup'
-    },
-    onError: (error) => {
-      toast.error(error.response?.data?.error || 'Failed to delete backup');
-    }
   });
 
   const toggleRowExpansion = (id) => {

frontend/src/components/admin/CategoryManager.tsx

@@ -1,15 +1,14 @@
 import React, { useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { Plus, Edit2, Trash2, Loader2 } from 'lucide-react';
-import { toast } from 'react-toastify';
 import { useTranslation } from 'react-i18next';
 import { categoriesService, type PhotoCategory } from '../../services/categories.service';
 import { Button } from '../common';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 export const CategoryManager: React.FC = () => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
+  const addingModal = useModal();
-  const [isAdding, setIsAdding] = useState(false);
   const [editingId, setEditingId] = useState<number | null>(null);
   const [newCategoryName, setNewCategoryName] = useState('');
   const [editingName, setEditingName] = useState('');
@@ -21,45 +20,37 @@ export const CategoryManager: React.FC = () => {
   });
 
   // Create category mutation
-  const createMutation = useMutation({
+  const createMutation = useMutationWithToast({
     mutationFn: (name: string) =>
       categoriesService.createCategory({ name, is_global: true }),
+    invalidateKeys: [['global-categories']],
+    successMessage: t('categories.categoryCreatedSuccess'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['global-categories'] });
-      toast.success(t('categories.categoryCreatedSuccess'));
       setNewCategoryName('');
-      setIsAdding(false);
+      addingModal.close();
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToCreateCategory'));
     },
+    errorMessage: t('categories.failedToCreateCategory'),
   });
 
   // Update category mutation
-  const updateMutation = useMutation({
+  const updateMutation = useMutationWithToast({
     mutationFn: ({ id, name }: { id: number; name: string }) =>
       categoriesService.updateCategory(id, name),
+    invalidateKeys: [['global-categories']],
+    successMessage: t('toast.categoryUpdated'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['global-categories'] });
-      toast.success(t('toast.categoryUpdated'));
       setEditingId(null);
       setEditingName('');
     },
-    onError: (error: any) => {
+    errorMessage: t('toast.saveError'),
-      toast.error(error.response?.data?.error || t('toast.saveError'));
-    },
   });
 
   // Delete category mutation
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: categoriesService.deleteCategory,
-    onSuccess: () => {
+    invalidateKeys: [['global-categories']],
-      queryClient.invalidateQueries({ queryKey: ['global-categories'] });
+    successMessage: t('categories.categoryDeletedSuccess'),
-      toast.success(t('categories.categoryDeletedSuccess'));
+    errorMessage: t('categories.failedToDeleteCategory'),
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToDeleteCategory'));
-    },
   });
 
   const handleCreate = () => {
@@ -102,11 +93,11 @@ export const CategoryManager: React.FC = () => {
     <div className="space-y-4">
       <div className="flex justify-between items-center">
         <h3 className="text-lg font-semibold text-neutral-900 dark:text-neutral-100">{t('categories.title')}</h3>
-        {!isAdding && (
+        {!addingModal.isOpen && (
           <Button
             variant="primary"
             size="sm"
-            onClick={() => setIsAdding(true)}
+            onClick={addingModal.open}
             leftIcon={<Plus className="w-4 h-4" />}
           >
             {t('categories.addCategory')}
@@ -115,7 +106,7 @@ export const CategoryManager: React.FC = () => {
       </div>
 
       {/* Add new category form */}
-      {isAdding && (
+      {addingModal.isOpen && (
         <div className="flex gap-2 p-3 bg-neutral-50 dark:bg-neutral-800 rounded-lg">
           <input
             type="text"
@@ -142,7 +133,7 @@ export const CategoryManager: React.FC = () => {
             variant="secondary"
             size="sm"
             onClick={() => {
-              setIsAdding(false);
+              addingModal.close();
               setNewCategoryName('');
             }}
           >

frontend/src/components/admin/ChartOfAccountsManager.tsx

@@ -13,15 +13,15 @@
  * VatCodesManager. Scoping each patch keeps the two from reverting each other.
  */
 import React, { useEffect, useMemo, useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
-import { toast } from 'react-toastify';
 import { X, Plus, Pencil, Trash2, AlertCircle } from 'lucide-react';
 import { Button, Card, CardContent, Input, Loading } from '../common';
 import {
   ledgerService, type LedgerAccount, type AccountType, type LedgerSettings,
 } from '../../services/ledger.service';
 import { categoryLabel } from '../../services/accounting.service';
+import { useMutationWithToast } from '../../hooks';
 
 const ACCOUNT_TYPES: AccountType[] = ['asset', 'liability', 'equity', 'revenue', 'expense'];
 const labelCls = 'block text-xs font-medium text-neutral-700 dark:text-neutral-300 mb-1';
@@ -39,10 +39,11 @@ const AccountModal: React.FC<{ account?: LedgerAccount; onClose: () => void; onD
   const [number, setNumber] = useState(account?.number ?? '');
   const [name, setName] = useState(account?.name ?? '');
   const [type, setType] = useState<AccountType>(account?.type ?? 'expense');
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => isEdit ? ledgerService.updateAccount(account!.id, { number, name, type }) : ledgerService.createAccount({ number, name, type }),
-    onSuccess: () => { toast.success(t('common.saved', 'Saved.')); onDone(); },
+    successMessage: t('common.saved', 'Saved.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    onSuccess: () => onDone(),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
   return (
     <div className="fixed inset-0 z-50 flex items-start justify-center bg-black/50 p-4">
@@ -85,27 +86,29 @@ export const ChartOfAccountsManager: React.FC = () => {
 
   const refetchAll = () => { qc.invalidateQueries({ queryKey: ['ledger-accounts'] }); qc.invalidateQueries({ queryKey: ['ledger-vat-codes'] }); qc.invalidateQueries({ queryKey: ['ledger-mappings'] }); };
 
-  const delAccount = useMutation({
+  const delAccount = useMutationWithToast({
     mutationFn: (id: number) => ledgerService.deleteAccount(id),
-    onSuccess: () => { toast.success(t('common.deleted', 'Deleted.')); refetchAll(); },
+    successMessage: t('common.deleted', 'Deleted.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    onSuccess: () => refetchAll(),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
-  const setCat = useMutation({
+  const setCat = useMutationWithToast({
     mutationFn: ({ id, accId }: { id: number; accId: number | null }) => ledgerService.setCategoryAccount(id, accId),
-    onSuccess: () => { qc.invalidateQueries({ queryKey: ['ledger-mappings'] }); },
+    invalidateKeys: [['ledger-mappings']],
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
   // Save ONLY the account keys — the VAT maps are owned by VatCodesManager and
   // updateSettings is a partial merge, so scoping the patch here prevents a
   // stale full-settings save from reverting the maps.
-  const saveSettings = useMutation({
+  const saveSettings = useMutationWithToast({
     mutationFn: () => {
       const patch: Partial<LedgerSettings> = {};
       for (const k of SETTING_ACCOUNT_KEYS) patch[k] = settings[k];
       return ledgerService.updateSettings(patch);
     },
-    onSuccess: () => { toast.success(t('ledger.settingsSaved', 'Mappings saved.')); qc.invalidateQueries({ queryKey: ['ledger-mappings'] }); },
+    successMessage: t('ledger.settingsSaved', 'Mappings saved.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    invalidateKeys: [['ledger-mappings']],
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
 
   const setAcctSetting = (key: keyof LedgerSettings, value: string) => setSettings((s) => ({ ...s, [key]: value }));

frontend/src/components/admin/CssTemplateEditor.tsx

@@ -6,6 +6,7 @@ import { Save, RotateCcw, Code, AlertTriangle, Check } from 'lucide-react';
 import { Button, Card, Loading } from '../common';
 import { cssTemplatesService, CssTemplate } from '../../services/cssTemplates.service';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 
 export const CssTemplateEditor: React.FC = () => {
   const { t } = useTranslation();
@@ -57,15 +58,11 @@ export const CssTemplateEditor: React.FC = () => {
   });
 
   // Reset mutation
-  const resetMutation = useMutation({
+  const resetMutation = useMutationWithToast({
     mutationFn: () => cssTemplatesService.resetToDefault(),
-    onSuccess: () => {
+    invalidateKeys: [['css-templates']],
-      queryClient.invalidateQueries({ queryKey: ['css-templates'] });
+    successMessage: t('cssTemplates.reset', 'Template reset to default'),
-      toast.success(t('cssTemplates.reset', 'Template reset to default'));
+    errorMessage: (error: Error) => error.message || t('cssTemplates.resetFailed', 'Failed to reset template')
-    },
-    onError: (error: Error) => {
-      toast.error(error.message || t('cssTemplates.resetFailed', 'Failed to reset template'));
-    }
   });
 
   const activeTemplate = localTemplates.find(t => t.slot_number === activeSlot);

frontend/src/components/admin/CustomerDashboardBrandingCard.tsx

@@ -14,11 +14,11 @@
  */
 import React, { useEffect, useState } from 'react';
 import { useTranslation } from 'react-i18next';
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { Save, Image as ImageIcon, Type, UserCog } from 'lucide-react';
 import { Button, Card, Loading } from '../common';
 import { api } from '../../config/api';
+import { useMutationWithToast } from '../../hooks';
 
 interface CustomerSurfaceSettings {
   customer_show_logo: boolean;
@@ -74,7 +74,6 @@ const Toggle: React.FC<ToggleProps> = ({ enabled, onChange, label, hint, icon: I
 
 export const CustomerDashboardBrandingCard: React.FC = () => {
   const { t } = useTranslation();
-  const qc = useQueryClient();
 
   const { data, isLoading } = useQuery({
     queryKey: ['admin-settings-customer-surface'],
@@ -87,17 +86,14 @@ export const CustomerDashboardBrandingCard: React.FC = () => {
   const [form, setForm] = useState<CustomerSurfaceSettings>(DEFAULTS);
   useEffect(() => { if (data) setForm(data); }, [data]);
 
-  const saveMutation = useMutation({
+  const saveMutation = useMutationWithToast({
     mutationFn: () => api.put('/admin/settings/customer-surface', form),
-    onSuccess: () => {
-      qc.invalidateQueries({ queryKey: ['admin-settings-customer-surface'] });
     // The customer-side session response (/api/customer/auth/session)
-      // also bundles these as branding flags — invalidate so a customer
+    // also bundles these as branding flags — invalidate public-settings so
-      // tab refresh picks up the new visibility on the next focus.
+    // a customer tab refresh picks up the new visibility on the next focus.
-      qc.invalidateQueries({ queryKey: ['public-settings'] });
+    invalidateKeys: [['admin-settings-customer-surface'], ['public-settings']],
-      toast.success(t('settings.customerSurface.saved', 'Customer dashboard branding saved'));
+    successMessage: t('settings.customerSurface.saved', 'Customer dashboard branding saved'),
-    },
+    errorMessage: () => t('settings.customerSurface.error', 'Could not save settings'),
-    onError: () => toast.error(t('settings.customerSurface.error', 'Could not save settings')),
   });
 
   const toggle = (key: keyof CustomerSurfaceSettings) => {

frontend/src/components/admin/EventCategoryManager.tsx

@@ -1,20 +1,19 @@
 import React, { useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { Plus, X, Loader2, Image as ImageIcon, Check, Download, DownloadCloud } from 'lucide-react';
-import { toast } from 'react-toastify';
 import { categoriesService, type PhotoCategory } from '../../services/categories.service';
 import { photosService } from '../../services/photos.service';
 import { Button, Card, AuthenticatedImage } from '../common';
 import { useTranslation } from 'react-i18next';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 interface EventCategoryManagerProps {
   eventId: number;
 }
 
 export const EventCategoryManager: React.FC<EventCategoryManagerProps> = ({ eventId }) => {
-  const queryClient = useQueryClient();
   const { t } = useTranslation();
-  const [isAdding, setIsAdding] = useState(false);
+  const addingModal = useModal();
   const [newCategoryName, setNewCategoryName] = useState('');
   const [heroPickerCategoryId, setHeroPickerCategoryId] = useState<number | null>(null);
 
@@ -35,67 +34,55 @@ export const EventCategoryManager: React.FC<EventCategoryManagerProps> = ({ even
   const eventCategories = categories.filter(cat => !cat.is_global);
 
   // Create category mutation
-  const createMutation = useMutation({
+  const createMutation = useMutationWithToast({
     mutationFn: (name: string) =>
       categoriesService.createCategory({
         name,
         is_global: false,
         event_id: eventId
       }),
+    invalidateKeys: [['event-categories', eventId]],
+    successMessage: t('categories.categoryCreatedSuccess'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['event-categories', eventId] });
-      toast.success(t('categories.categoryCreatedSuccess'));
       setNewCategoryName('');
-      setIsAdding(false);
+      addingModal.close();
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToCreateCategory'));
     },
+    errorMessage: t('categories.failedToCreateCategory'),
   });
 
   // Delete category mutation
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: categoriesService.deleteCategory,
-    onSuccess: () => {
+    invalidateKeys: [['event-categories', eventId]],
-      queryClient.invalidateQueries({ queryKey: ['event-categories', eventId] });
+    successMessage: t('categories.categoryDeletedSuccess'),
-      toast.success(t('categories.categoryDeletedSuccess'));
+    errorMessage: t('categories.failedToDeleteCategory'),
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToDeleteCategory'));
-    },
   });
 
   // Set hero photo mutation
-  const heroMutation = useMutation({
+  const heroMutation = useMutationWithToast({
     mutationFn: ({ categoryId, photoId }: { categoryId: number; photoId: number | null }) =>
       categoriesService.setCategoryHeroPhoto(categoryId, photoId),
-    onSuccess: (_data, variables) => {
+    invalidateKeys: [['event-categories', eventId]],
-      queryClient.invalidateQueries({ queryKey: ['event-categories', eventId] });
+    successMessage: (_data, variables) =>
+      variables.photoId ? t('categories.coverPhotoSet') : t('categories.coverPhotoRemoved'),
+    onSuccess: () => {
       setHeroPickerCategoryId(null);
-      toast.success(variables.photoId ? t('categories.coverPhotoSet') : t('categories.coverPhotoRemoved'));
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToSetCoverPhoto'));
     },
+    errorMessage: t('categories.failedToSetCoverPhoto'),
   });
 
   // Toggle per-category download permission (#640). The backend AND's this
   // with the event-level `allow_downloads`, so disabling at either level
   // blocks downloads for this category's photos.
-  const downloadToggleMutation = useMutation({
+  const downloadToggleMutation = useMutationWithToast({
     mutationFn: ({ category, allow }: { category: PhotoCategory; allow: boolean }) =>
       categoriesService.updateCategory(category.id, category.name, { allow_downloads: allow }),
-    onSuccess: (_data, variables) => {
+    invalidateKeys: [['event-categories', eventId]],
-      queryClient.invalidateQueries({ queryKey: ['event-categories', eventId] });
+    successMessage: (_data, variables) =>
-      toast.success(
       variables.allow
         ? t('categories.downloadsEnabled', 'Downloads enabled for this category')
-          : t('categories.downloadsDisabled', 'Downloads disabled for this category')
+        : t('categories.downloadsDisabled', 'Downloads disabled for this category'),
-      );
+    errorMessage: t('categories.failedToToggleDownloads', 'Failed to update download permission'),
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('categories.failedToToggleDownloads', 'Failed to update download permission'));
-    },
   });
 
   const handleCreate = () => {
@@ -130,11 +117,11 @@ export const EventCategoryManager: React.FC<EventCategoryManagerProps> = ({ even
     <div className="space-y-3">
       <div className="flex justify-between items-center">
         <h3 className="text-sm font-medium text-neutral-700 dark:text-neutral-300">{t('categories.eventSpecificCategories')}</h3>
-        {!isAdding && (
+        {!addingModal.isOpen && (
           <Button
             variant="outline"
             size="sm"
-            onClick={() => setIsAdding(true)}
+            onClick={addingModal.open}
             leftIcon={<Plus className="w-3 h-3" />}
           >
             {t('common.add')}
@@ -148,7 +135,7 @@ export const EventCategoryManager: React.FC<EventCategoryManagerProps> = ({ even
       </p>
 
       {/* Add new category form */}
-      {isAdding && (
+      {addingModal.isOpen && (
         <div className="flex gap-2">
           <input
             type="text"
@@ -175,7 +162,7 @@ export const EventCategoryManager: React.FC<EventCategoryManagerProps> = ({ even
             variant="outline"
             size="sm"
             onClick={() => {
-              setIsAdding(false);
+              addingModal.close();
               setNewCategoryName('');
             }}
           >

frontend/src/components/admin/EventReminderOverrideCard.tsx

@@ -25,11 +25,10 @@
 
 import React, { useEffect, useState } from 'react';
 import { useTranslation } from 'react-i18next';
-import { useMutation, useQueryClient } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { Bell, BellOff, Save } from 'lucide-react';
 import { Button, Card, Input } from '../common';
 import { api } from '../../config/api';
+import { useMutationWithToast } from '../../hooks';
 
 export interface EventReminderOverrideCardProps {
   eventId: number;
@@ -48,7 +47,6 @@ export const EventReminderOverrideCard: React.FC<EventReminderOverrideCardProps>
   eventId, initial, onSaved,
 }) => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
 
   const [disabled, setDisabled] = useState<boolean>(!!initial.event_reminder_disabled);
   const [offsetDays, setOffsetDays] = useState<string>(
@@ -64,7 +62,7 @@ export const EventReminderOverrideCard: React.FC<EventReminderOverrideCardProps>
     setBodyOverride(initial.event_reminder_body_override || '');
   }, [initial.event_reminder_disabled, initial.event_reminder_offset_days, initial.event_reminder_body_override]);
 
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: async () => {
       const payload: Record<string, unknown> = {
         event_reminder_disabled: disabled,
@@ -83,18 +81,17 @@ export const EventReminderOverrideCard: React.FC<EventReminderOverrideCardProps>
       payload.event_reminder_body_override = bodyOverride.trim() === '' ? null : bodyOverride;
       await api.put(`/admin/events/${eventId}`, payload);
     },
+    successMessage: t('eventReminderOverride.saved', 'Reminder override saved.'),
+    invalidateKeys: [['admin-event', eventId], ['adminEvent', eventId]],
     onSuccess: () => {
-      toast.success(t('eventReminderOverride.saved', 'Reminder override saved.'));
-      queryClient.invalidateQueries({ queryKey: ['admin-event', eventId] });
-      queryClient.invalidateQueries({ queryKey: ['adminEvent', eventId] });
       onSaved?.();
     },
-    onError: (err: unknown) => {
+    errorMessage: (err: unknown) => {
       const e = err as { message?: string; response?: { data?: { error?: string } } };
-      toast.error(
+      return (
         e?.response?.data?.error
         || e?.message
-        || t('eventReminderOverride.saveError', 'Could not save reminder override.'),
+        || t('eventReminderOverride.saveError', 'Could not save reminder override.')
       );
     },
   });

frontend/src/components/admin/FeedbackModerationPanel.tsx

@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import {
@@ -8,12 +8,12 @@ import {
   CheckCircle,
   User
 } from 'lucide-react';
-import { toast } from 'react-toastify';
-
 import { Card, Loading, Button } from '../common';
 import { AdminAuthenticatedImage } from './AdminAuthenticatedImage';
 import { feedbackService, type FeedbackResponse, type PhotoFeedback } from '../../services/feedback.service';
+import { toast } from 'react-toastify';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useModal } from '../../hooks';
 
 interface FeedbackModerationPanelProps {
   eventId: number;
@@ -31,7 +31,7 @@ export const FeedbackModerationPanel: React.FC<FeedbackModerationPanelProps> = (
   const { t } = useTranslation();
   const { formatDateTime } = useLocalizedDate();
   const queryClient = useQueryClient();
-  const [showAll, setShowAll] = useState(false);
+  const showAllModal = useModal();
 
   // Fetch pending feedback
   const { data: feedbackData, isLoading } = useQuery<FeedbackResponse>({
@@ -39,7 +39,7 @@ export const FeedbackModerationPanel: React.FC<FeedbackModerationPanelProps> = (
     queryFn: () => feedbackService.getEventFeedback(eventId.toString(), {
       type: 'comment',
       status: 'pending',
-      limit: showAll ? 100 : maxItems
+      limit: showAllModal.isOpen ? 100 : maxItems
     }),
     refetchInterval: 30000 // Refresh every 30 seconds
   });
@@ -97,7 +97,7 @@ export const FeedbackModerationPanel: React.FC<FeedbackModerationPanelProps> = (
           </div>
         ) : (
           <div className="space-y-3">
-            {pendingComments.slice(0, showAll ? undefined : maxItems).map((item) => (
+            {pendingComments.slice(0, showAllModal.isOpen ? undefined : maxItems).map((item) => (
               <div key={item.id} className="border border-neutral-200 dark:border-neutral-700 rounded-lg p-4 hover:bg-neutral-50 dark:hover:bg-neutral-800">
                 <div className="flex items-start gap-3">
                   <div className="flex-shrink-0">
@@ -182,9 +182,9 @@ export const FeedbackModerationPanel: React.FC<FeedbackModerationPanelProps> = (
               </div>
             ))}
 
-            {pendingComments.length > maxItems && !showAll && (
+            {pendingComments.length > maxItems && !showAllModal.isOpen && (
               <button
-                onClick={() => setShowAll(true)}
+                onClick={showAllModal.open}
                 className="w-full text-center py-2 text-sm text-accent hover:opacity-80 font-medium"
               >
                 {t('feedback.showAll', 'Show all {{count}} pending comments', { count: pendingComments.length })}

frontend/src/components/admin/GuestInviteDialog.tsx

@@ -1,10 +1,10 @@
 import React, { useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { X, Copy, Check, Trash2 } from 'lucide-react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { Button, Input, Loading } from '../common';
 import { guestsService, GuestInvite } from '../../services/guests.service';
-import { toast } from 'react-toastify';
+import { useMutationWithToast } from '../../hooks';
 
 interface GuestInviteDialogProps {
   eventId: number;
@@ -19,7 +19,6 @@ interface GuestInviteDialogProps {
  */
 export const GuestInviteDialog: React.FC<GuestInviteDialogProps> = ({ eventId, onClose }) => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
   const [name, setName] = useState('');
   const [email, setEmail] = useState('');
   const [copiedId, setCopiedId] = useState<number | null>(null);
@@ -29,25 +28,22 @@ export const GuestInviteDialog: React.FC<GuestInviteDialogProps> = ({ eventId, o
     queryFn: () => guestsService.listInvites(eventId),
   });
 
-  const createMutation = useMutation({
+  const createMutation = useMutationWithToast({
     mutationFn: () => guestsService.createInvite(eventId, { name, email: email || undefined }),
+    successMessage: t('admin.guests.inviteCreated', 'Invite created'),
+    invalidateKeys: [['admin-guest-invites', eventId], ['admin-guests', eventId]],
     onSuccess: () => {
       setName('');
       setEmail('');
-      toast.success(t('admin.guests.inviteCreated', 'Invite created'));
-      queryClient.invalidateQueries({ queryKey: ['admin-guest-invites', eventId] });
-      queryClient.invalidateQueries({ queryKey: ['admin-guests', eventId] });
     },
-    onError: () => toast.error(t('admin.guests.inviteCreateError', 'Failed to create invite')),
+    errorMessage: () => t('admin.guests.inviteCreateError', 'Failed to create invite'),
   });
 
-  const revokeMutation = useMutation({
+  const revokeMutation = useMutationWithToast({
     mutationFn: (inviteId: number) => guestsService.revokeInvite(eventId, inviteId),
-    onSuccess: () => {
+    successMessage: t('admin.guests.inviteRevoked', 'Invite revoked'),
-      toast.success(t('admin.guests.inviteRevoked', 'Invite revoked'));
+    invalidateKeys: [['admin-guest-invites', eventId]],
-      queryClient.invalidateQueries({ queryKey: ['admin-guest-invites', eventId] });
+    errorMessage: () => t('admin.guests.inviteRevokeError', 'Failed to revoke invite'),
-    },
-    onError: () => toast.error(t('admin.guests.inviteRevokeError', 'Failed to revoke invite')),
   });
 
   const copy = (invite: GuestInvite) => {

frontend/src/components/admin/HoursSection.tsx

@@ -24,6 +24,7 @@ import { parseLocaleDecimal, parseDuration } from '../../utils/parsers';
 import { customerAdminService } from '../../services/customerAdmin.service';
 import { businessProfileService } from '../../services/businessProfile.service';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 import { ProjectSelect } from './ProjectSelect';
 
 export interface HoursSectionProps {
@@ -151,16 +152,11 @@ export const HoursSection: React.FC<HoursSectionProps> = ({
     },
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (entryId: number) => customerAdminService.deleteHourEntry(customerId, entryId),
-    onSuccess: () => {
+    invalidateKeys: [['admin-customer-hour-entries', customerId], ['admin-customer', customerId]],
-      qc.invalidateQueries({ queryKey: ['admin-customer-hour-entries', customerId] });
+    successMessage: t('customers.hours.toast.deleted', 'Entry deleted'),
-      qc.invalidateQueries({ queryKey: ['admin-customer', customerId] });
+    errorMessage: 'Failed to delete entry',
-      toast.success(t('customers.hours.toast.deleted', 'Entry deleted'));
-    },
-    onError: (err: any) => {
-      toast.error(err?.response?.data?.error || 'Failed to delete entry');
-    },
   });
 
   const billMutation = useMutation({

frontend/src/components/admin/IncomingMailConfigCard.tsx

@@ -14,6 +14,7 @@ import { toast } from 'react-toastify';
 import { Save, Server, User, Lock, Eye, EyeOff, FolderSearch, PlugZap, Mailbox, RefreshCw } from 'lucide-react';
 import { Button, Card, Input, Loading } from '../common';
 import { emailService, type IncomingMailConfig, type ImapFolder } from '../../services/email.service';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 const labelCls = 'block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-1';
 const selectCls = 'w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 rounded-lg focus:ring-2 focus:ring-primary-500 focus:border-accent-dark';
@@ -23,14 +24,14 @@ export const IncomingMailConfigCard: React.FC = () => {
   const qc = useQueryClient();
   const { data, isLoading } = useQuery({ queryKey: ['incoming-mail-config'], queryFn: () => emailService.getIncomingConfig() });
   const [cfg, setCfg] = useState<IncomingMailConfig>({ imap_host: '', imap_port: 993, imap_secure: true, imap_user: '', imap_pass: '', imap_folder: 'INBOX' });
-  const [showPassword, setShowPassword] = useState(false);
+  const passwordVisibilityModal = useModal();
   const [folders, setFolders] = useState<ImapFolder[] | null>(null);
 
   useEffect(() => { if (data) setCfg(data); }, [data]);
 
   const set = (k: keyof IncomingMailConfig, v: any) => setCfg((c) => ({ ...c, [k]: v }));
 
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => {
       // Mirror the SMTP card's client-side required guard. Host + port +
       // username are needed for the poller to authenticate (getImapConfig
@@ -40,20 +41,21 @@ export const IncomingMailConfigCard: React.FC = () => {
       }
       return emailService.updateIncomingConfig(cfg);
     },
-    onSuccess: () => { toast.success(t('email.incoming.savedToast', 'Incoming mail settings saved.')); qc.invalidateQueries({ queryKey: ['incoming-mail-config'] }); },
+    successMessage: t('email.incoming.savedToast', 'Incoming mail settings saved.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e?.response?.data?.errors?.[0]?.msg || e.message || 'Failed'),
+    invalidateKeys: [['incoming-mail-config']],
+    errorMessage: (e: any) => e?.response?.data?.error || e?.response?.data?.errors?.[0]?.msg || e.message || 'Failed',
   });
 
-  const test = useMutation({
+  const test = useMutationWithToast({
     mutationFn: () => emailService.testIncoming(cfg),
-    onSuccess: (r) => toast.success(t('email.incoming.testOk', 'Connected to {{folder}} — {{messages}} messages, {{unseen}} unread.', { folder: r.folder, messages: r.messages, unseen: r.unseen })),
+    successMessage: (r) => t('email.incoming.testOk', 'Connected to {{folder}} — {{messages}} messages, {{unseen}} unread.', { folder: r.folder, messages: r.messages, unseen: r.unseen }),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || t('email.incoming.testFailed', 'Connection failed.')),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || t('email.incoming.testFailed', 'Connection failed.'),
   });
 
-  const roundTrip = useMutation({
+  const roundTrip = useMutationWithToast({
     mutationFn: () => emailService.roundTripIncoming(),
-    onSuccess: (r) => toast.success(t('email.incoming.roundTripOk', 'Round-trip OK — delivered to {{recipient}} in {{seconds}}s.', { recipient: r.recipient, seconds: r.seconds })),
+    successMessage: (r) => t('email.incoming.roundTripOk', 'Round-trip OK — delivered to {{recipient}} in {{seconds}}s.', { recipient: r.recipient, seconds: r.seconds }),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || t('email.incoming.roundTripFailed', 'Round-trip test failed.')),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || t('email.incoming.roundTripFailed', 'Round-trip test failed.'),
   });
 
   const poll = useMutation({
@@ -143,15 +145,15 @@ export const IncomingMailConfigCard: React.FC = () => {
           <label className={labelCls}>{t('email.incoming.pass', 'Password')}</label>
           <div className="relative">
             <Input
-              type={showPassword ? 'text' : 'password'}
+              type={passwordVisibilityModal.isOpen ? 'text' : 'password'}
               value={cfg.imap_pass}
               onChange={(e) => set('imap_pass', e.target.value)}
               autoComplete="new-password"
               placeholder={t('email.enterPassword', 'Enter password')}
               leftIcon={<Lock className="w-5 h-5 text-neutral-400" />}
             />
-            <button type="button" onClick={() => setShowPassword(!showPassword)} className="absolute right-3 top-3 text-neutral-400 hover:text-neutral-600">
+            <button type="button" onClick={passwordVisibilityModal.toggle} className="absolute right-3 top-3 text-neutral-400 hover:text-neutral-600">
-              {showPassword ? <EyeOff className="w-5 h-5" /> : <Eye className="w-5 h-5" />}
+              {passwordVisibilityModal.isOpen ? <EyeOff className="w-5 h-5" /> : <Eye className="w-5 h-5" />}
             </button>
           </div>
         </div>

frontend/src/components/admin/PhotoExportMenu.tsx

@@ -5,6 +5,7 @@ import { useMutation } from '@tanstack/react-query';
 import { toast } from 'react-toastify';
 import { photosService, ExportOptions, FeedbackFilters } from '../../services/photos.service';
 import { ExportPreviewModal } from './ExportPreviewModal';
+import { useMutationWithToast, useModal } from '../../hooks';
 
 // TXT + CSV render through the preview modal (with copy-to-clipboard and a
 // fallback download button). XMP is a ZIP archive — no textarea preview makes
@@ -53,22 +54,20 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
   disabled = false
 }) => {
   const { t } = useTranslation();
-  const [isOpen, setIsOpen] = useState(false);
+  const menuModal = useModal();
   const [preview, setPreview] = useState<{
     format: 'txt' | 'csv';
     content: string;
     filename: string;
   } | null>(null);
 
-  const exportMutation = useMutation({
+  const exportMutation = useMutationWithToast({
     mutationFn: (options: ExportOptions) => photosService.exportPhotos(eventId, options),
+    successMessage: t('export.success', 'Export downloaded successfully'),
     onSuccess: () => {
-      toast.success(t('export.success', 'Export downloaded successfully'));
+      menuModal.close();
-      setIsOpen(false);
     },
-    onError: (error: Error) => {
+    errorMessage: (error: Error) => t('export.error', 'Export failed: ') + error.message
-      toast.error(t('export.error', 'Export failed: ') + error.message);
-    }
   });
 
   const previewMutation = useMutation({
@@ -79,7 +78,7 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
       })),
     onSuccess: (result) => {
       setPreview(result);
-      setIsOpen(false);
+      menuModal.close();
     },
     onError: (error: Error) => {
       toast.error(t('export.error', 'Export failed: ') + error.message);
@@ -145,7 +144,7 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
     <div className="relative">
       <button
         type="button"
-        onClick={() => setIsOpen(!isOpen)}
+        onClick={menuModal.toggle}
         disabled={isDisabled || isWorking}
         className={`
           inline-flex items-center gap-2 px-4 py-2 rounded-lg border font-medium text-sm
@@ -167,15 +166,15 @@ export const PhotoExportMenu: React.FC<PhotoExportMenuProps> = ({
             {selectedPhotoIds.length}
           </span>
         )}
-        <ChevronDown className={`w-4 h-4 transition-transform ${isOpen ? 'rotate-180' : ''}`} />
+        <ChevronDown className={`w-4 h-4 transition-transform ${menuModal.isOpen ? 'rotate-180' : ''}`} />
       </button>
 
-      {isOpen && !isDisabled && (
+      {menuModal.isOpen && !isDisabled && (
         <>
           {/* Backdrop */}
           <div
             className="fixed inset-0 z-10"
-            onClick={() => setIsOpen(false)}
+            onClick={menuModal.close}
           />
 
           {/* Dropdown Menu */}

frontend/src/components/admin/VatCodesManager.tsx

@@ -8,14 +8,14 @@
  * keys, and the two never overwrite each other.
  */
 import React, { useEffect, useMemo, useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
-import { toast } from 'react-toastify';
 import { X, Plus, Pencil, Trash2 } from 'lucide-react';
 import { Button, Card, CardContent, Input, Loading } from '../common';
 import {
   ledgerService, type LedgerAccount, type VatCode, type VatDirection, type LedgerSettings,
 } from '../../services/ledger.service';
+import { useMutationWithToast } from '../../hooks';
 
 const labelCls = 'block text-xs font-medium text-neutral-700 dark:text-neutral-300 mb-1';
 const selectCls = 'w-full rounded-md border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 px-3 py-2 text-sm';
@@ -39,13 +39,14 @@ const VatModal: React.FC<{ vat?: VatCode; accounts: LedgerAccount[]; onClose: ()
   const [rate, setRate] = useState<string>(vat ? String(vat.rate) : '8.1');
   const [direction, setDirection] = useState<VatDirection>(vat?.direction ?? 'input');
   const [accountId, setAccountId] = useState<number | ''>(vat?.account_id ?? '');
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => {
       const payload = { code, name, rate: Number(rate) || 0, direction, accountId: accountId === '' ? null : Number(accountId) };
       return isEdit ? ledgerService.updateVatCode(vat!.id, payload) : ledgerService.createVatCode(payload);
     },
-    onSuccess: () => { toast.success(t('common.saved', 'Saved.')); onDone(); },
+    successMessage: t('common.saved', 'Saved.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    onSuccess: () => onDone(),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
   return (
     <div className="fixed inset-0 z-50 flex items-start justify-center bg-black/50 p-4">
@@ -122,19 +123,21 @@ export const VatCodesManager: React.FC = () => {
 
   const refetch = () => { qc.invalidateQueries({ queryKey: ['ledger-vat-codes'] }); qc.invalidateQueries({ queryKey: ['ledger-mappings'] }); };
 
-  const delVat = useMutation({
+  const delVat = useMutationWithToast({
     mutationFn: (id: number) => ledgerService.deleteVatCode(id),
-    onSuccess: () => { toast.success(t('common.deleted', 'Deleted.')); refetch(); },
+    successMessage: t('common.deleted', 'Deleted.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    onSuccess: () => refetch(),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
   // PARTIAL save — only the two map keys, never the account keys.
-  const saveMaps = useMutation({
+  const saveMaps = useMutationWithToast({
     mutationFn: () => ledgerService.updateSettings({
       ledger_vat_map: maps.ledger_vat_map || {},
       ledger_output_vat_map: maps.ledger_output_vat_map || {},
     }),
-    onSuccess: () => { toast.success(t('ledger.settingsSaved', 'Mappings saved.')); qc.invalidateQueries({ queryKey: ['ledger-mappings'] }); },
+    successMessage: t('ledger.settingsSaved', 'Mappings saved.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    invalidateKeys: [['ledger-mappings']],
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
 
   const setVatMap = (tt: string, code: string) => setMaps((s) => ({ ...s, ledger_vat_map: { ...(s.ledger_vat_map || {}), [tt]: code } }));

frontend/src/components/admin/WhatsNewBanner.tsx

@@ -14,11 +14,12 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import { Sparkles, X, ExternalLink, ChevronRight } from 'lucide-react';
 import { adminService } from '../../services/admin.service';
+import { useModal } from '../../hooks';
 
 export const WhatsNewBanner: React.FC = () => {
   const { t } = useTranslation();
   const qc = useQueryClient();
-  const [open, setOpen] = useState(false);
+  const detailsModal = useModal();
   const [hidden, setHidden] = useState(false);
 
   const { data } = useQuery({
@@ -31,7 +32,7 @@ export const WhatsNewBanner: React.FC = () => {
     mutationFn: () => adminService.markWhatsNewSeen(),
     onSuccess: () => {
       setHidden(true);
-      setOpen(false);
+      detailsModal.close();
       qc.invalidateQueries({ queryKey: ['whatsnew'] });
     },
   });
@@ -56,7 +57,7 @@ export const WhatsNewBanner: React.FC = () => {
               </ul>
               <div className="mt-2">
                 <button
-                  onClick={() => setOpen(true)}
+                  onClick={detailsModal.open}
                   className="inline-flex items-center text-xs font-medium text-white bg-green-600 hover:bg-green-700 px-3 py-1.5 rounded-md transition-colors"
                 >
                   {t('admin.whatsnew.viewAll', "What's new")}
@@ -75,10 +76,10 @@ export const WhatsNewBanner: React.FC = () => {
         </div>
       </div>
 
-      {open && (
+      {detailsModal.isOpen && (
         <div
           className="fixed inset-0 z-50 flex items-center justify-center bg-black/40 p-4"
-          onClick={() => setOpen(false)}
+          onClick={detailsModal.close}
         >
           <div
             className="bg-white dark:bg-neutral-800 rounded-lg shadow-xl max-w-lg w-full max-h-[80vh] overflow-auto p-6"
@@ -89,7 +90,7 @@ export const WhatsNewBanner: React.FC = () => {
                 <Sparkles className="w-5 h-5 text-green-600" />
                 {t('admin.whatsnew.modalTitle', "What's new")}
               </h3>
-              <button onClick={() => setOpen(false)} className="p-1 text-neutral-400 hover:text-neutral-600 dark:hover:text-neutral-200">
+              <button onClick={detailsModal.close} className="p-1 text-neutral-400 hover:text-neutral-600 dark:hover:text-neutral-200">
                 <X className="w-5 h-5" />
               </button>
             </div>

frontend/src/components/admin/WordFilterManager.tsx

@@ -15,6 +15,7 @@ import {
 import { toast } from 'react-toastify';
 import { Card, Button, Input, Loading } from '../common';
 import { feedbackService } from '../../services/feedback.service';
+import { useMutationWithToast } from '../../hooks';
 
 interface WordFilter {
   id: number;
@@ -62,29 +63,23 @@ export const WordFilterManager: React.FC = () => {
   });
 
   // Update word filter mutation
-  const updateMutation = useMutation({
+  const updateMutation = useMutationWithToast({
     mutationFn: ({ id, updates }: { id: number; updates: Partial<WordFilter> }) =>
       feedbackService.updateWordFilter(id, updates),
+    invalidateKeys: [['word-filters']],
+    successMessage: t('settings.moderation.filterUpdated', 'Word filter updated successfully'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['word-filters'] });
-      toast.success(t('settings.moderation.filterUpdated', 'Word filter updated successfully'));
       setEditingId(null);
     },
-    onError: () => {
+    errorMessage: () => t('settings.moderation.updateError', 'Failed to update word filter')
-      toast.error(t('settings.moderation.updateError', 'Failed to update word filter'));
-    }
   });
 
   // Delete word filter mutation
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (id: number) => feedbackService.deleteWordFilter(id),
-    onSuccess: () => {
+    invalidateKeys: [['word-filters']],
-      queryClient.invalidateQueries({ queryKey: ['word-filters'] });
+    successMessage: t('settings.moderation.filterDeleted', 'Word filter deleted successfully'),
-      toast.success(t('settings.moderation.filterDeleted', 'Word filter deleted successfully'));
+    errorMessage: () => t('settings.moderation.deleteError', 'Failed to delete word filter')
-    },
-    onError: () => {
-      toast.error(t('settings.moderation.deleteError', 'Failed to delete word filter'));
-    }
   });
 
   const handleAdd = () => {

frontend/src/hooks/index.ts

@@ -3,3 +3,5 @@ export * from './useOnClickOutside';
 export * from './useLocalizedDate';
 export * from './usePermission';
 export * from './usePublicSettings';
+export * from './useMutationWithToast';
+export * from './useModal';

frontend/src/hooks/useModal.ts

@@ -0,0 +1,20 @@
+import { useCallback, useState } from 'react';
+
+export interface UseModalResult {
+  isOpen: boolean;
+  open: () => void;
+  close: () => void;
+  toggle: () => void;
+}
+
+/**
+ * Small helper for the ubiquitous `const [showX, setShowX] = useState(false)`
+ * modal open/close flag.
+ */
+export function useModal(initialOpen = false): UseModalResult {
+  const [isOpen, setIsOpen] = useState(initialOpen);
+  const open = useCallback(() => setIsOpen(true), []);
+  const close = useCallback(() => setIsOpen(false), []);
+  const toggle = useCallback(() => setIsOpen((prev) => !prev), []);
+  return { isOpen, open, close, toggle };
+}

frontend/src/hooks/useMutationWithToast.ts

@@ -0,0 +1,73 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+import type { QueryKey, UseMutationOptions, UseMutationResult } from '@tanstack/react-query';
+import { toast } from 'react-toastify';
+
+/**
+ * Extracts the server-provided error message from an axios error response,
+ * matching the `error.response?.data?.error` pattern used across admin pages.
+ */
+const extractServerError = (error: unknown): string | undefined => {
+  const serverError = (error as { response?: { data?: { error?: unknown; message?: unknown } } })
+    ?.response?.data;
+  if (typeof serverError?.error === 'string') return serverError.error;
+  if (typeof serverError?.message === 'string') return serverError.message;
+  return undefined;
+};
+
+export interface UseMutationWithToastOptions<TData, TError, TVariables, TContext>
+  extends UseMutationOptions<TData, TError, TVariables, TContext> {
+  /** Toast shown on success. Omit to show no success toast. */
+  successMessage?: string | ((data: TData, variables: TVariables) => string);
+  /**
+   * Fallback toast shown on error when the server response carries no error
+   * message. Pass a function to take full control of the error text.
+   */
+  errorMessage?: string | ((error: TError) => string);
+  /** Query keys invalidated on success, before the passthrough `onSuccess` runs. */
+  invalidateKeys?: QueryKey[];
+}
+
+/**
+ * `useMutation` wrapper for the common admin mutation shape:
+ * invalidate queries + success toast on success, error toast (server message
+ * first, then `errorMessage` fallback) on error. Passthrough `onSuccess` /
+ * `onError` still run after the built-in handling.
+ */
+export function useMutationWithToast<
+  TData = unknown,
+  TError = Error,
+  TVariables = void,
+  TContext = unknown,
+>(
+  options: UseMutationWithToastOptions<TData, TError, TVariables, TContext>
+): UseMutationResult<TData, TError, TVariables, TContext> {
+  const queryClient = useQueryClient();
+  const { successMessage, errorMessage, invalidateKeys, onSuccess, onError, ...mutationOptions } =
+    options;
+
+  return useMutation<TData, TError, TVariables, TContext>({
+    ...mutationOptions,
+    onSuccess: (data, variables, context) => {
+      invalidateKeys?.forEach((queryKey) => {
+        queryClient.invalidateQueries({ queryKey });
+      });
+      if (successMessage) {
+        toast.success(
+          typeof successMessage === 'function' ? successMessage(data, variables) : successMessage
+        );
+      }
+      onSuccess?.(data, variables, context);
+    },
+    onError: (error, variables, context) => {
+      const message =
+        typeof errorMessage === 'function'
+          ? errorMessage(error)
+          : extractServerError(error) ||
+            errorMessage ||
+            (error instanceof Error ? error.message : undefined) ||
+            'An unexpected error occurred';
+      toast.error(message);
+      onError?.(error, variables, context);
+    },
+  });
+}

frontend/src/pages/admin/AdminDashboard.tsx

@@ -17,14 +17,14 @@ import {
 } from 'lucide-react';
 import { differenceInDays, parseISO } from 'date-fns';
 import { useTranslation } from 'react-i18next';
-import { toast } from 'react-toastify';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 
 import { Button, Card, Loading } from '../../components/common';
 import { UpdateNotification } from '../../components/admin/UpdateNotification';
 import { WhatsNewBanner } from '../../components/admin/WhatsNewBanner';
 import { CrmOverviewSection } from '../../components/admin/CrmOverviewSection';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { eventsService } from '../../services/events.service';
 import { adminService, ActivityType } from '../../services/admin.service';
 import { workflowsService } from '../../services/workflows.service';
@@ -82,19 +82,16 @@ export const AdminDashboard: React.FC = () => {
   // Pending workflow approvals — only when the workflow engine is live. These
   // are the human-in-the-loop gates (e.g. "review invoice before sending").
   const { flags } = useFeatureFlags();
-  const qc = useQueryClient();
   const { data: pendingApprovals } = useQuery({
     queryKey: ['workflow-approvals'],
     queryFn: () => workflowsService.approvals(),
     enabled: !!flags.workflows,
   });
-  const approvalMutation = useMutation({
+  const approvalMutation = useMutationWithToast({
     mutationFn: ({ id, action }: { id: number; action: 'confirm' | 'deny' }) => workflowsService.actApproval(id, action),
-    onSuccess: () => {
+    invalidateKeys: [['workflow-approvals']],
-      qc.invalidateQueries({ queryKey: ['workflow-approvals'] });
+    successMessage: t('workflows.approvals.acted', 'Done') as string,
-      toast.success(t('workflows.approvals.acted', 'Done') as string);
+    errorMessage: t('common.error', 'Something went wrong') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('common.error', 'Something went wrong') as string)),
   });
 
   // Admin detail route for an approval's run entity, so clicking opens the

frontend/src/pages/admin/ArchivesPage.tsx

@@ -16,10 +16,11 @@ import { format, parseISO, isValid } from 'date-fns';
 import { toast } from 'react-toastify';
 
 import { Button, Input, Card, Loading } from '../../components/common';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { archiveService } from '../../services/archive.service';
 import { useTranslation } from 'react-i18next';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 // import { useNavigate } from 'react-router-dom';
 
 export const ArchivesPage: React.FC = () => {
@@ -30,7 +31,6 @@ export const ArchivesPage: React.FC = () => {
   const [sortBy, setSortBy] = useState<'date' | 'size' | 'name'>('date');
   const [currentPage, setCurrentPage] = useState(1);
   // const navigate = useNavigate();
-  const queryClient = useQueryClient();
 
   // Helper function to safely format dates
   const formatDate = (dateString: string | null | undefined, formatStr: string): string => {
@@ -79,26 +79,18 @@ export const ArchivesPage: React.FC = () => {
   };
 
   // Mutations
-  const restoreMutation = useMutation({
+  const restoreMutation = useMutationWithToast({
     mutationFn: (id: number) => archiveService.restoreArchive(id),
-    onSuccess: () => {
+    successMessage: t('archives.restoreSuccess'),
-      toast.success(t('archives.restoreSuccess'));
+    errorMessage: () => t('errors.somethingWentWrong'),
-      queryClient.invalidateQueries({ queryKey: ['admin-archives'] });
+    invalidateKeys: [['admin-archives']],
-    },
-    onError: () => {
-      toast.error(t('errors.somethingWentWrong'));
-    }
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (id: number) => archiveService.deleteArchive(id),
-    onSuccess: () => {
+    successMessage: t('archives.deleteSuccess'),
-      toast.success(t('archives.deleteSuccess'));
+    errorMessage: () => t('errors.somethingWentWrong'),
-      queryClient.invalidateQueries({ queryKey: ['admin-archives'] });
+    invalidateKeys: [['admin-archives']],
-    },
-    onError: () => {
-      toast.error(t('errors.somethingWentWrong'));
-    }
   });
 
   const handleDownload = async (archive: typeof archives[0]) => {

frontend/src/pages/admin/BackupManagement.tsx

@@ -13,12 +13,12 @@ import {
   ShieldCheck,
   FolderTree,
 } from 'lucide-react';
-import { toast } from 'react-toastify';
+import { useQuery } from '@tanstack/react-query';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 
 import { Button, Card, Loading } from '../../components/common';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 import { BackupDashboard } from '../../components/admin/BackupDashboard';
 import { BackupConfiguration } from '../../components/admin/BackupConfiguration';
 import { BackupHistory } from '../../components/admin/BackupHistory';
@@ -31,7 +31,6 @@ type TabId = 'dashboard' | 'configuration' | 'history' | 'restore' | 'integrity'
 
 export const BackupManagement: React.FC = () => {
   const [activeTab, setActiveTab] = useState<TabId>('dashboard');
-  const queryClient = useQueryClient();
   const { t } = useTranslation();
   const { formatDateTime: fmtDateTime } = useLocalizedDate();
 
@@ -61,34 +60,24 @@ export const BackupManagement: React.FC = () => {
     },
   });
 
-  const manualBackupMutation = useMutation({
+  const manualBackupMutation = useMutationWithToast({
     mutationFn: async () => {
       const response = await api.post('/admin/backup/run');
       return response.data;
     },
-    onSuccess: () => {
+    successMessage: t('backup.messages.backupStarted'),
-      toast.success(t('backup.messages.backupStarted'));
+    errorMessage: t('backup.messages.backupFailed'),
-      queryClient.invalidateQueries({ queryKey: ['backup-status'] });
+    invalidateKeys: [['backup-status']],
-    },
-    onError: (error: any) => {
-      const message = error.response?.data?.error || t('backup.messages.backupFailed');
-      toast.error(message);
-    },
   });
 
-  const updateConfigMutation = useMutation({
+  const updateConfigMutation = useMutationWithToast({
     mutationFn: async (config: unknown) => {
       const response = await api.put('/admin/backup/config', config);
       return response.data;
     },
-    onSuccess: () => {
+    successMessage: t('backup.messages.configUpdated'),
-      toast.success(t('backup.messages.configUpdated'));
+    errorMessage: t('backup.messages.configUpdateFailed'),
-      queryClient.invalidateQueries({ queryKey: ['backup-config'] });
+    invalidateKeys: [['backup-config']],
-    },
-    onError: (error: any) => {
-      const message = error.response?.data?.error || t('backup.messages.configUpdateFailed');
-      toast.error(message);
-    },
   });
 
   if (statusLoading || configLoading) {

frontend/src/pages/admin/BrandingPage.tsx

@@ -4,7 +4,7 @@ import { toast } from 'react-toastify';
 import { Button, Card, Input, ErrorBoundary, Loading, MarkdownContent } from '../../components/common';
 import { ThemeCustomizerEnhanced, GalleryPreview } from '../../components/admin';
 import { useTheme, type ThemeConfig, GALLERY_THEME_PRESETS } from '../../contexts/ThemeContext';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { settingsService, type BrandingSettings } from '../../services/settings.service';
 import { businessProfileService } from '../../services/businessProfile.service';
 import { useTranslation } from 'react-i18next';
@@ -13,6 +13,7 @@ import { useFeatureEnabled, useFeatureFlags } from '../../contexts/FeatureFlagsC
 import { CustomerDashboardBrandingCard } from '../../components/admin/CustomerDashboardBrandingCard';
 import { PdfTypographyCard } from '../../components/admin/PdfTypographyCard';
 import { usePublicSettings } from '../../hooks/usePublicSettings';
+import { useMutationWithToast } from '../../hooks';
 
 export const BrandingPage: React.FC = () => {
   const { t } = useTranslation();
@@ -88,33 +89,23 @@ export const BrandingPage: React.FC = () => {
   // Update branding mutation
   const queryClient = useQueryClient();
   
-  const brandingMutation = useMutation({
+  const brandingMutation = useMutationWithToast({
     mutationFn: settingsService.updateBranding,
-    onSuccess: () => {
+    successMessage: t('toast.brandingUpdated'),
-      toast.success(t('toast.brandingUpdated'));
+    errorMessage: () => t('toast.saveError'),
     // Invalidate all settings queries to refresh data
-      queryClient.invalidateQueries({ queryKey: ['admin-settings'] });
+    invalidateKeys: [['admin-settings'], ['public-settings']],
-      queryClient.invalidateQueries({ queryKey: ['public-settings'] });
-    },
-    onError: () => {
-      toast.error(t('toast.saveError'));
-    },
   });
 
   // Update theme mutation
-  const themeMutation = useMutation({
+  const themeMutation = useMutationWithToast({
     mutationFn: settingsService.updateTheme,
-    onSuccess: () => {
+    successMessage: t('toast.themeUpdated'),
-      toast.success(t('toast.themeUpdated'));
+    errorMessage: () => t('toast.saveError'),
     // Refresh both the admin settings cache (which the page reads from) and
     // the public-settings cache (which the gallery reads from) so the saved
     // theme is reflected without a manual reload (#317).
-      queryClient.invalidateQueries({ queryKey: ['admin-settings'] });
+    invalidateKeys: [['admin-settings'], ['public-settings']],
-      queryClient.invalidateQueries({ queryKey: ['public-settings'] });
-    },
-    onError: () => {
-      toast.error(t('toast.saveError'));
-    },
   });
 
   // Initialize settings from database

frontend/src/pages/admin/CMSPage.tsx

@@ -13,6 +13,7 @@ import type { CMSPage as CMSPageType } from '../../services/cms.service';
 import { settingsService, PublicSiteBranding } from '../../services/settings.service';
 import { buildResourceUrl } from '../../utils/url';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../hooks';
 
 export const CMSPage: React.FC = () => {
   const { t } = useTranslation();
@@ -221,14 +222,14 @@ export const CMSPage: React.FC = () => {
     },
     onError: () => toast.error(t('toast.uploadError')),
   });
-  const clearLogoMutation = useMutation({
+  const clearLogoMutation = useMutationWithToast({
     mutationFn: async () => cmsService.clearPageLogo(selectedPage),
+    successMessage: t('cms.logoCleared', 'Logo cleared'),
+    errorMessage: () => t('toast.saveError'),
+    invalidateKeys: [['cms-pages']],
     onSuccess: () => {
       setEditForm(prev => ({ ...prev, logo_url: null }));
-      queryClient.invalidateQueries({ queryKey: ['cms-pages'] });
-      toast.success(t('cms.logoCleared', 'Logo cleared'));
     },
-    onError: () => toast.error(t('toast.saveError')),
   });
 
   // Warn before leaving with unsaved changes

frontend/src/pages/admin/CustomerDetailPage.tsx

@@ -32,6 +32,7 @@ import { CustomerCrmPanels } from '../../components/admin/CustomerCrmPanels';
 import { HoursSection } from '../../components/admin/HoursSection';
 import { formatMoney } from '../../components/admin/LineItemsTable';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
+import { useMutationWithToast, useModal } from '../../hooks';
 import { useFeatureFlags } from '../../contexts/FeatureFlagsContext';
 
 type EditableFields =
@@ -101,13 +102,13 @@ export const CustomerDetailPage: React.FC = () => {
   };
 
   const [form, setForm] = useState<Partial<Pick<CustomerAccountDetail, EditableFields>>>({});
-  const [confirmDeactivate, setConfirmDeactivate] = useState(false);
+  const deactivateModal = useModal();
-  const [confirmErase, setConfirmErase] = useState(false);
+  const eraseModal = useModal();
   // Drives the "Manage galleries" modal launched from the Assigned
   // events card. We hold open-state here (rather than inside the
   // dialog) so the parent decides when to mount/unmount and the
   // dialog can hard-reset its internal state per open.
-  const [assignedDialogOpen, setAssignedDialogOpen] = useState(false);
+  const assignedDialog = useModal();
 
   // Hydrate the form from the fetched record once. We deliberately do NOT
   // re-sync on every refetch so an admin's in-progress edits aren't blown
@@ -187,10 +188,10 @@ export const CustomerDetailPage: React.FC = () => {
    * Confirm dialog ahead of the click is surfaced via the same modal
    * pattern as deactivate.
    */
-  const passwordResetMutation = useMutation({
+  const passwordResetMutation = useMutationWithToast({
     mutationFn: () => customerAdminService.sendPasswordReset(customerId),
-    onSuccess: () => toast.success(t('customers.detail.passwordReset.success', 'Password reset email sent')),
+    successMessage: t('customers.detail.passwordReset.success', 'Password reset email sent'),
-    onError: () => toast.error(t('customers.detail.passwordReset.error', 'Could not send password reset')),
+    errorMessage: () => t('customers.detail.passwordReset.error', 'Could not send password reset'),
   });
 
   // Promote a passive customer to active by firing the standard
@@ -219,25 +220,21 @@ export const CustomerDetailPage: React.FC = () => {
   // before the configured day. Surfaces backend errors verbatim so
   // admin sees "No pending monthly bill" / "Draft is empty" when the
   // queue isn't ready.
-  const triggerMonthlyBillMutation = useMutation({
+  const triggerMonthlyBillMutation = useMutationWithToast({
     mutationFn: () => customerAdminService.triggerMonthlyBill(customerId),
-    onSuccess: (result) => {
+    invalidateKeys: [
-      queryClient.invalidateQueries({ queryKey: ['admin-customer', customerId] });
+      ['admin-customer', customerId],
-      queryClient.invalidateQueries({ queryKey: ['admin-customer-hour-entries', customerId] });
+      ['admin-customer-hour-entries', customerId],
       // Clear the draft preview so the list collapses to empty
       // immediately after the trigger ships — a new draft is minted
       // on the next createInvoice / hour-entry append.
-      queryClient.invalidateQueries({ queryKey: ['admin-customer-monthly-draft', customerId] });
+      ['admin-customer-monthly-draft', customerId],
-      toast.success(
+    ],
+    successMessage: (result) =>
       t('customers.billing.triggered',
         'Monthly bill issued: {{number}}',
         { number: result.invoiceNumber }),
-      );
+    errorMessage: t('customers.billing.triggerError', 'Could not trigger the monthly bill.'),
-    },
-    onError: (err: any) => {
-      toast.error(err?.response?.data?.error
-        || t('customers.billing.triggerError', 'Could not trigger the monthly bill.'));
-    },
   });
 
   const deactivateMutation = useMutation({
@@ -252,14 +249,11 @@ export const CustomerDetailPage: React.FC = () => {
   });
 
   /** Re-enable login for a deactivated customer. */
-  const reactivateMutation = useMutation({
+  const reactivateMutation = useMutationWithToast({
     mutationFn: () => customerAdminService.reactivate(customerId),
-    onSuccess: () => {
+    invalidateKeys: [['admin-customer', customerId], ['admin-customers']],
-      queryClient.invalidateQueries({ queryKey: ['admin-customer', customerId] });
+    successMessage: t('customers.reactivate.success', 'Customer reactivated'),
-      queryClient.invalidateQueries({ queryKey: ['admin-customers'] });
+    errorMessage: () => t('customers.reactivate.error', 'Could not reactivate customer'),
-      toast.success(t('customers.reactivate.success', 'Customer reactivated'));
-    },
-    onError: () => toast.error(t('customers.reactivate.error', 'Could not reactivate customer')),
   });
 
   /**
@@ -466,7 +460,7 @@ export const CustomerDetailPage: React.FC = () => {
             variant="outline"
             size="sm"
             leftIcon={<SettingsIcon className="w-4 h-4" />}
-            onClick={() => setAssignedDialogOpen(true)}
+            onClick={() => assignedDialog.open()}
             disabled={!customer.isActive}
           >
             {t('customers.detail.manageEvents', 'Manage galleries')}
@@ -495,13 +489,13 @@ export const CustomerDetailPage: React.FC = () => {
 
       <AssignedEventsDialog
         customerId={customer.id}
-        isOpen={assignedDialogOpen}
+        isOpen={assignedDialog.isOpen}
         initial={customer.events.map((ev) => ({
           id: ev.id,
           eventName: ev.eventName,
           eventDate: ev.eventDate || null,
         }))}
-        onClose={() => setAssignedDialogOpen(false)}
+        onClose={() => assignedDialog.close()}
         onSaved={() => {
           // Parent refetch is handled by the dialog's invalidateQueries.
         }}
@@ -960,7 +954,7 @@ export const CustomerDetailPage: React.FC = () => {
             <Button
               variant="outline"
               leftIcon={<Trash2 className="w-4 h-4" />}
-              onClick={() => setConfirmDeactivate(true)}
+              onClick={() => deactivateModal.open()}
             >
               {t('customers.deactivate.button', 'Deactivate')}
             </Button>
@@ -981,7 +975,7 @@ export const CustomerDetailPage: React.FC = () => {
               <Button
                 variant="outline"
                 leftIcon={<Trash2 className="w-4 h-4 text-red-600" />}
-                onClick={() => setConfirmErase(true)}
+                onClick={() => eraseModal.open()}
               >
                 <span className="text-red-600">
                   {t('customers.erase.button', 'Erase customer data')}
@@ -1000,7 +994,7 @@ export const CustomerDetailPage: React.FC = () => {
         </Button>
       </div>
 
-      {confirmDeactivate && (
+      {deactivateModal.isOpen && (
         <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 px-4">
           <div className="w-full max-w-md rounded-xl shadow-lg bg-white dark:bg-neutral-900">
             <div className="p-6">
@@ -1017,13 +1011,13 @@ export const CustomerDetailPage: React.FC = () => {
                 </div>
               </div>
               <div className="flex justify-end gap-2 pt-2">
-                <Button variant="outline" onClick={() => setConfirmDeactivate(false)}>
+                <Button variant="outline" onClick={() => deactivateModal.close()}>
                   {t('common.cancel', 'Cancel')}
                 </Button>
                 <Button
                   variant="primary"
                   isLoading={deactivateMutation.isPending}
-                  onClick={() => { deactivateMutation.mutate(); setConfirmDeactivate(false); }}
+                  onClick={() => { deactivateMutation.mutate(); deactivateModal.close(); }}
                 >
                   {t('common.confirm', 'Confirm')}
                 </Button>
@@ -1037,7 +1031,7 @@ export const CustomerDetailPage: React.FC = () => {
           "irreversible" copy + red Confirm button so the click feels
           deliberate. The action anonymizes PII in place; assignments
           and audit-log references are preserved. */}
-      {confirmErase && (
+      {eraseModal.isOpen && (
         <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 px-4">
           <div className="w-full max-w-md rounded-xl shadow-lg bg-white dark:bg-neutral-900">
             <div className="p-6">
@@ -1054,14 +1048,14 @@ export const CustomerDetailPage: React.FC = () => {
                 </div>
               </div>
               <div className="flex justify-end gap-2 pt-2">
-                <Button variant="outline" onClick={() => setConfirmErase(false)}>
+                <Button variant="outline" onClick={() => eraseModal.close()}>
                   {t('common.cancel', 'Cancel')}
                 </Button>
                 <button
                   type="button"
                   className="inline-flex items-center justify-center rounded-lg px-4 py-2 text-sm font-medium text-white bg-red-600 hover:bg-red-700 disabled:opacity-60 disabled:cursor-not-allowed"
                   disabled={eraseMutation.isPending}
-                  onClick={() => { eraseMutation.mutate(); setConfirmErase(false); }}
+                  onClick={() => { eraseMutation.mutate(); eraseModal.close(); }}
                 >
                   {eraseMutation.isPending
                     ? t('customers.erase.confirmInFlight', 'Erasing…')

frontend/src/pages/admin/CustomerManagementPage.tsx

@@ -16,13 +16,13 @@
  */
 import React, { useEffect, useMemo, useState } from 'react';
 import { Link } from 'react-router-dom';
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
-import { toast } from 'react-toastify';
 import {
   UserPlus, UserCog, Trash2, Search, X, AlertTriangle, CheckCircle2, Clock,
 } from 'lucide-react';
 import { InlineCustomerCreate } from '../../components/admin/InlineCustomerCreate';
+import { useMutationWithToast } from '../../hooks';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
 
 import { Button, Card, Input, Loading } from '../../components/common';
@@ -96,22 +96,18 @@ export const CustomerManagementPage: React.FC = () => {
     return list.filter((i) => i.email.toLowerCase().includes(term));
   }, [invitations, debouncedTerm]);
 
-  const deactivateMutation = useMutation({
+  const deactivateMutation = useMutationWithToast({
     mutationFn: (id: number) => customerAdminService.deactivate(id),
-    onSuccess: () => {
+    invalidateKeys: [['admin-customers']],
-      queryClient.invalidateQueries({ queryKey: ['admin-customers'] });
+    successMessage: t('customers.deactivate.success', 'Customer deactivated'),
-      toast.success(t('customers.deactivate.success', 'Customer deactivated'));
+    errorMessage: () => t('customers.deactivate.error', 'Could not deactivate customer'),
-    },
-    onError: () => toast.error(t('customers.deactivate.error', 'Could not deactivate customer')),
   });
 
-  const cancelInviteMutation = useMutation({
+  const cancelInviteMutation = useMutationWithToast({
     mutationFn: (id: number) => customerAdminService.cancelInvitation(id),
-    onSuccess: () => {
+    invalidateKeys: [['admin-customer-invitations']],
-      queryClient.invalidateQueries({ queryKey: ['admin-customer-invitations'] });
+    successMessage: t('customers.cancelInvitation.success', 'Invitation cancelled'),
-      toast.success(t('customers.cancelInvitation.success', 'Invitation cancelled'));
+    errorMessage: () => t('customers.cancelInvitation.error', 'Could not cancel invitation'),
-    },
-    onError: () => toast.error(t('customers.cancelInvitation.error', 'Could not cancel invitation')),
   });
 
   const renderCustomerName = (c: CustomerAccountSummary) => {

frontend/src/pages/admin/EmailConfigPage.tsx

@@ -22,7 +22,8 @@ import { SentEmailsPanel } from '../../components/admin/SentEmailsPanel';
 import { ReceivedEmailsPanel } from '../../components/admin/ReceivedEmailsPanel';
 import { IncomingMailConfigCard } from '../../components/admin/IncomingMailConfigCard';
 import { Palette, RefreshCw, Info } from 'lucide-react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useMutation } from '@tanstack/react-query';
+import { useModal, useMutationWithToast } from '../../hooks';
 import { emailService, type EmailConfig, type EmailTemplate, type EmailTemplateTranslation } from '../../services/email.service';
 import { settingsService } from '../../services/settings.service';
 import { useTranslation } from 'react-i18next';
@@ -138,7 +139,7 @@ export const EmailConfigPage: React.FC = () => {
   const [editingLang, setEditingLang] = useState<string>('en');
   const [showPassword, setShowPassword] = useState(false);
   const [testEmail, setTestEmail] = useState('');
-  const [showPreview, setShowPreview] = useState(false);
+  const previewModal = useModal();
   const [previewData, setPreviewData] = useState<{ subject: string; htmlContent: string; textContent?: string }>({
     subject: '',
     htmlContent: '',
@@ -157,7 +158,6 @@ export const EmailConfigPage: React.FC = () => {
   const [emailBodyTextColor, setEmailBodyTextColor] = useState('#333333');
   const [emailMutedTextColor, setEmailMutedTextColor] = useState('#666666');
   const [emailButtonTextColor, setEmailButtonTextColor] = useState('#ffffff');
-  const queryClient = useQueryClient();
   const { flags: featureFlags } = useFeatureFlags();
 
   // SMTP Configuration state
@@ -239,25 +239,17 @@ export const EmailConfigPage: React.FC = () => {
     || e?.message
     || fallback;
 
-  const saveConfigMutation = useMutation({
+  const saveConfigMutation = useMutationWithToast({
     mutationFn: (config: EmailConfig) => emailService.updateConfig(config),
-    onSuccess: () => {
+    successMessage: t('toast.emailConfigSaved'),
-      toast.success(t('toast.emailConfigSaved'));
+    invalidateKeys: [['email-config']],
-      queryClient.invalidateQueries({ queryKey: ['email-config'] });
+    errorMessage: (e: any) => errMsg(e, t('toast.saveError')),
-    },
-    onError: (e: any) => {
-      toast.error(errMsg(e, t('toast.saveError')));
-    }
   });
 
-  const testEmailMutation = useMutation({
+  const testEmailMutation = useMutationWithToast({
     mutationFn: (email: string) => emailService.testEmail(email),
-    onSuccess: () => {
+    successMessage: t('email.testEmailSuccess'),
-      toast.success(t('email.testEmailSuccess'));
+    errorMessage: (e: any) => errMsg(e, t('toast.saveError')),
-    },
-    onError: (e: any) => {
-      toast.error(errMsg(e, t('toast.saveError')));
-    }
   });
 
   const flushQueueMutation = useMutation({
@@ -274,29 +266,20 @@ export const EmailConfigPage: React.FC = () => {
     }
   });
 
-  const saveTemplateMutation = useMutation({
+  const saveTemplateMutation = useMutationWithToast({
     mutationFn: ({ key, translations }: { key: string; translations: Record<string, EmailTemplateTranslation> }) =>
       emailService.updateTemplate(key, { translations }),
-    onSuccess: () => {
+    successMessage: t('toast.saveSuccess'),
-      toast.success(t('toast.saveSuccess'));
+    invalidateKeys: [['email-templates'], ['email-template', selectedTemplateKey]],
-      queryClient.invalidateQueries({ queryKey: ['email-templates'] });
+    errorMessage: () => t('toast.saveError'),
-      queryClient.invalidateQueries({ queryKey: ['email-template', selectedTemplateKey] });
-    },
-    onError: () => {
-      toast.error(t('toast.saveError'));
-    }
   });
 
-  const saveEmailColorsMutation = useMutation({
+  const saveEmailColorsMutation = useMutationWithToast({
     mutationFn: (colors: Record<string, string>) =>
       settingsService.updateSettings(colors),
-    onSuccess: () => {
+    successMessage: t('toast.saveSuccess'),
-      toast.success(t('toast.saveSuccess'));
+    invalidateKeys: [['admin-settings']],
-      queryClient.invalidateQueries({ queryKey: ['admin-settings'] });
+    errorMessage: () => t('toast.saveError'),
-    },
-    onError: () => {
-      toast.error(t('toast.saveError'));
-    }
   });
 
   const handleSaveEmailColors = () => {
@@ -431,7 +414,7 @@ export const EmailConfigPage: React.FC = () => {
         htmlContent: preview.body_html,
         textContent: preview.body_text
       });
-      setShowPreview(true);
+      previewModal.open();
     } catch (error) {
       toast.error(t('toast.saveError'));
     }
@@ -1057,8 +1040,8 @@ export const EmailConfigPage: React.FC = () => {
 
       {/* Email Preview Modal */}
       <EmailPreviewModal
-        isOpen={showPreview}
+        isOpen={previewModal.isOpen}
-        onClose={() => setShowPreview(false)}
+        onClose={previewModal.close}
         subject={previewData.subject}
         htmlContent={previewData.htmlContent}
         textContent={previewData.textContent}

frontend/src/pages/admin/EventFeedbackPage.tsx

@@ -25,6 +25,7 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { eventsService } from '../../services/events.service';
 import { feedbackService } from '../../services/feedback.service';
 import type { PhotoFeedback, FeedbackAnalytics, FeedbackResponse } from '../../services/feedback.service';
+import { useMutationWithToast } from '../../hooks';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
 
 export const EventFeedbackPage: React.FC = () => {
@@ -76,15 +77,11 @@ export const EventFeedbackPage: React.FC = () => {
   });
 
   // Update settings mutation
-  const updateSettingsMutation = useMutation({
+  const updateSettingsMutation = useMutationWithToast({
     mutationFn: (newSettings: any) => feedbackService.updateEventFeedbackSettings(id!, newSettings),
-    onSuccess: () => {
+    invalidateKeys: [['feedback-settings', id]],
-      queryClient.invalidateQueries({ queryKey: ['feedback-settings', id] });
+    successMessage: t('feedback.settingsUpdated', 'Feedback settings updated'),
-      toast.success(t('feedback.settingsUpdated', 'Feedback settings updated'));
+    errorMessage: () => t('feedback.settingsUpdateError', 'Failed to update settings'),
-    },
-    onError: () => {
-      toast.error(t('feedback.settingsUpdateError', 'Failed to update settings'));
-    }
   });
 
   // Moderate feedback mutation

frontend/src/pages/admin/EventTypesPage.tsx

@@ -1,6 +1,5 @@
 import React, { useState, useMemo } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { useTranslation } from 'react-i18next';
 import {
   Plus,
@@ -16,6 +15,7 @@ import {
 } from 'lucide-react';
 
 import { Button, Input, Card, Loading } from '../../components/common';
+import { useModal, useMutationWithToast } from '../../hooks';
 import { eventTypesService, EventType, CreateEventTypeData, UpdateEventTypeData } from '../../services/eventTypes.service';
 import { GALLERY_THEME_PRESETS } from '../../types/theme.types';
 
@@ -27,12 +27,11 @@ const EMOJI_OPTIONS = [
 
 export const EventTypesPage: React.FC = () => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
 
   // State
   const [searchTerm, setSearchTerm] = useState('');
   const [showInactive, setShowInactive] = useState(false);
-  const [showCreateModal, setShowCreateModal] = useState(false);
+  const createModal = useModal();
   const [editingType, setEditingType] = useState<EventType | null>(null);
   const [deleteConfirm, setDeleteConfirm] = useState<EventType | null>(null);
 
@@ -43,40 +42,34 @@ export const EventTypesPage: React.FC = () => {
   });
 
   // Mutations
-  const createMutation = useMutation({
+  const createMutation = useMutationWithToast({
     mutationFn: eventTypesService.createEventType,
+    invalidateKeys: [['admin-event-types']],
+    successMessage: t('eventTypes.created', 'Event type created successfully'),
+    errorMessage: t('eventTypes.createError', 'Failed to create event type'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-event-types'] });
+      createModal.close();
-      setShowCreateModal(false);
-      toast.success(t('eventTypes.created', 'Event type created successfully'));
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('eventTypes.createError', 'Failed to create event type'));
     }
   });
 
-  const updateMutation = useMutation({
+  const updateMutation = useMutationWithToast({
     mutationFn: ({ id, data }: { id: number; data: UpdateEventTypeData }) =>
       eventTypesService.updateEventType(id, data),
+    invalidateKeys: [['admin-event-types']],
+    successMessage: t('eventTypes.updated', 'Event type updated successfully'),
+    errorMessage: t('eventTypes.updateError', 'Failed to update event type'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-event-types'] });
       setEditingType(null);
-      toast.success(t('eventTypes.updated', 'Event type updated successfully'));
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('eventTypes.updateError', 'Failed to update event type'));
     }
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: eventTypesService.deleteEventType,
+    invalidateKeys: [['admin-event-types']],
+    successMessage: t('eventTypes.deleted', 'Event type deleted successfully'),
+    errorMessage: t('eventTypes.deleteError', 'Failed to delete event type'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-event-types'] });
       setDeleteConfirm(null);
-      toast.success(t('eventTypes.deleted', 'Event type deleted successfully'));
-    },
-    onError: (error: any) => {
-      toast.error(error.response?.data?.error || t('eventTypes.deleteError', 'Failed to delete event type'));
     }
   });
 
@@ -130,7 +123,7 @@ export const EventTypesPage: React.FC = () => {
           <Button
             variant="primary"
             leftIcon={<Plus className="w-4 h-4" />}
-            onClick={() => setShowCreateModal(true)}
+            onClick={() => createModal.open()}
           >
             {t('eventTypes.createNew', 'New Event Type')}
           </Button>
@@ -274,9 +267,9 @@ export const EventTypesPage: React.FC = () => {
       </div>
 
       {/* Create Modal */}
-      {showCreateModal && (
+      {createModal.isOpen && (
         <EventTypeModal
-          onClose={() => setShowCreateModal(false)}
+          onClose={createModal.close}
           onSubmit={(data) => createMutation.mutate(data as CreateEventTypeData)}
           isLoading={createMutation.isPending}
         />

frontend/src/pages/admin/EventsListPage.tsx

@@ -20,6 +20,7 @@ import {
 } from 'lucide-react';
 import { parseISO, differenceInDays } from 'date-fns';
 import { toast } from 'react-toastify';
+import { useModal, useMutationWithToast } from '../../hooks';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
 
 import { Button, Input, Card, SkeletonTable, ErrorBoundary } from '../../components/common';
@@ -46,8 +47,8 @@ export const EventsListPage: React.FC = () => {
   // const [showFilters, setShowFilters] = useState(false);
   const [activeDropdown, setActiveDropdown] = useState<number | null>(null);
   const [dropdownPosition, setDropdownPosition] = useState<{ top: number; left: number } | null>(null);
-  const [showBulkArchiveModal, setShowBulkArchiveModal] = useState(false);
+  const bulkArchiveModal = useModal();
-  const [showBulkDeleteModal, setShowBulkDeleteModal] = useState(false);
+  const bulkDeleteModal = useModal();
   const [copiedEventId, setCopiedEventId] = useState<number | null>(null);
 
   const copyShareLink = async (event: Event) => {
@@ -169,29 +170,19 @@ export const EventsListPage: React.FC = () => {
   });
 
   // Archive mutation
-  const archiveMutation = useMutation({
+  const archiveMutation = useMutationWithToast({
     mutationFn: eventsService.archiveEvent,
-    onSuccess: () => {
+    invalidateKeys: [['admin-events'], ['admin-dashboard-stats']],
-      queryClient.invalidateQueries({ queryKey: ['admin-events'] });
+    successMessage: t('toast.eventArchived'),
-      queryClient.invalidateQueries({ queryKey: ['admin-dashboard-stats'] });
+    errorMessage: () => t('toast.saveError'),
-      toast.success(t('toast.eventArchived'));
-    },
-    onError: () => {
-      toast.error(t('toast.saveError'));
-    },
   });
 
   // Delete mutation
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: eventsService.deleteEvent,
-    onSuccess: () => {
+    invalidateKeys: [['admin-events'], ['admin-dashboard-stats']],
-      queryClient.invalidateQueries({ queryKey: ['admin-events'] });
+    successMessage: t('toast.deleteSuccess'),
-      queryClient.invalidateQueries({ queryKey: ['admin-dashboard-stats'] });
+    errorMessage: () => t('toast.deleteError'),
-      toast.success(t('toast.deleteSuccess'));
-    },
-    onError: () => {
-      toast.error(t('toast.deleteError'));
-    },
   });
 
   // Bulk archive mutation
@@ -201,7 +192,7 @@ export const EventsListPage: React.FC = () => {
       queryClient.invalidateQueries({ queryKey: ['admin-events'] });
       queryClient.invalidateQueries({ queryKey: ['admin-dashboard-stats'] });
       setSelectedEvents([]);
-      setShowBulkArchiveModal(false);
+      bulkArchiveModal.close();
 
       if (data.results.failed.length === 0) {
         toast.success(t('events.bulkArchiveSuccess', { count: data.results.successful.length }));
@@ -222,7 +213,7 @@ export const EventsListPage: React.FC = () => {
       queryClient.invalidateQueries({ queryKey: ['admin-events'] });
       queryClient.invalidateQueries({ queryKey: ['admin-dashboard-stats'] });
       setSelectedEvents([]);
-      setShowBulkDeleteModal(false);
+      bulkDeleteModal.close();
 
       if (data.results.failed.length === 0) {
         toast.success(t('events.bulkDelete.successAll', { count: data.results.successful.length }));
@@ -232,7 +223,7 @@ export const EventsListPage: React.FC = () => {
     },
     onError: () => {
       toast.error(t('events.bulkDelete.errorGeneric'));
-      setShowBulkDeleteModal(false);
+      bulkDeleteModal.close();
     },
   });
 
@@ -439,14 +430,14 @@ export const EventsListPage: React.FC = () => {
               <Button
                 variant="outline"
                 size="sm"
-                onClick={() => setShowBulkArchiveModal(true)}
+                onClick={() => bulkArchiveModal.open()}
               >
                 {t('events.archiveSelected')}
               </Button>
               <Button
                 variant="outline"
                 size="sm"
-                onClick={() => setShowBulkDeleteModal(true)}
+                onClick={() => bulkDeleteModal.open()}
                 className="border-red-300 text-red-700 hover:bg-red-50 dark:border-red-700 dark:text-red-400 dark:hover:bg-red-900/30"
               >
                 {t('events.deleteSelected', 'Delete Selected')}
@@ -758,8 +749,8 @@ export const EventsListPage: React.FC = () => {
 
       {/* Bulk Archive Modal */}
       <BulkArchiveModal
-        isOpen={showBulkArchiveModal}
+        isOpen={bulkArchiveModal.isOpen}
-        onClose={() => setShowBulkArchiveModal(false)}
+        onClose={bulkArchiveModal.close}
         onConfirm={() => bulkArchiveMutation.mutate(selectedEvents)}
         selectedEvents={events.filter(e => selectedEvents.includes(e.id))}
         isLoading={bulkArchiveMutation.isPending}
@@ -767,8 +758,8 @@ export const EventsListPage: React.FC = () => {
 
       {/* Bulk Delete Modal */}
       <BulkDeleteModal
-        isOpen={showBulkDeleteModal}
+        isOpen={bulkDeleteModal.isOpen}
-        onClose={() => setShowBulkDeleteModal(false)}
+        onClose={bulkDeleteModal.close}
         onConfirm={async () => {
           await bulkDeleteMutation.mutateAsync(selectedEvents);
         }}

frontend/src/pages/admin/SystemHealthPage.tsx

@@ -5,34 +5,33 @@
  */
 import React from 'react';
 import { useTranslation } from 'react-i18next';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { AlertCircle, RefreshCw, Trash2, CheckCircle } from 'lucide-react';
 import { Button, Card, Loading } from '../../components/common';
+import { useMutationWithToast } from '../../hooks';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
 import { systemHealthService } from '../../services/systemHealth.service';
 
 export const SystemHealthPage: React.FC = () => {
   const { t } = useTranslation();
   const { formatDateTime: fmtDateTime } = useLocalizedDate();
-  const qc = useQueryClient();
 
   const { data, isLoading } = useQuery({
     queryKey: ['system-health-failures'],
     queryFn: () => systemHealthService.getFailures(),
   });
 
-  const invalidate = () => qc.invalidateQueries({ queryKey: ['system-health-failures'] });
+  const retryMutation = useMutationWithToast({
-
-  const retryMutation = useMutation({
     mutationFn: (id: number) => systemHealthService.retryEmail(id),
-    onSuccess: () => { toast.success(t('systemHealth.retriedToast', 'Email re-queued.')); invalidate(); },
+    invalidateKeys: [['system-health-failures']],
-    onError: () => toast.error(t('toast.saveError')),
+    successMessage: t('systemHealth.retriedToast', 'Email re-queued.'),
+    errorMessage: () => t('toast.saveError'),
   });
-  const dismissMutation = useMutation({
+  const dismissMutation = useMutationWithToast({
     mutationFn: (id: number) => systemHealthService.dismissEmail(id),
-    onSuccess: () => { toast.success(t('systemHealth.dismissedToast', 'Dismissed.')); invalidate(); },
+    invalidateKeys: [['system-health-failures']],
-    onError: () => toast.error(t('toast.saveError')),
+    successMessage: t('systemHealth.dismissedToast', 'Dismissed.'),
+    errorMessage: () => t('toast.saveError'),
   });
 
   const stuckEmails = data?.stuckEmails ?? [];

frontend/src/pages/admin/UserManagementPage.tsx

@@ -1,7 +1,6 @@
 import React, { useState, useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import {
   Users,
   Mail,
@@ -23,7 +22,7 @@ import { parseISO, isPast } from 'date-fns';
 import { Button, Input, Card, Loading } from '../../components/common';
 import { userManagementService } from '../../services/userManagement.service';
 import type { AdminUser, AdminRole, AdminInvitation } from '../../types';
-import { useLocalizedDate } from "../../hooks";
+import { useLocalizedDate, useModal, useMutationWithToast } from "../../hooks";
 
 type TabType = 'users' | 'invitations';
 
@@ -369,14 +368,13 @@ const ConfirmDialog: React.FC<ConfirmDialogProps> = ({
 
 export const UserManagementPage: React.FC = () => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
   const { formatDistanceToNow } = useLocalizedDate()
 
   // State
   const [activeTab, setActiveTab] = useState<TabType>('users');
   const [searchTerm, setSearchTerm] = useState('');
-  const [showCreateInvitationModal, setShowCreateInvitationModal] = useState(false);
+  const createInvitationModal = useModal();
-  const [showEditUserModal, setShowEditUserModal] = useState(false);
+  const editUserModal = useModal();
   const [selectedUser, setSelectedUser] = useState<AdminUser | null>(null);
   const [confirmDialog, setConfirmDialog] = useState<{
     isOpen: boolean;
@@ -413,80 +411,68 @@ export const UserManagementPage: React.FC = () => {
   });
 
   // Mutations
-  const createInvitationMutation = useMutation({
+  const createInvitationMutation = useMutationWithToast({
     mutationFn: ({ email, roleId }: { email: string; roleId: number }) =>
       userManagementService.createInvitation({ email, role_id: roleId }),
+    invalidateKeys: [['admin-invitations']],
+    successMessage: t('userManagement.invitationSent'),
+    errorMessage: (error: Error) => error.message || t('userManagement.invitationError'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-invitations'] });
+      createInvitationModal.close();
-      setShowCreateInvitationModal(false);
-      toast.success(t('userManagement.invitationSent'));
-    },
-    onError: (error: Error) => {
-      toast.error(error.message || t('userManagement.invitationError'));
     },
   });
 
-  const cancelInvitationMutation = useMutation({
+  const cancelInvitationMutation = useMutationWithToast({
     mutationFn: userManagementService.cancelInvitation,
+    invalidateKeys: [['admin-invitations']],
+    successMessage: t('userManagement.invitationCancelled'),
+    errorMessage: () => t('userManagement.cancelInvitationError'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-invitations'] });
       setConfirmDialog(null);
-      toast.success(t('userManagement.invitationCancelled'));
-    },
-    onError: () => {
-      toast.error(t('userManagement.cancelInvitationError'));
     },
   });
 
-  const updateUserMutation = useMutation({
+  const updateUserMutation = useMutationWithToast({
     mutationFn: ({ id, roleId }: { id: number; roleId: number }) =>
       userManagementService.updateUser(id, { roleId }),
+    invalidateKeys: [['admin-users']],
+    successMessage: t('userManagement.userUpdated'),
+    errorMessage: () => t('userManagement.updateUserError'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-users'] });
+      editUserModal.close();
-      setShowEditUserModal(false);
       setSelectedUser(null);
-      toast.success(t('userManagement.userUpdated'));
-    },
-    onError: () => {
-      toast.error(t('userManagement.updateUserError'));
     },
   });
 
-  const deactivateUserMutation = useMutation({
+  const deactivateUserMutation = useMutationWithToast({
     mutationFn: userManagementService.deactivateUser,
+    invalidateKeys: [['admin-users']],
+    successMessage: t('userManagement.userDeactivated'),
+    errorMessage: () => t('userManagement.deactivateUserError'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-users'] });
       setConfirmDialog(null);
-      toast.success(t('userManagement.userDeactivated'));
-    },
-    onError: () => {
-      toast.error(t('userManagement.deactivateUserError'));
     },
   });
 
   // #574 follow-up: reactivate + delete actions for the rows the
   // deactivate button used to leave unmanageable.
-  const activateUserMutation = useMutation({
+  const activateUserMutation = useMutationWithToast({
     mutationFn: userManagementService.activateUser,
+    invalidateKeys: [['admin-users']],
+    successMessage: t('userManagement.userActivated', 'User reactivated successfully'),
+    errorMessage: () => t('userManagement.activateUserError', 'Failed to reactivate user'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-users'] });
       setConfirmDialog(null);
-      toast.success(t('userManagement.userActivated', 'User reactivated successfully'));
-    },
-    onError: () => {
-      toast.error(t('userManagement.activateUserError', 'Failed to reactivate user'));
     },
   });
 
-  const deleteUserMutation = useMutation({
+  const deleteUserMutation = useMutationWithToast({
     mutationFn: userManagementService.deleteUser,
+    invalidateKeys: [['admin-users']],
+    successMessage: t('userManagement.userDeleted', 'User deleted successfully'),
+    errorMessage: () => t('userManagement.deleteUserError', 'Failed to delete user'),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['admin-users'] });
       setConfirmDialog(null);
-      toast.success(t('userManagement.userDeleted', 'User deleted successfully'));
-    },
-    onError: () => {
-      toast.error(t('userManagement.deleteUserError', 'Failed to delete user'));
     },
   });
 
@@ -523,7 +509,7 @@ export const UserManagementPage: React.FC = () => {
 
   const handleEditUser = (user: AdminUser) => {
     setSelectedUser(user);
-    setShowEditUserModal(true);
+    editUserModal.open();
   };
 
   const handleUpdateUser = (userId: number, roleId: number) => {
@@ -641,7 +627,7 @@ export const UserManagementPage: React.FC = () => {
         <Button
           variant="primary"
           leftIcon={<Plus className="w-5 h-5" />}
-          onClick={() => setShowCreateInvitationModal(true)}
+          onClick={createInvitationModal.open}
         >
           {t('userManagement.inviteUser')}
         </Button>
@@ -983,8 +969,8 @@ export const UserManagementPage: React.FC = () => {
 
       {/* Create Invitation Modal */}
       <CreateInvitationModal
-        isOpen={showCreateInvitationModal}
+        isOpen={createInvitationModal.isOpen}
-        onClose={() => setShowCreateInvitationModal(false)}
+        onClose={createInvitationModal.close}
         onSubmit={handleCreateInvitation}
         roles={roles || []}
         isLoading={createInvitationMutation.isPending}
@@ -992,9 +978,9 @@ export const UserManagementPage: React.FC = () => {
 
       {/* Edit User Modal */}
       <EditUserModal
-        isOpen={showEditUserModal}
+        isOpen={editUserModal.isOpen}
         onClose={() => {
-          setShowEditUserModal(false);
+          editUserModal.close();
           setSelectedUser(null);
         }}
         onSubmit={handleUpdateUser}

frontend/src/pages/admin/WebhookDeliveriesPage.tsx

@@ -1,10 +1,10 @@
 import React, { useState } from 'react';
 import { useParams, Link } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { ArrowLeft, RefreshCw, RotateCw, Send, X, AlertCircle, CheckCircle2, Clock } from 'lucide-react';
 import { Button, Card, Loading } from '../../components/common';
 import { api } from '../../config/api';
+import { useModal, useMutationWithToast } from '../../hooks';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
 
 const WEBHOOK_EVENT_TYPES = [
@@ -64,12 +64,11 @@ function statusBadge(status: string) {
 export const WebhookDeliveriesPage: React.FC = () => {
   const { id } = useParams<{ id: string }>();
   const webhookId = parseInt(id || '', 10);
-  const queryClient = useQueryClient();
   const { formatDateTime: fmtDateTime } = useLocalizedDate();
 
   const [filter, setFilter] = useState<StatusFilter>('all');
   const [openDeliveryId, setOpenDeliveryId] = useState<number | null>(null);
-  const [showTestDialog, setShowTestDialog] = useState(false);
+  const testDialog = useModal();
   const [testEventType, setTestEventType] = useState<string>('event.published');
 
   const { data: webhook, isLoading: loadingWebhook } = useQuery({
@@ -108,24 +107,22 @@ export const WebhookDeliveriesPage: React.FC = () => {
     enabled: Number.isFinite(webhookId) && openDeliveryId !== null,
   });
 
-  const replayMutation = useMutation({
+  const replayMutation = useMutationWithToast({
     mutationFn: async (deliveryId: number) =>
       api.post(`/admin/webhooks/${webhookId}/deliveries/${deliveryId}/replay`),
-    onSuccess: () => {
+    invalidateKeys: [['admin-webhook-deliveries', webhookId]],
-      toast.success('Replay enqueued');
+    successMessage: 'Replay enqueued',
-      queryClient.invalidateQueries({ queryKey: ['admin-webhook-deliveries', webhookId] });
+    errorMessage: () => 'Failed to replay',
-    },
-    onError: () => toast.error('Failed to replay'),
   });
 
-  const testMutation = useMutation({
+  const testMutation = useMutationWithToast({
     mutationFn: async () => api.post(`/admin/webhooks/${webhookId}/test`, { event_type: testEventType }),
+    invalidateKeys: [['admin-webhook-deliveries', webhookId]],
+    successMessage: 'Test event enqueued',
+    errorMessage: 'Failed to send test',
     onSuccess: () => {
-      toast.success('Test event enqueued');
+      testDialog.close();
-      setShowTestDialog(false);
-      queryClient.invalidateQueries({ queryKey: ['admin-webhook-deliveries', webhookId] });
     },
-    onError: (err: any) => toast.error(err?.response?.data?.error || 'Failed to send test'),
   });
 
   if (loadingWebhook) {
@@ -174,7 +171,7 @@ export const WebhookDeliveriesPage: React.FC = () => {
             variant="outline"
             size="sm"
             leftIcon={<Send className="w-4 h-4" />}
-            onClick={() => setShowTestDialog(true)}
+            onClick={() => testDialog.open()}
           >
             Send test event
           </Button>
@@ -338,8 +335,8 @@ export const WebhookDeliveriesPage: React.FC = () => {
       )}
 
       {/* Test event dialog */}
-      {showTestDialog && (
+      {testDialog.isOpen && (
-        <div className="fixed inset-0 z-40 flex items-center justify-center bg-black/40" onClick={() => setShowTestDialog(false)}>
+        <div className="fixed inset-0 z-40 flex items-center justify-center bg-black/40" onClick={() => testDialog.close()}>
           <div className="bg-white dark:bg-neutral-900 rounded-lg shadow-xl p-6 max-w-md w-full mx-4" onClick={(e) => e.stopPropagation()}>
             <h2 className="text-lg font-semibold text-neutral-900 dark:text-neutral-100 mb-3">Send test event</h2>
             <p className="text-sm text-neutral-600 dark:text-neutral-400 mb-3">
@@ -354,7 +351,7 @@ export const WebhookDeliveriesPage: React.FC = () => {
               {WEBHOOK_EVENT_TYPES.map((e) => <option key={e} value={e}>{e}</option>)}
             </select>
             <div className="flex justify-end gap-2">
-              <Button variant="ghost" onClick={() => setShowTestDialog(false)}>Cancel</Button>
+              <Button variant="ghost" onClick={() => testDialog.close()}>Cancel</Button>
               <Button variant="primary" isLoading={testMutation.isPending} onClick={() => testMutation.mutate()}>
                 Send
               </Button>

frontend/src/pages/admin/accounting/AccountingInboxPage.tsx

@@ -18,6 +18,7 @@ import { EventBookingSelect } from '../../../components/admin/EventBookingSelect
 import { formatMoneyMinor } from '../../../utils/money';
 import { sortedCountryOptions } from '../../../constants/countries';
 import { useLocalizedDate } from '../../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../../hooks';
 import {
   accountingService, categoryLabel,
   type InboundDocument, type Disposition, type MarkupType, type PaymentMethod, type ExpenseCategory,
@@ -89,10 +90,11 @@ const PayModal: React.FC<{ doc: InboundDocument; onClose: () => void; onDone: ()
   const [paidAt, setPaidAt] = useState('');
   const [method, setMethod] = useState<PaymentMethod>('bank_transfer');
   const [reference, setReference] = useState(doc.paymentReference || '');
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => accountingService.markInboundPaid(doc.id, { paid: true, paidAt: paidAt || undefined, paymentMethod: method, paymentReference: reference || undefined }),
-    onSuccess: () => { toast.success(t('accounting.incoming.paidToast', 'Marked as paid.')); onDone(); },
+    successMessage: t('accounting.incoming.paidToast', 'Marked as paid.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
+    onSuccess: () => onDone(),
   });
   return (
     <div className="fixed inset-0 z-50 flex items-start justify-center overflow-y-auto bg-black/50 p-4">
@@ -205,7 +207,7 @@ const TriageModal: React.FC<{ doc: InboundDocument; categories: ExpenseCategory[
   // `pay` decides whether to also mark the supplier invoice paid in the same
   // step (#5/#1). When true we mark it paid directly (using the reference
   // entered) — no second dialog — so "Save & mark paid" actually pays.
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: async (pay: boolean) => {
       await accountingService.updateInbound(doc.id, { supplierName: supplier || null, totalAmountMinor: totalMinor, currency: currency || null, invoiceDate: invoiceDate || null, paymentReference: reference || null, note: note || null, supplierCountry: supplierCountry || null });
       await accountingService.categorizeInbound(doc.id, {
@@ -221,11 +223,9 @@ const TriageModal: React.FC<{ doc: InboundDocument; categories: ExpenseCategory[
         await accountingService.markInboundPaid(doc.id, { paid: true, paymentReference: reference || undefined });
       }
     },
-    onSuccess: (_data, pay) => {
+    successMessage: (_data, pay) => pay ? t('accounting.incoming.categorizedPaidToast', 'Categorized and marked paid.') : t('accounting.incoming.categorizedToast', 'Categorized.'),
-      toast.success(pay ? t('accounting.incoming.categorizedPaidToast', 'Categorized and marked paid.') : t('accounting.incoming.categorizedToast', 'Categorized.'));
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
-      onDone();
+    onSuccess: () => onDone(),
-    },
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
   });
 
   const rebillNeedsCustomer = disposition === 'rebill' && !customer[0];
@@ -342,10 +342,10 @@ export const AccountingInboxPage: React.FC = () => {
     onSuccess: (doc) => { toast.success(t('accounting.inbox.capturedToast', 'Document captured.')); qc.invalidateQueries({ queryKey: ['accounting-inbound'] }); if (doc.status === 'unsorted') setTriageDoc(doc); },
     onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Upload failed'),
   });
-  const unpay = useMutation({
+  const unpay = useMutationWithToast({
     mutationFn: (id: number) => accountingService.markInboundPaid(id, { paid: false }),
-    onSuccess: () => { qc.invalidateQueries({ queryKey: ['accounting-inbound'] }); },
+    invalidateKeys: [['accounting-inbound']],
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
   const billPending = useMutation({
     mutationFn: (customerAccountId: number) => accountingService.billPendingRebills(customerAccountId),

frontend/src/pages/admin/accounting/ExpensesLedgerPage.tsx

@@ -8,7 +8,7 @@
  */
 import React, { useState, useMemo } from 'react';
 import { Link } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import { toast } from 'react-toastify';
 import { X, Plus, Paperclip, Car, CalendarDays, Coins, Pencil, FileText, CheckCircle2, Circle, Lock } from 'lucide-react';
@@ -18,6 +18,7 @@ import { EventBookingSelect } from '../../../components/admin/EventBookingSelect
 import { CustomerAccountPicker, type SelectedCustomer } from '../../../components/admin/CustomerAccountPicker';
 import { formatMoneyMinor } from '../../../utils/money';
 import { useLocalizedDate } from '../../../hooks/useLocalizedDate';
+import { useMutationWithToast, useModal } from '../../../hooks';
 import {
   accountingService, categoryLabel,
   type Expense, type ExpenseKind, type ExpenseCategory, type MarkupType, type PaymentMethod,
@@ -68,12 +69,13 @@ const ExpenseFormModal: React.FC<{ categories: ExpenseCategory[]; expense?: Expe
     description: description || null,
   });
 
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => isEdit
       ? accountingService.updateExpense(expense!.id, payload(), file)
       : accountingService.createExpense(payload(), file),
-    onSuccess: () => { toast.success(isEdit ? t('accounting.ledger.updatedToast', 'Expense updated.') : t('accounting.ledger.createdToast', 'Expense added.')); onDone(); },
+    successMessage: isEdit ? t('accounting.ledger.updatedToast', 'Expense updated.') : t('accounting.ledger.createdToast', 'Expense added.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
+    onSuccess: () => onDone(),
   });
 
   const qtyLabel = kind === 'mileage' ? t('accounting.expense.km', 'Kilometres') : t('accounting.expense.days', 'Days');
@@ -143,10 +145,11 @@ const ExpensePaidModal: React.FC<{ expense: Expense; onClose: () => void; onDone
   const [paidAt, setPaidAt] = useState('');
   const [method, setMethod] = useState<PaymentMethod>('bank_transfer');
   const [reference, setReference] = useState('');
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => accountingService.markExpensePaid(expense.id, { paid: true, paidAt: paidAt || undefined, paymentMethod: method, paymentReference: reference || undefined }),
-    onSuccess: () => { toast.success(t('accounting.ledger.paidToast', 'Marked as paid.')); onDone(); },
+    successMessage: t('accounting.ledger.paidToast', 'Marked as paid.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
+    onSuccess: () => onDone(),
   });
   return (
     <div className="fixed inset-0 z-50 flex items-start justify-center bg-black/50 p-4">
@@ -182,15 +185,16 @@ const InvoiceExpenseModal: React.FC<{ expense: Expense; onClose: () => void; onD
   const [customer, setCustomer] = useState<SelectedCustomer[]>([]);
   const [markupType, setMarkupType] = useState<MarkupType>('none');
   const [markupValue, setMarkupValue] = useState<number>(NaN);
-  const save = useMutation({
+  const save = useMutationWithToast({
     mutationFn: () => accountingService.invoiceExpense(expense.id, {
       customerAccountId: customer[0]!.id,
       markupType,
       markupPercent: markupType === 'percent' && Number.isFinite(markupValue) ? markupValue : null,
       markupFlatMinor: markupType === 'flat' && Number.isFinite(markupValue) ? Math.round(markupValue * 100) : null,
     }),
-    onSuccess: () => { toast.success(t('accounting.ledger.invoicedToast', 'Added to a client invoice.')); onDone(); },
+    successMessage: t('accounting.ledger.invoicedToast', 'Added to a client invoice.'),
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
+    onSuccess: () => onDone(),
   });
   return (
     <div className="fixed inset-0 z-50 flex items-start justify-center overflow-y-auto bg-black/50 p-4">
@@ -230,15 +234,15 @@ export const ExpensesLedgerPage: React.FC = () => {
   const qc = useQueryClient();
   const { format } = useLocalizedDate();
   const [kind, setKind] = useState('');
-  const [showAdd, setShowAdd] = useState(false);
+  const addModal = useModal();
   const [editExpense, setEditExpense] = useState<Expense | null>(null);
   const [paidExpense, setPaidExpense] = useState<Expense | null>(null);
   const [invoiceExpense, setInvoiceExpense] = useState<Expense | null>(null);
 
-  const unpay = useMutation({
+  const unpay = useMutationWithToast({
     mutationFn: (id: number) => accountingService.markExpensePaid(id, { paid: false }),
-    onSuccess: () => qc.invalidateQueries({ queryKey: ['accounting-expenses'] }),
+    invalidateKeys: [['accounting-expenses']],
-    onError: (e: any) => toast.error(e?.response?.data?.error || e.message || 'Failed'),
+    errorMessage: (e: any) => e?.response?.data?.error || e.message || 'Failed',
   });
 
   const { data, isLoading } = useQuery({
@@ -262,7 +266,7 @@ export const ExpensesLedgerPage: React.FC = () => {
           <option value="">{t('accounting.ledger.allKinds', 'All types')}</option>
           {KINDS.map((k) => <option key={k} value={k}>{t(`accounting.expenseKind.${k}`, k)}</option>)}
         </select>
-        <Button className="ml-auto" onClick={() => setShowAdd(true)}><Plus className="w-4 h-4 mr-1" /> {t('accounting.ledger.addExpense', 'Add expense')}</Button>
+        <Button className="ml-auto" onClick={() => addModal.open()}><Plus className="w-4 h-4 mr-1" /> {t('accounting.ledger.addExpense', 'Add expense')}</Button>
       </div>
 
       {isLoading ? <Loading /> : items.length === 0 ? (
@@ -318,7 +322,7 @@ export const ExpensesLedgerPage: React.FC = () => {
         </div>
       )}
 
-      {showAdd && <ExpenseFormModal categories={categories ?? []} onClose={() => setShowAdd(false)} onDone={() => { setShowAdd(false); qc.invalidateQueries({ queryKey: ['accounting-expenses'] }); }} />}
+      {addModal.isOpen && <ExpenseFormModal categories={categories ?? []} onClose={() => addModal.close()} onDone={() => { addModal.close(); qc.invalidateQueries({ queryKey: ['accounting-expenses'] }); }} />}
       {editExpense && <ExpenseFormModal categories={categories ?? []} expense={editExpense} onClose={() => setEditExpense(null)} onDone={() => { setEditExpense(null); qc.invalidateQueries({ queryKey: ['accounting-expenses'] }); }} />}
       {paidExpense && <ExpensePaidModal expense={paidExpense} onClose={() => setPaidExpense(null)} onDone={() => { setPaidExpense(null); qc.invalidateQueries({ queryKey: ['accounting-expenses'] }); }} />}
       {invoiceExpense && <InvoiceExpenseModal expense={invoiceExpense} onClose={() => setInvoiceExpense(null)} onDone={() => { setInvoiceExpense(null); qc.invalidateQueries({ queryKey: ['accounting-expenses'] }); }} />}

frontend/src/pages/admin/contracts/BlockLibraryPage.tsx

@@ -27,6 +27,7 @@ import { toast } from 'react-toastify';
 import { ArrowLeft, Plus, Trash2, Save } from 'lucide-react';
 import { Button, Card, Loading } from '../../../components/common';
 import { SUPPORTED_LANGUAGES } from '../../../components/common/LanguageSelector';
+import { useMutationWithToast } from '../../../hooks';
 import {
   contractsService,
   type ContractBlock,
@@ -147,14 +148,12 @@ export const BlockLibraryPage: React.FC = () => {
     onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.blocks.updateError', 'Update failed') as string),
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (id: number) => contractsService.deleteBlock(id),
-    onSuccess: () => {
+    successMessage: t('contracts.blocks.deletedToast', 'Block deleted.') as string,
-      toast.success(t('contracts.blocks.deletedToast', 'Block deleted.') as string);
+    invalidateKeys: [['contracts', 'blocks']],
-      queryClient.invalidateQueries({ queryKey: ['contracts', 'blocks'] });
+    errorMessage: t('contracts.blocks.deleteError', 'Delete failed') as string,
-      setSelection(null);
+    onSuccess: () => setSelection(null),
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.blocks.deleteError', 'Delete failed') as string),
   });
 
   // Group blocks by section for sidebar rendering. Empty sections are

frontend/src/pages/admin/contracts/ContractDetailPage.tsx

@@ -15,7 +15,7 @@ import React, { useEffect, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useFeatureFlags } from '../../../contexts/FeatureFlagsContext';
 import { Link, useNavigate, useParams } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { toast } from 'react-toastify';
 import { billsService } from '../../../services/bills.service';
 import { quotesService } from '../../../services/quotes.service';
@@ -32,6 +32,7 @@ import {
   type ContractStatus,
 } from '../../../services/contracts.service';
 import { useLocalizedDate } from '../../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../../hooks';
 
 function statusBadgeClass(status: ContractStatus): string {
   return status === 'fully_signed'         ? 'bg-green-100 text-green-800'
@@ -90,25 +91,21 @@ export const ContractDetailPage: React.FC = () => {
     select: (res) => res?.invoices?.filter((i) => i.sourceContractId === numericId) || [],
   });
 
-  const sendMutation = useMutation({
+  const sendMutation = useMutationWithToast({
     mutationFn: () => contractsService.send(numericId as number),
-    onSuccess: () => {
+    successMessage: t('contracts.detail.sentToast', 'Contract sent.') as string,
-      toast.success(t('contracts.detail.sentToast', 'Contract sent.') as string);
+    invalidateKeys: [['contract', numericId]],
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    errorMessage: t('contracts.detail.sendError', 'Send failed') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.sendError', 'Send failed') as string),
   });
 
-  const cancelMutation = useMutation({
+  const cancelMutation = useMutationWithToast({
     mutationFn: () => contractsService.cancel(numericId as number),
-    onSuccess: () => {
+    successMessage: t('contracts.detail.cancelledToast', 'Contract cancelled.') as string,
-      toast.success(t('contracts.detail.cancelledToast', 'Contract cancelled.') as string);
+    invalidateKeys: [['contract', numericId]],
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    errorMessage: t('contracts.detail.cancelError', 'Cancel failed') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.cancelError', 'Cancel failed') as string),
   });
 
-  const countersignMutation = useMutation({
+  const countersignMutation = useMutationWithToast({
     mutationFn: () => {
       // Capture the canvas signature (if drawn) at submit time so we
       // send a fresh data URL, not a stale one from an earlier mount.
@@ -119,55 +116,45 @@ export const ContractDetailPage: React.FC = () => {
         signatureDataUrl,
       });
     },
+    successMessage: t('contracts.detail.countersignedToast', 'Counter-signed.') as string,
+    invalidateKeys: [['contract', numericId]],
+    errorMessage: t('contracts.detail.countersignError', 'Counter-sign failed') as string,
     onSuccess: () => {
-      toast.success(t('contracts.detail.countersignedToast', 'Counter-signed.') as string);
       setCountersignName('');
       countersignPadRef.current?.clear();
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
     },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.countersignError', 'Counter-sign failed') as string),
   });
 
-  const uploadMutation = useMutation({
+  const uploadMutation = useMutationWithToast({
     mutationFn: (file: File) => contractsService.uploadSignedPdf(numericId as number, file),
-    onSuccess: () => {
+    successMessage: t('contracts.detail.uploadedToast', 'Signed PDF uploaded.') as string,
-      toast.success(t('contracts.detail.uploadedToast', 'Signed PDF uploaded.') as string);
+    invalidateKeys: [['contract', numericId]],
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    errorMessage: t('contracts.detail.uploadError', 'Upload failed') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.uploadError', 'Upload failed') as string),
   });
 
-  const resendSignedMutation = useMutation({
+  const resendSignedMutation = useMutationWithToast({
     mutationFn: () => contractsService.resendSigned(numericId as number),
-    onSuccess: () => {
+    successMessage: t('contracts.detail.resentSignedToast',
-      toast.success(t('contracts.detail.resentSignedToast',
+      'Signed contract re-sent to both parties.') as string,
-        'Signed contract re-sent to both parties.') as string);
+    invalidateKeys: [['contract', numericId]],
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    errorMessage: t('contracts.detail.resendError', 'Resend failed') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error
-      || t('contracts.detail.resendError', 'Resend failed') as string),
   });
 
-  const convertToEventMutation = useMutation({
+  const convertToEventMutation = useMutationWithToast({
     mutationFn: () => contractsService.convertToEvent(numericId as number),
-    onSuccess: (result) => {
+    successMessage: (result) => result.alreadyConverted
-      toast.success(result.alreadyConverted
       ? (t('contracts.detail.alreadyEventToast', 'Already linked to an event.') as string)
-        : (t('contracts.detail.convertedToEventToast', 'Contract converted to event #{{id}}', { id: result.eventId }) as string));
+      : (t('contracts.detail.convertedToEventToast', 'Contract converted to event #{{id}}', { id: result.eventId }) as string),
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    invalidateKeys: [['contract', numericId]],
-    },
+    errorMessage: t('contracts.detail.convertError', 'Convert failed') as string,
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.convertError', 'Convert failed') as string),
   });
 
-  const convertToInvoiceMutation = useMutation({
+  const convertToInvoiceMutation = useMutationWithToast({
     mutationFn: () => contractsService.convertToInvoice(numericId as number),
-    onSuccess: (result) => {
+    successMessage: (result) => t('contracts.detail.convertedToInvoiceToast',
-      toast.success(t('contracts.detail.convertedToInvoiceToast',
+      '{{count}} invoice(s) created from this contract', { count: result.installmentsCreated }) as string,
-        '{{count}} invoice(s) created from this contract', { count: result.installmentsCreated }) as string);
+    invalidateKeys: [['contract', numericId], ['invoices']],
-      queryClient.invalidateQueries({ queryKey: ['contract', numericId] });
+    errorMessage: t('contracts.detail.convertError', 'Convert failed') as string,
-      queryClient.invalidateQueries({ queryKey: ['invoices'] });
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || t('contracts.detail.convertError', 'Convert failed') as string),
   });
 
   if (isLoading) return <Loading />;
@@ -1003,7 +990,7 @@ const RestampSignaturesCard: React.FC<RestampCardProps> = ({ contract, onSuccess
     return () => { cleanupCustomer(); cleanupAdmin(); };
   }, []);
 
-  const mutation = useMutation({
+  const mutation = useMutationWithToast({
     mutationFn: () => {
       const customerPad = customerPadRef.current;
       const adminPad = adminPadRef.current;
@@ -1017,16 +1004,16 @@ const RestampSignaturesCard: React.FC<RestampCardProps> = ({ contract, onSuccess
         adminSignatureDataUrl,
       });
     },
+    successMessage: t('contracts.detail.restampedToast',
+      'Signatures re-stamped and PDF re-rendered.') as string,
+    errorMessage: (err: any) => err?.response?.data?.error
+      || err?.message
+      || t('contracts.detail.restampError', 'Re-stamp failed') as string,
     onSuccess: () => {
-      toast.success(t('contracts.detail.restampedToast',
-        'Signatures re-stamped and PDF re-rendered.') as string);
       customerPadRef.current?.clear();
       adminPadRef.current?.clear();
       onSuccess();
     },
-    onError: (err: any) => toast.error(err?.response?.data?.error
-      || err?.message
-      || t('contracts.detail.restampError', 'Re-stamp failed') as string),
   });
 
   const missingCustomer = !contract.signedCustomerSignaturePath && contract.signedByCustomerAt;

frontend/src/pages/admin/projects/ProjectCockpitPage.tsx

@@ -24,6 +24,7 @@ import {
 } from '../../../services/projects.service';
 import { eventsService } from '../../../services/events.service';
 import { useLocalizedDate } from '../../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../../hooks';
 import { formatMoneyMinor } from '../../../utils/money';
 import { useFeatureFlags, type FeatureKey } from '../../../contexts/FeatureFlagsContext';
 
@@ -121,29 +122,24 @@ export const ProjectCockpitPage: React.FC = () => {
     enabled: projectId !== null,
   });
 
-  const renameMutation = useMutation({
+  const renameMutation = useMutationWithToast({
     mutationFn: (name: string) => projectsService.update(projectId as number, { name }),
-    onSuccess: () => {
+    successMessage: t('projects.toast.saved', 'Project saved') as string,
-      qc.invalidateQueries({ queryKey: ['project-overview', projectId] });
+    invalidateKeys: [['project-overview', projectId], ['projects']],
-      qc.invalidateQueries({ queryKey: ['projects'] });
+    errorMessage: t('projects.toast.saveFailed', 'Save failed') as string,
-      setEditName(null);
+    onSuccess: () => setEditName(null),
-      toast.success(t('projects.toast.saved', 'Project saved') as string);
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('projects.toast.saveFailed', 'Save failed') as string)),
   });
 
-  const emailActionMutation = useMutation({
+  const emailActionMutation = useMutationWithToast({
     mutationFn: ({ action, emailId }: { action: 'resend' | 'cancel' | 'retry' | 'sendNow'; emailId: number }) => {
       if (action === 'resend') return projectsService.resendEmail(emailId);
       if (action === 'cancel') return projectsService.cancelEmail(emailId);
       if (action === 'retry') return projectsService.retryEmail(emailId);
       return projectsService.sendEmailNow(emailId);
     },
-    onSuccess: () => {
+    successMessage: t('projects.toast.emailAction', 'Done') as string,
-      qc.invalidateQueries({ queryKey: ['project-overview', projectId] });
+    invalidateKeys: [['project-overview', projectId]],
-      toast.success(t('projects.toast.emailAction', 'Done') as string);
+    errorMessage: t('projects.toast.emailActionFailed', 'Action failed') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('projects.toast.emailActionFailed', 'Action failed') as string)),
   });
 
   // Event search for the "attach event" control (results exclude events

frontend/src/pages/admin/settings/CrmSettingsPage.tsx

@@ -9,13 +9,13 @@
 import React, { useEffect, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Link } from 'react-router-dom';
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { Save as SaveIcon, Workflow as WorkflowIcon } from 'lucide-react';
 import { Button, Card, Loading, Input } from '../../../components/common';
 import { settingsService } from '../../../services/settings.service';
 import { quotesService } from '../../../services/quotes.service';
 import { useFeatureFlags } from '../../../contexts/FeatureFlagsContext';
-import { toast } from 'react-toastify';
+import { useMutationWithToast } from '../../../hooks';
 
 const SETTING_KEYS = [
   'crm_quotes_pdf_attachment_enabled',
@@ -76,7 +76,6 @@ const SETTING_KEYS = [
 
 export const CrmSettingsPage: React.FC = () => {
   const { t } = useTranslation();
-  const qc = useQueryClient();
   const { flags } = useFeatureFlags();
   // Show each section only when the corresponding master flag is on —
   // configuring Skonto on quotes is pointless when quotes itself is
@@ -116,7 +115,7 @@ export const CrmSettingsPage: React.FC = () => {
   const [values, setValues] = useState<Record<string, any>>({});
   useEffect(() => { if (data) setValues(data); }, [data]);
 
-  const saveAll = useMutation({
+  const saveAll = useMutationWithToast({
     mutationFn: async () => {
       const changed: Record<string, any> = {};
       for (const key of SETTING_KEYS) {
@@ -126,11 +125,9 @@ export const CrmSettingsPage: React.FC = () => {
         await settingsService.updateSettings(changed);
       }
     },
-    onSuccess: () => {
+    successMessage: t('crmSettings.savedToast', 'CRM settings saved.'),
-      toast.success(t('crmSettings.savedToast', 'CRM settings saved.'));
+    invalidateKeys: [['settings', 'crm']],
-      qc.invalidateQueries({ queryKey: ['settings', 'crm'] });
+    errorMessage: 'Save failed',
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || 'Save failed'),
   });
 
   if (isLoading) return <Loading />;

frontend/src/pages/admin/settings/ReminderTemplatesPage.tsx

@@ -31,8 +31,7 @@
 import React, { useEffect, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Link } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { ArrowLeft, Save, AlertTriangle, Workflow as WorkflowIcon } from 'lucide-react';
 import { Button, Card, Loading, Input } from '../../../components/common';
 import { SUPPORTED_LANGUAGES } from '../../../components/common/LanguageSelector';
@@ -41,6 +40,7 @@ import { eventTypesService } from '../../../services/eventTypes.service';
 import { emailService, type EmailTemplateTranslation } from '../../../services/email.service';
 import { settingsService } from '../../../services/settings.service';
 import { useFeatureFlags } from '../../../contexts/FeatureFlagsContext';
+import { useMutationWithToast } from '../../../hooks';
 
 const TEMPLATE_KEY_DEFAULT = 'event_reminder_default';
 const TEMPLATE_KEY_PREFIX = 'event_reminder_';
@@ -60,7 +60,6 @@ interface SidebarRow {
 
 export const ReminderTemplatesPage: React.FC = () => {
   const { t } = useTranslation();
-  const queryClient = useQueryClient();
 
   // Global on/off + lead time: owned by the "Pre-event reminder" workflow when
   // the engine is live; otherwise the legacy crm_event_reminders_* settings drive
@@ -86,16 +85,14 @@ export const ReminderTemplatesPage: React.FC = () => {
     const d = Number(settings.crm_event_reminders_days_before);
     setDaysBefore(Number.isFinite(d) ? d : 2);
   }, [settings]);
-  const saveSettingsMutation = useMutation({
+  const saveSettingsMutation = useMutationWithToast({
     mutationFn: () => settingsService.updateSettings({
       crm_event_reminders_enabled: enabled,
       crm_event_reminders_days_before: daysBefore,
     }),
-    onSuccess: () => {
+    successMessage: t('reminderTemplates.settingsSaved', 'Reminder settings saved.'),
-      toast.success(t('reminderTemplates.settingsSaved', 'Reminder settings saved.'));
+    invalidateKeys: [['reminder-settings']],
-      queryClient.invalidateQueries({ queryKey: ['reminder-settings'] });
+    errorMessage: () => t('reminderTemplates.settingsSaveError', 'Could not save reminder settings.'),
-    },
-    onError: () => toast.error(t('reminderTemplates.settingsSaveError', 'Could not save reminder settings.')),
   });
 
   // ---- Event types catalog ---------------------------------------------
@@ -195,7 +192,7 @@ export const ReminderTemplatesPage: React.FC = () => {
   }, [selectedKey, selectedTemplate, defaultTemplate]);
 
   // ---- Save -------------------------------------------------------------
-  const saveMutation = useMutation({
+  const saveMutation = useMutationWithToast({
     mutationFn: async () => {
       // Only send non-empty translations so we don't clobber DB rows
       // for locales the admin hasn't touched.
@@ -220,15 +217,9 @@ export const ReminderTemplatesPage: React.FC = () => {
         });
       }
     },
-    onSuccess: () => {
+    successMessage: t('reminderTemplates.saved', 'Template saved.'),
-      toast.success(t('reminderTemplates.saved', 'Template saved.'));
+    invalidateKeys: [['email-templates'], ['email-template', selectedKey]],
-      queryClient.invalidateQueries({ queryKey: ['email-templates'] });
+    errorMessage: t('reminderTemplates.saveError', 'Could not save template.'),
-      queryClient.invalidateQueries({ queryKey: ['email-template', selectedKey] });
-    },
-    onError: (err: unknown) => {
-      const e = err as { response?: { data?: { error?: string } } };
-      toast.error(e?.response?.data?.error || t('reminderTemplates.saveError', 'Could not save template.'));
-    },
   });
 
   // Translation completeness pill for the sidebar — matches the email

frontend/src/pages/admin/settings/SettingsBusinessProfilePage.tsx

@@ -20,6 +20,7 @@ import {
 import { Button, Card, Loading, Input, CountrySelect, TimeField } from '../../../components/common';
 import { toast } from 'react-toastify';
 import { currencyOptions, normalizeCurrency } from '../../../constants/currencies';
+import { useMutationWithToast } from '../../../hooks';
 
 // Full IANA timezone list for the picker. `Intl.supportedValuesOf` is ES2022
 // (all current browsers); fall back to a small CH/LI-relevant set on the rare
@@ -35,7 +36,6 @@ const IANA_TIMEZONES: string[] = (() => {
 
 export const SettingsBusinessProfilePage: React.FC = () => {
   const { t } = useTranslation();
-  const qc = useQueryClient();
   const { data, isLoading } = useQuery({
     queryKey: ['business-profile'],
     queryFn: () => businessProfileService.get(),
@@ -44,7 +44,7 @@ export const SettingsBusinessProfilePage: React.FC = () => {
   const [profile, setProfile] = useState<BusinessProfile | null>(null);
   useEffect(() => { if (data?.profile) setProfile(data.profile); }, [data]);
 
-  const saveProfile = useMutation({
+  const saveProfile = useMutationWithToast({
     // vatLabel + defaultHourlyRateMinor now live on Settings → Accounting, and
     // vatRateDefault is retired (the rates are the Accounting VAT codes). Strip
     // them from this save so an open Business-profile page can't clobber an edit
@@ -55,11 +55,9 @@ export const SettingsBusinessProfilePage: React.FC = () => {
       void vatLabel; void defaultHourlyRateMinor; void vatRateDefault;
       return businessProfileService.update(rest);
     },
-    onSuccess: () => {
+    successMessage: t('businessProfile.savedToast', 'Business profile saved.'),
-      toast.success(t('businessProfile.savedToast', 'Business profile saved.'));
+    invalidateKeys: [['business-profile']],
-      qc.invalidateQueries({ queryKey: ['business-profile'] });
+    errorMessage: 'Save failed',
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || 'Save failed'),
   });
 
   if (isLoading || !profile) return <Loading />;
@@ -614,24 +612,20 @@ const BankAccountsSection: React.FC<BankAccountsSectionProps> = ({ accounts }) =
   };
   const closeForm = () => { setOpenForm(null); setDraft(EMPTY_DRAFT); };
 
-  const create = useMutation({
+  const create = useMutationWithToast({
     mutationFn: () => businessProfileService.createBankAccount(draft),
-    onSuccess: () => {
+    successMessage: t('businessProfile.bankCreatedToast', 'Bank account added.'),
-      toast.success(t('businessProfile.bankCreatedToast', 'Bank account added.'));
+    invalidateKeys: [['business-profile']],
-      qc.invalidateQueries({ queryKey: ['business-profile'] });
+    errorMessage: 'Failed',
-      closeForm();
+    onSuccess: () => closeForm(),
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || 'Failed'),
   });
 
-  const update = useMutation({
+  const update = useMutationWithToast({
     mutationFn: (id: number) => businessProfileService.updateBankAccount(id, draft),
-    onSuccess: () => {
+    successMessage: t('businessProfile.bankUpdatedToast', 'Bank account updated.'),
-      toast.success(t('businessProfile.bankUpdatedToast', 'Bank account updated.'));
+    invalidateKeys: [['business-profile']],
-      qc.invalidateQueries({ queryKey: ['business-profile'] });
+    errorMessage: 'Failed',
-      closeForm();
+    onSuccess: () => closeForm(),
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || 'Failed'),
   });
 
   const setDefault = useMutation({

frontend/src/pages/admin/workflows/WorkflowApprovalsPage.tsx

@@ -7,17 +7,16 @@
 import React from 'react';
 import { useTranslation } from 'react-i18next';
 import { useNavigate } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
-import { toast } from 'react-toastify';
 import { ArrowLeft, Check, X } from 'lucide-react';
 import { Button, Card, Loading } from '../../../components/common';
 import { workflowsService, type WorkflowApproval } from '../../../services/workflows.service';
 import { useLocalizedDate } from '../../../hooks/useLocalizedDate';
+import { useMutationWithToast } from '../../../hooks';
 
 export const WorkflowApprovalsPage: React.FC = () => {
   const { t } = useTranslation();
   const navigate = useNavigate();
-  const qc = useQueryClient();
   const { formatDateTime } = useLocalizedDate();
 
   const { data: approvals, isLoading } = useQuery({
@@ -25,13 +24,11 @@ export const WorkflowApprovalsPage: React.FC = () => {
     queryFn: () => workflowsService.approvals(),
   });
 
-  const actMutation = useMutation({
+  const actMutation = useMutationWithToast({
     mutationFn: ({ id, action }: { id: number; action: 'confirm' | 'deny' }) => workflowsService.actApproval(id, action),
-    onSuccess: () => {
+    successMessage: t('workflows.approvals.recorded', 'Response recorded') as string,
-      qc.invalidateQueries({ queryKey: ['workflow-approvals'] });
+    invalidateKeys: [['workflow-approvals']],
-      toast.success(t('workflows.approvals.recorded', 'Response recorded') as string);
+    errorMessage: t('common.error', 'Something went wrong') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('common.error', 'Something went wrong') as string)),
   });
 
   const promptOf = (a: WorkflowApproval) => (a.payload && (a.payload.prompt as string)) || t('workflows.approvals.defaultPrompt', 'A workflow needs your confirmation.');

frontend/src/pages/admin/workflows/WorkflowEditorPage.tsx

@@ -10,7 +10,7 @@
 import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useNavigate, useParams } from 'react-router-dom';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
 import { toast } from 'react-toastify';
 import {
   ReactFlow, Background, Controls, MiniMap, addEdge, useNodesState, useEdgesState,
@@ -22,6 +22,7 @@ import { ArrowLeft, Save, Trash2, Wand2, Code } from 'lucide-react';
 import { Button, Loading } from '../../../components/common';
 import { api } from '../../../config/api';
 import { useAdminDarkMode } from '../../../contexts/AdminDarkModeContext';
+import { useMutationWithToast } from '../../../hooks';
 import { workflowsService, type WorkflowNodeType } from '../../../services/workflows.service';
 import { NodeConfigPanel } from './NodeConfigPanel';
 
@@ -117,7 +118,6 @@ function layoutGraph(nodes: Node[], edges: Edge[]): Node[] {
 export const WorkflowEditorPage: React.FC = () => {
   const { t } = useTranslation();
   const navigate = useNavigate();
-  const qc = useQueryClient();
   const { isDark } = useAdminDarkMode();
   const { id } = useParams<{ id: string }>();
   const workflowId = Number(id);
@@ -245,7 +245,7 @@ export const WorkflowEditorPage: React.FC = () => {
     setSelectedId(null);
   };
 
-  const saveMutation = useMutation({
+  const saveMutation = useMutationWithToast({
     mutationFn: () => workflowsService.update(workflowId, {
       name: name.trim() || 'Untitled',
       trigger_type: triggerType,
@@ -257,12 +257,9 @@ export const WorkflowEditorPage: React.FC = () => {
       })),
       edges: edges.map((e) => ({ from_node: e.source, from_handle: e.sourceHandle || null, to_node: e.target })),
     }),
-    onSuccess: () => {
+    successMessage: t('workflows.editor.saved', 'Workflow saved') as string,
-      qc.invalidateQueries({ queryKey: ['workflow', workflowId] });
+    invalidateKeys: [['workflow', workflowId], ['workflows']],
-      qc.invalidateQueries({ queryKey: ['workflows'] });
+    errorMessage: t('workflows.editor.saveFailed', 'Could not save') as string,
-      toast.success(t('workflows.editor.saved', 'Workflow saved') as string);
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('workflows.editor.saveFailed', 'Could not save') as string)),
   });
 
   if (isLoading) return <div className="p-10"><Loading /></div>;

frontend/src/pages/admin/workflows/WorkflowsListPage.tsx

@@ -11,6 +11,7 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { toast } from 'react-toastify';
 import { Plus, Workflow as WorkflowIcon, Inbox, Trash2, Pencil, FlaskConical } from 'lucide-react';
 import { Button, Card, Loading } from '../../../components/common';
+import { useMutationWithToast } from '../../../hooks';
 import { workflowsService, type WorkflowSummary, type WorkflowSavePayload, type WorkflowTestResult } from '../../../services/workflows.service';
 
 const NEW_WORKFLOW: WorkflowSavePayload = {
@@ -55,19 +56,17 @@ export const WorkflowsListPage: React.FC = () => {
     onError: (err: any) => toast.error(err?.response?.data?.error || (t('workflows.test.failed', 'Test run failed') as string)),
   });
 
-  const toggleMutation = useMutation({
+  const toggleMutation = useMutationWithToast({
     mutationFn: ({ id, enabled }: { id: number; enabled: boolean }) => workflowsService.setEnabled(id, enabled),
-    onSuccess: () => qc.invalidateQueries({ queryKey: ['workflows'] }),
+    invalidateKeys: [['workflows']],
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('common.error', 'Something went wrong') as string)),
+    errorMessage: t('common.error', 'Something went wrong') as string,
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useMutationWithToast({
     mutationFn: (id: number) => workflowsService.remove(id),
-    onSuccess: () => {
+    successMessage: t('workflows.toast.deleted', 'Workflow deleted') as string,
-      qc.invalidateQueries({ queryKey: ['workflows'] });
+    invalidateKeys: [['workflows']],
-      toast.success(t('workflows.toast.deleted', 'Workflow deleted') as string);
+    errorMessage: t('workflows.toast.deleteFailed', 'Could not delete workflow') as string,
-    },
-    onError: (err: any) => toast.error(err?.response?.data?.error || (t('workflows.toast.deleteFailed', 'Could not delete workflow') as string)),
   });
 
   const isEnabled = (w: WorkflowSummary) => w.enabled === true || w.enabled === 1;