diff --git a/src/components/settings/NotificationsTab.tsx b/src/components/settings/NotificationsTab.tsx
index fee05aa2..ae3b171d 100644
--- a/src/components/settings/NotificationsTab.tsx
+++ b/src/components/settings/NotificationsTab.tsx
@@ -8,48 +8,32 @@ import { Button } from "@/components/ui/button";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { Separator } from "@/components/ui/separator";
 import { Badge } from "@/components/ui/badge";
-import { toast } from "sonner";
+import { Skeleton } from "@/components/ui/skeleton";
+import { handleError, handleSuccess, handleInfo } from "@/lib/errorHandler";
+import { logger } from "@/lib/logger";
 import { notificationService } from "@/lib/notificationService";
-
-interface ChannelPreferences {
-  in_app: boolean;
-  email: boolean;
-  push: boolean;
-}
-
-interface WorkflowPreferences {
-  [workflowId: string]: boolean;
-}
-
-interface FrequencySettings {
-  digest: 'realtime' | 'hourly' | 'daily' | 'weekly';
-  max_per_hour: number;
-}
-
-interface NotificationTemplate {
-  id: string;
-  workflow_id: string;
-  name: string;
-  description: string;
-  category: string;
-  is_active: boolean;
-}
+import type {
+  NotificationPreferences,
+  NotificationTemplate,
+  ChannelPreferences,
+  WorkflowPreferences,
+  FrequencySettings
+} from "@/types/notifications";
+import { DEFAULT_NOTIFICATION_PREFERENCES } from "@/lib/notificationValidation";
 
 export function NotificationsTab() {
   const { user } = useAuth();
   const { isEnabled: isNovuEnabled, isLoading: isNovuLoading } = usePublicNovuSettings();
   const [loading, setLoading] = useState(true);
+  const [saving, setSaving] = useState(false);
   const [templates, setTemplates] = useState<NotificationTemplate[]>([]);
-  const [channelPreferences, setChannelPreferences] = useState<ChannelPreferences>({
-    in_app: true,
-    email: true,
-    push: false,
-  });
+  const [channelPreferences, setChannelPreferences] = useState<ChannelPreferences>(
+    DEFAULT_NOTIFICATION_PREFERENCES.channelPreferences
+  );
   const [workflowPreferences, setWorkflowPreferences] = useState<WorkflowPreferences>({});
-  const [frequencySettings, setFrequencySettings] = useState<FrequencySettings>({
-    digest: 'daily',
-    max_per_hour: 10,
-  });
+  const [frequencySettings, setFrequencySettings] = useState<FrequencySettings>(
+    DEFAULT_NOTIFICATION_PREFERENCES.frequencySettings
+  );
 
   useEffect(() => {
     if (user) {
@@ -65,71 +49,109 @@ export function NotificationsTab() {
       const preferences = await notificationService.getPreferences(user.id);
       
       if (preferences) {
-        const { sms, ...channelPrefs } = preferences.channelPreferences;
-        setChannelPreferences(channelPrefs);
+        setChannelPreferences(preferences.channelPreferences);
         setWorkflowPreferences(preferences.workflowPreferences);
         setFrequencySettings(preferences.frequencySettings);
       }
+
+      logger.info('Notification preferences loaded', {
+        action: 'load_notification_preferences',
+        userId: user.id
+      });
     } catch (error) {
-      console.error('Error loading preferences:', error);
-      toast.error("Failed to load notification preferences");
+      logger.error('Failed to load notification preferences', {
+        action: 'load_notification_preferences',
+        userId: user.id,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      handleError(error, {
+        action: 'Load notification preferences',
+        userId: user.id
+      });
     } finally {
       setLoading(false);
     }
   };
 
   const loadTemplates = async () => {
+    if (!user) return;
+
     try {
       const templateData = await notificationService.getTemplates();
       setTemplates(templateData);
       
-      // Initialize workflow preferences if not set
+      // Initialize workflow preferences for new templates
       const initialPrefs: WorkflowPreferences = {};
       templateData.forEach((template) => {
         if (!(template.workflow_id in workflowPreferences)) {
           initialPrefs[template.workflow_id] = true;
         }
       });
+
       if (Object.keys(initialPrefs).length > 0) {
         setWorkflowPreferences((prev) => ({ ...prev, ...initialPrefs }));
       }
+
+      logger.info('Notification templates loaded', {
+        action: 'load_notification_templates',
+        userId: user.id,
+        count: templateData.length
+      });
     } catch (error) {
-      console.error('Error loading templates:', error);
+      logger.error('Failed to load notification templates', {
+        action: 'load_notification_templates',
+        userId: user.id,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      handleError(error, {
+        action: 'Load notification templates',
+        userId: user.id
+      });
     }
   };
 
   const savePreferences = async () => {
     if (!user) return;
 
-    setLoading(true);
+    setSaving(true);
+
     try {
-      const result = await notificationService.updatePreferences(user.id, {
-        channelPreferences: {
-          ...channelPreferences,
-          sms: false, // SMS not supported in UI
-        },
+      const preferences: NotificationPreferences = {
+        channelPreferences,
         workflowPreferences,
-        frequencySettings,
+        frequencySettings
+      };
+
+      const result = await notificationService.updatePreferences(user.id, preferences);
+
+      if (!result.success) {
+        throw new Error(result.error || 'Failed to save notification preferences');
+      }
+
+      logger.info('Notification preferences saved', {
+        action: 'save_notification_preferences',
+        userId: user.id
       });
 
-      if (result.success) {
-        toast.success("Notification preferences saved successfully");
-        
-        // Also update Novu subscriber profile to sync channel preferences
-        if (notificationService.isEnabled()) {
-          await notificationService.updateSubscriber({
-            subscriberId: user.id,
-            email: user.email,
-          });
-        }
-      } else {
-        throw new Error(result.error || 'Failed to save preferences');
-      }
-    } catch (error: any) {
-      console.error('Error saving preferences:', error);
-      toast.error(error.message || "Failed to save notification preferences");
+      handleSuccess(
+        'Notification preferences saved',
+        'Your notification settings have been updated successfully.'
+      );
+    } catch (error) {
+      logger.error('Error saving notification preferences', {
+        action: 'save_notification_preferences',
+        userId: user.id,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      handleError(error, {
+        action: 'Save notification preferences',
+        userId: user.id
+      });
     } finally {
-      setLoading(false);
+      setSaving(false);
     }
   };
 
@@ -143,21 +165,36 @@ export function NotificationsTab() {
 
   const requestPushPermission = async () => {
     if (!('Notification' in window)) {
-      toast.error("This browser doesn't support push notifications");
+      handleInfo(
+        'Push notifications not supported',
+        'Your browser does not support push notifications.'
+      );
       return;
     }
 
     try {
       const permission = await Notification.requestPermission();
+      
       if (permission === 'granted') {
         updateChannelPreference('push', true);
-        toast.success("Push notifications enabled");
+        handleSuccess('Push notifications enabled', 'You will now receive push notifications.');
       } else {
-        toast.error("Push notification permission denied");
+        handleInfo(
+          'Permission denied',
+          'Push notifications were not enabled. You can change this in your browser settings.'
+        );
       }
     } catch (error) {
-      console.error('Error requesting push permission:', error);
-      toast.error("Failed to enable push notifications");
+      logger.error('Error requesting push permission', {
+        action: 'request_push_permission',
+        userId: user?.id,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      handleError(error, {
+        action: 'Enable push notifications',
+        userId: user?.id
+      });
     }
   };
 
@@ -169,24 +206,38 @@ export function NotificationsTab() {
     return acc;
   }, {} as Record<string, NotificationTemplate[]>);
 
-  return (
-    <div className="space-y-6">
-      {isNovuLoading ? (
+  if (loading || isNovuLoading) {
+    return (
+      <div className="space-y-6">
         <Card>
           <CardHeader>
-            <CardDescription>Loading notification settings...</CardDescription>
+            <Skeleton className="h-6 w-48" />
+            <Skeleton className="h-4 w-full max-w-md" />
           </CardHeader>
+          <CardContent className="space-y-4">
+            <Skeleton className="h-12 w-full" />
+            <Skeleton className="h-12 w-full" />
+            <Skeleton className="h-12 w-full" />
+          </CardContent>
         </Card>
-      ) : !isNovuEnabled ? (
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-6">
+      {!isNovuEnabled && (
         <Card className="border-yellow-500/50 bg-yellow-500/10">
           <CardHeader>
-            <CardTitle className="text-yellow-600 dark:text-yellow-400">Novu Not Configured</CardTitle>
+            <CardTitle className="text-yellow-600 dark:text-yellow-400">
+              Novu Not Configured
+            </CardTitle>
             <CardDescription>
-              Novu notifications are not configured. Contact an administrator to configure the Novu Application Identifier in admin settings.
+              Notifications are not fully configured. Contact an administrator to enable Novu integration.
             </CardDescription>
           </CardHeader>
         </Card>
-      ) : null}
+      )}
 
       <Card>
         <CardHeader>
@@ -247,7 +298,6 @@ export function NotificationsTab() {
               }}
             />
           </div>
-
         </CardContent>
       </Card>
 
@@ -263,7 +313,7 @@ export function NotificationsTab() {
             <Label>Digest Frequency</Label>
             <Select
               value={frequencySettings.digest}
-              onValueChange={(value: any) => 
+              onValueChange={(value: 'realtime' | 'hourly' | 'daily' | 'weekly') => 
                 setFrequencySettings((prev) => ({ ...prev, digest: value }))
               }
             >
@@ -325,9 +375,11 @@ export function NotificationsTab() {
                 <div className="flex items-center justify-between">
                   <div className="space-y-0.5">
                     <Label>{template.name}</Label>
-                    <p className="text-sm text-muted-foreground">
-                      {template.description}
-                    </p>
+                    {template.description && (
+                      <p className="text-sm text-muted-foreground">
+                        {template.description}
+                      </p>
+                    )}
                   </div>
                   <Switch
                     checked={workflowPreferences[template.workflow_id] ?? true}
@@ -345,9 +397,9 @@ export function NotificationsTab() {
       <Button 
         onClick={savePreferences}
         className="w-full"
-        disabled={loading}
+        disabled={saving}
       >
-        {loading ? 'Saving...' : 'Save Notification Preferences'}
+        {saving ? 'Saving...' : 'Save Notification Preferences'}
       </Button>
     </div>
   );
diff --git a/src/lib/notificationService.ts b/src/lib/notificationService.ts
index 4d91113f..f974403a 100644
--- a/src/lib/notificationService.ts
+++ b/src/lib/notificationService.ts
@@ -1,95 +1,38 @@
 import { supabase } from "@/integrations/supabase/client";
-
-export interface NotificationPayload {
-  workflowId: string;
-  subscriberId: string;
-  payload: Record<string, any>;
-  overrides?: Record<string, any>;
-}
-
-export interface SubscriberData {
-  subscriberId: string;
-  email?: string;
-  firstName?: string;
-  lastName?: string;
-  phone?: string;
-  avatar?: string;
-  data?: Record<string, any>;
-}
-
-export interface NotificationPreferences {
-  channelPreferences: {
-    in_app: boolean;
-    email: boolean;
-    push: boolean;
-    sms: boolean;
-  };
-  workflowPreferences: Record<string, boolean>;
-  frequencySettings: {
-    digest: 'realtime' | 'hourly' | 'daily' | 'weekly';
-    max_per_hour: number;
-  };
-}
+import { logger } from "@/lib/logger";
+import { AppError } from "@/lib/errorHandler";
+import { z } from "zod";
+import type {
+  NotificationPayload,
+  SubscriberData,
+  NotificationPreferences,
+  NotificationTemplate
+} from "@/types/notifications";
+import {
+  notificationPreferencesSchema,
+  subscriberDataSchema,
+  DEFAULT_NOTIFICATION_PREFERENCES
+} from "@/lib/notificationValidation";
 
 class NotificationService {
-  private readonly isNovuEnabled: boolean;
-
-  constructor() {
-    this.isNovuEnabled = !!import.meta.env.VITE_NOVU_APPLICATION_IDENTIFIER;
-  }
-
-  private extractErrorMessage(error: unknown): string {
-    if (error instanceof Error) {
-      return error.message;
-    }
-    if (error && typeof error === 'object' && 'message' in error && typeof error.message === 'string') {
-      return error.message;
-    }
-    return 'An unexpected error occurred';
-  }
-
   /**
-   * Create or update a Novu subscriber
+   * Check if Novu is enabled by checking admin settings
    */
-  async createSubscriber(subscriberData: SubscriberData): Promise<{ success: boolean; error?: string }> {
-    if (!this.isNovuEnabled) {
-      console.warn('Novu is not configured. Skipping subscriber creation.');
-      return { success: false, error: 'Novu not configured' };
-    }
-
+  async isNovuEnabled(): Promise<boolean> {
     try {
-      const { data, error } = await supabase.functions.invoke('create-novu-subscriber', {
-        body: subscriberData,
+      const { data } = await supabase
+        .from('admin_settings')
+        .select('setting_value')
+        .eq('setting_key', 'novu.application_identifier')
+        .maybeSingle();
+      
+      return !!data?.setting_value;
+    } catch (error) {
+      logger.error('Failed to check Novu status', {
+        action: 'check_novu_status',
+        error: error instanceof Error ? error.message : String(error)
       });
-
-      if (error) {
-        console.error('Edge function error creating Novu subscriber:', error);
-        throw error;
-      }
-
-      if (!data || !data.subscriberId) {
-        const errorMsg = 'Invalid response from create-novu-subscriber function';
-        console.error(errorMsg, { data });
-        return { success: false, error: errorMsg };
-      }
-
-      const { error: dbError } = await supabase
-        .from('user_notification_preferences')
-        .upsert({
-          user_id: subscriberData.subscriberId,
-          novu_subscriber_id: data.subscriberId,
-        });
-
-      if (dbError) {
-        console.error('Database error storing subscriber preferences:', dbError);
-        throw dbError;
-      }
-
-      console.log('Novu subscriber created successfully:', data.subscriberId);
-      return { success: true };
-    } catch (error: unknown) {
-      console.error('Error creating Novu subscriber:', error);
-      return { success: false, error: this.extractErrorMessage(error) };
+      return false;
     }
   }
 
@@ -97,137 +40,235 @@ class NotificationService {
    * Update an existing Novu subscriber's profile information
    */
   async updateSubscriber(subscriberData: SubscriberData): Promise<{ success: boolean; error?: string }> {
-    if (!this.isNovuEnabled) {
-      console.warn('Novu is not configured. Skipping subscriber update.');
-      return { success: false, error: 'Novu not configured' };
-    }
-
     try {
+      // Validate input
+      const validated = subscriberDataSchema.parse(subscriberData);
+      
+      const novuEnabled = await this.isNovuEnabled();
+      if (!novuEnabled) {
+        logger.warn('Novu not configured, skipping subscriber update', {
+          action: 'update_novu_subscriber',
+          userId: validated.subscriberId
+        });
+        return { success: false, error: 'Novu not configured' };
+      }
+
       const { data, error } = await supabase.functions.invoke('update-novu-subscriber', {
-        body: subscriberData,
+        body: validated,
       });
 
       if (error) {
-        console.error('Edge function error updating Novu subscriber:', error);
-        throw error;
+        logger.error('Edge function error updating Novu subscriber', {
+          action: 'update_novu_subscriber',
+          userId: validated.subscriberId,
+          error: error.message
+        });
+        throw new AppError(
+          'Failed to update notification subscriber',
+          'NOTIFICATION_ERROR',
+          error.message
+        );
       }
 
-      console.log('Novu subscriber updated successfully:', subscriberData.subscriberId);
+      logger.info('Novu subscriber updated successfully', {
+        action: 'update_novu_subscriber',
+        userId: validated.subscriberId
+      });
+
       return { success: true };
-    } catch (error: unknown) {
-      console.error('Error updating Novu subscriber:', error);
-      return { success: false, error: this.extractErrorMessage(error) };
+    } catch (error) {
+      logger.error('Error in updateSubscriber', {
+        action: 'update_novu_subscriber',
+        userId: subscriberData.subscriberId,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      return {
+        success: false,
+        error: error instanceof AppError ? error.message : 'Failed to update subscriber'
+      };
     }
   }
 
   /**
-   * Update subscriber preferences in Novu
+   * Create or update a Novu subscriber
+   */
+  async createSubscriber(subscriberData: SubscriberData): Promise<{ success: boolean; error?: string }> {
+    try {
+      // Validate input
+      const validated = subscriberDataSchema.parse(subscriberData);
+      
+      const novuEnabled = await this.isNovuEnabled();
+      if (!novuEnabled) {
+        logger.warn('Novu not configured, skipping subscriber creation', {
+          action: 'create_novu_subscriber',
+          userId: validated.subscriberId
+        });
+        return { success: false, error: 'Novu not configured' };
+      }
+
+      const { data, error } = await supabase.functions.invoke('create-novu-subscriber', {
+        body: validated,
+      });
+
+      if (error) {
+        logger.error('Edge function error creating Novu subscriber', {
+          action: 'create_novu_subscriber',
+          userId: validated.subscriberId,
+          error: error.message
+        });
+        throw new AppError(
+          'Failed to create notification subscriber',
+          'NOTIFICATION_ERROR',
+          error.message
+        );
+      }
+
+      if (!data?.subscriberId) {
+        throw new AppError(
+          'Invalid response from notification service',
+          'NOTIFICATION_ERROR'
+        );
+      }
+
+      // Store subscriber ID in database
+      const { error: dbError } = await supabase
+        .from('user_notification_preferences')
+        .upsert({
+          user_id: validated.subscriberId,
+          novu_subscriber_id: data.subscriberId,
+        });
+
+      if (dbError) {
+        logger.error('Failed to store subscriber preferences', {
+          action: 'store_subscriber_preferences',
+          userId: validated.subscriberId,
+          error: dbError.message,
+          errorCode: dbError.code
+        });
+        throw dbError;
+      }
+
+      logger.info('Novu subscriber created successfully', {
+        action: 'create_novu_subscriber',
+        userId: validated.subscriberId
+      });
+
+      return { success: true };
+    } catch (error) {
+      logger.error('Error in createSubscriber', {
+        action: 'create_novu_subscriber',
+        userId: subscriberData.subscriberId,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      return {
+        success: false,
+        error: error instanceof AppError ? error.message : 'Failed to create subscriber'
+      };
+    }
+  }
+
+  /**
+   * Update notification preferences with validation and audit logging
    */
   async updatePreferences(
     userId: string,
     preferences: NotificationPreferences
   ): Promise<{ success: boolean; error?: string }> {
-    if (!this.isNovuEnabled) {
-      try {
-        const { error } = await supabase
-          .from('user_notification_preferences')
-          .upsert({
-            user_id: userId,
-            channel_preferences: preferences.channelPreferences,
-            workflow_preferences: preferences.workflowPreferences,
-            frequency_settings: preferences.frequencySettings,
-          });
-
-        if (error) {
-          console.error('Database error saving preferences (Novu disabled):', error);
-          throw error;
-        }
-
-        console.log('Preferences saved to local database:', userId);
-        return { success: true };
-      } catch (error: unknown) {
-        console.error('Error saving preferences to local database:', error);
-        return { success: false, error: this.extractErrorMessage(error) };
-      }
-    }
-
     try {
-      const { error } = await supabase.functions.invoke('update-novu-preferences', {
-        body: {
-          userId,
-          preferences,
-        },
-      });
+      // Validate preferences
+      const validated = notificationPreferencesSchema.parse(preferences);
 
-      if (error) {
-        console.error('Edge function error updating Novu preferences:', error);
-        throw error;
+      // Get previous preferences for audit log
+      const { data: previousPrefs } = await supabase
+        .from('user_notification_preferences')
+        .select('channel_preferences, workflow_preferences, frequency_settings')
+        .eq('user_id', userId)
+        .maybeSingle();
+
+      const novuEnabled = await this.isNovuEnabled();
+
+      // Update Novu preferences if enabled
+      if (novuEnabled) {
+        const { error: novuError } = await supabase.functions.invoke('update-novu-preferences', {
+          body: {
+            userId,
+            preferences: validated,
+          },
+        });
+
+        if (novuError) {
+          logger.error('Failed to update Novu preferences', {
+            action: 'update_novu_preferences',
+            userId,
+            error: novuError.message
+          });
+          throw novuError;
+        }
       }
 
+      // Update local database
       const { error: dbError } = await supabase
         .from('user_notification_preferences')
         .upsert({
           user_id: userId,
-          channel_preferences: preferences.channelPreferences,
-          workflow_preferences: preferences.workflowPreferences,
-          frequency_settings: preferences.frequencySettings,
+          channel_preferences: validated.channelPreferences,
+          workflow_preferences: validated.workflowPreferences,
+          frequency_settings: validated.frequencySettings,
         });
 
       if (dbError) {
-        console.error('Database error saving preferences locally:', dbError);
+        logger.error('Failed to save notification preferences', {
+          action: 'save_notification_preferences',
+          userId,
+          error: dbError.message,
+          errorCode: dbError.code
+        });
         throw dbError;
       }
 
-      console.log('Preferences updated successfully:', userId);
+      // Create audit log entry
+      await supabase.from('profile_audit_log').insert([{
+        user_id: userId,
+        changed_by: userId,
+        action: 'notification_preferences_updated',
+        changes: {
+          previous: previousPrefs || null,
+          updated: validated,
+          timestamp: new Date().toISOString()
+        } as any
+      }]);
+
+      logger.info('Notification preferences updated', {
+        action: 'update_notification_preferences',
+        userId
+      });
+
       return { success: true };
-    } catch (error: unknown) {
-      console.error('Error updating preferences:', error);
-      return { success: false, error: this.extractErrorMessage(error) };
+    } catch (error) {
+      logger.error('Error updating notification preferences', {
+        action: 'update_notification_preferences',
+        userId,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      if (error instanceof z.ZodError) {
+        return {
+          success: false,
+          error: `Invalid preferences: ${error.issues.map(i => i.message).join(', ')}`
+        };
+      }
+
+      return {
+        success: false,
+        error: 'Failed to update notification preferences'
+      };
     }
   }
 
   /**
-   * Trigger a notification workflow
-   */
-  async trigger(payload: NotificationPayload): Promise<{ success: boolean; transactionId?: string; error?: string }> {
-    if (!this.isNovuEnabled) {
-      console.warn('Novu is not configured. Notification not sent.');
-      return { success: false, error: 'Novu not configured' };
-    }
-
-    try {
-      const { data, error } = await supabase.functions.invoke('trigger-notification', {
-        body: payload,
-      });
-
-      if (error) {
-        console.error('Edge function error triggering notification:', error);
-        throw error;
-      }
-
-      if (!data || !data.transactionId) {
-        const errorMsg = 'Invalid response from trigger-notification function';
-        console.error(errorMsg, { data });
-        return { success: false, error: errorMsg };
-      }
-
-      await this.logNotification({
-        userId: payload.subscriberId,
-        workflowId: payload.workflowId,
-        transactionId: data.transactionId,
-        payload: payload.payload,
-      });
-
-      console.log('Notification triggered successfully:', data.transactionId);
-      return { success: true, transactionId: data.transactionId };
-    } catch (error: unknown) {
-      console.error('Error triggering notification:', error);
-      return { success: false, error: this.extractErrorMessage(error) };
-    }
-  }
-
-  /**
-   * Get user's notification preferences
+   * Get user's notification preferences with proper typing
    */
   async getPreferences(userId: string): Promise<NotificationPreferences | null> {
     try {
@@ -235,37 +276,38 @@ class NotificationService {
         .from('user_notification_preferences')
         .select('channel_preferences, workflow_preferences, frequency_settings')
         .eq('user_id', userId)
-        .single();
+        .maybeSingle();
 
       if (error && error.code !== 'PGRST116') {
-        console.error('Database error fetching preferences:', error);
+        logger.error('Failed to fetch notification preferences', {
+          action: 'fetch_notification_preferences',
+          userId,
+          error: error.message,
+          errorCode: error.code
+        });
         throw error;
       }
 
       if (!data) {
-        console.log('No preferences found for user, returning defaults:', userId);
-        return {
-          channelPreferences: {
-            in_app: true,
-            email: true,
-            push: false,
-            sms: false,
-          },
-          workflowPreferences: {},
-          frequencySettings: {
-            digest: 'daily',
-            max_per_hour: 10,
-          },
-        };
+        logger.info('No preferences found, returning defaults', {
+          action: 'fetch_notification_preferences',
+          userId
+        });
+        return DEFAULT_NOTIFICATION_PREFERENCES;
       }
 
-      return {
-        channelPreferences: data.channel_preferences as any,
-        workflowPreferences: data.workflow_preferences as any,
-        frequencySettings: data.frequency_settings as any,
-      };
-    } catch (error: unknown) {
-      console.error('Error fetching notification preferences for user:', userId, error);
+      // Validate the data from database
+      return notificationPreferencesSchema.parse({
+        channelPreferences: data.channel_preferences,
+        workflowPreferences: data.workflow_preferences,
+        frequencySettings: data.frequency_settings
+      });
+    } catch (error) {
+      logger.error('Error fetching notification preferences', {
+        action: 'fetch_notification_preferences',
+        userId,
+        error: error instanceof Error ? error.message : String(error)
+      });
       return null;
     }
   }
@@ -273,7 +315,7 @@ class NotificationService {
   /**
    * Get notification templates
    */
-  async getTemplates(): Promise<any[]> {
+  async getTemplates(): Promise<NotificationTemplate[]> {
     try {
       const { data, error } = await supabase
         .from('notification_templates')
@@ -282,90 +324,117 @@ class NotificationService {
         .order('category', { ascending: true });
 
       if (error) {
-        console.error('Database error fetching notification templates:', error);
+        logger.error('Failed to fetch notification templates', {
+          action: 'fetch_notification_templates',
+          error: error.message,
+          errorCode: error.code
+        });
         throw error;
       }
 
       return data || [];
-    } catch (error: unknown) {
-      console.error('Error fetching notification templates:', error);
+    } catch (error) {
+      logger.error('Error fetching notification templates', {
+        action: 'fetch_notification_templates',
+        error: error instanceof Error ? error.message : String(error)
+      });
       return [];
     }
   }
 
   /**
-   * Log notification in database
+   * Trigger a notification workflow
    */
-  private async logNotification(log: {
-    userId: string;
-    workflowId: string;
-    transactionId: string;
-    payload: Record<string, any>;
-  }): Promise<void> {
+  async trigger(payload: NotificationPayload): Promise<{ success: boolean; error?: string }> {
     try {
-      // Get template ID from workflow ID
-      const { data: template } = await supabase
-        .from('notification_templates')
-        .select('id')
-        .eq('workflow_id', log.workflowId)
-        .single();
-
-      const { error: logError } = await supabase.from('notification_logs').insert({
-        user_id: log.userId,
-        template_id: template?.id,
-        novu_transaction_id: log.transactionId,
-        channel: 'multi',
-        status: 'sent',
-        payload: log.payload,
-      });
-      
-      if (logError) {
-        console.error('Error inserting notification log:', logError);
+      const novuEnabled = await this.isNovuEnabled();
+      if (!novuEnabled) {
+        logger.warn('Novu not configured, skipping notification', {
+          action: 'trigger_notification',
+          workflowId: payload.workflowId,
+          subscriberId: payload.subscriberId
+        });
+        return { success: false, error: 'Novu not configured' };
       }
+
+      const { data, error } = await supabase.functions.invoke('trigger-notification', {
+        body: payload
+      });
+
+      if (error) {
+        logger.error('Failed to trigger notification', {
+          action: 'trigger_notification',
+          workflowId: payload.workflowId,
+          subscriberId: payload.subscriberId,
+          error: error.message
+        });
+        throw error;
+      }
+
+      logger.info('Notification triggered successfully', {
+        action: 'trigger_notification',
+        workflowId: payload.workflowId,
+        subscriberId: payload.subscriberId,
+        transactionId: data?.transactionId
+      });
+
+      return { success: true };
     } catch (error) {
-      console.error('Error logging notification:', error);
+      logger.error('Error triggering notification', {
+        action: 'trigger_notification',
+        workflowId: payload.workflowId,
+        subscriberId: payload.subscriberId,
+        error: error instanceof Error ? error.message : String(error)
+      });
+
+      return {
+        success: false,
+        error: 'Failed to trigger notification'
+      };
     }
   }
 
   /**
-   * Notify all moderators about a new submission
+   * Notify moderators (legacy method for backward compatibility)
    */
   async notifyModerators(payload: {
     submission_id: string;
     submission_type: string;
     submitter_name: string;
     action: string;
-  }): Promise<{ success: boolean; count: number; error?: string }> {
+  }): Promise<void> {
     try {
-      const { data, error } = await supabase.functions.invoke('notify-moderators-submission', {
-        body: payload,
+      const { error } = await supabase.functions.invoke('notify-moderators-submission', {
+        body: payload
       });
 
       if (error) {
-        console.error('Edge function error notifying moderators:', error);
+        logger.error('Failed to notify moderators', {
+          action: 'notify_moderators',
+          submissionId: payload.submission_id,
+          error: error.message
+        });
         throw error;
       }
 
-      console.log('Moderators notified successfully:', data);
-      return { 
-        success: true, 
-        count: data?.count || 0 
-      };
-    } catch (error: unknown) {
-      console.error('Error notifying moderators:', error);
-      return { 
-        success: false, 
-        count: 0,
-        error: this.extractErrorMessage(error) 
-      };
+      logger.info('Moderators notified successfully', {
+        action: 'notify_moderators',
+        submissionId: payload.submission_id
+      });
+    } catch (error) {
+      logger.error('Error notifying moderators', {
+        action: 'notify_moderators',
+        submissionId: payload.submission_id,
+        error: error instanceof Error ? error.message : String(error)
+      });
     }
   }
 
   /**
-   * Check if Novu is enabled
+   * Check if notifications are enabled
    */
   isEnabled(): boolean {
-    return this.isNovuEnabled;
+    return true; // Always return true, actual check happens in isNovuEnabled()
   }
 }
 
diff --git a/src/lib/notificationValidation.ts b/src/lib/notificationValidation.ts
new file mode 100644
index 00000000..e80c9c1a
--- /dev/null
+++ b/src/lib/notificationValidation.ts
@@ -0,0 +1,64 @@
+import { z } from 'zod';
+import type { NotificationPreferences } from '@/types/notifications';
+
+/**
+ * Schema for channel preferences
+ */
+export const channelPreferencesSchema = z.object({
+  in_app: z.boolean(),
+  email: z.boolean(),
+  push: z.boolean(),
+  sms: z.boolean()
+});
+
+/**
+ * Schema for workflow preferences (dynamic keys)
+ */
+export const workflowPreferencesSchema = z.record(z.string(), z.boolean());
+
+/**
+ * Schema for frequency settings
+ */
+export const frequencySettingsSchema = z.object({
+  digest: z.enum(['realtime', 'hourly', 'daily', 'weekly'] as const),
+  max_per_hour: z.number().int().min(1).max(999)
+});
+
+/**
+ * Complete notification preferences schema
+ */
+export const notificationPreferencesSchema = z.object({
+  channelPreferences: channelPreferencesSchema,
+  workflowPreferences: workflowPreferencesSchema,
+  frequencySettings: frequencySettingsSchema
+});
+
+/**
+ * Schema for subscriber data
+ */
+export const subscriberDataSchema = z.object({
+  subscriberId: z.string().uuid('Invalid subscriber ID'),
+  email: z.string().email('Invalid email').optional(),
+  firstName: z.string().max(100).optional(),
+  lastName: z.string().max(100).optional(),
+  phone: z.string().max(20).optional(),
+  avatar: z.string().url('Invalid avatar URL').optional(),
+  data: z.record(z.string(), z.any()).optional()
+});
+
+/**
+ * Default notification preferences for new users
+ */
+export const DEFAULT_NOTIFICATION_PREFERENCES: NotificationPreferences = {
+  channelPreferences: {
+    in_app: true,
+    email: true,
+    push: false,
+    sms: false
+  },
+  workflowPreferences: {},
+  frequencySettings: {
+    digest: 'daily',
+    max_per_hour: 10
+  }
+};
diff --git a/src/types/notifications.ts b/src/types/notifications.ts
new file mode 100644
index 00000000..d1ad93a6
--- /dev/null
+++ b/src/types/notifications.ts
@@ -0,0 +1,78 @@
+/**
+ * Notification Type Definitions
+ * 
+ * Centralized types for notification system.
+ * Follows project patterns for type safety and validation.
+ */
+
+/**
+ * Channel preferences for receiving notifications
+ */
+export interface ChannelPreferences {
+  in_app: boolean;
+  email: boolean;
+  push: boolean;
+  sms: boolean;
+}
+
+/**
+ * Per-workflow notification preferences
+ */
+export interface WorkflowPreferences {
+  [workflowId: string]: boolean;
+}
+
+/**
+ * Notification frequency control settings
+ */
+export interface FrequencySettings {
+  digest: 'realtime' | 'hourly' | 'daily' | 'weekly';
+  max_per_hour: number;
+}
+
+/**
+ * Complete notification preferences structure
+ */
+export interface NotificationPreferences {
+  channelPreferences: ChannelPreferences;
+  workflowPreferences: WorkflowPreferences;
+  frequencySettings: FrequencySettings;
+}
+
+/**
+ * Notification template from database
+ */
+export interface NotificationTemplate {
+  id: string;
+  workflow_id: string;
+  novu_workflow_id: string | null;
+  name: string;
+  description: string | null;
+  category: string;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+}
+
+/**
+ * Subscriber data for Novu
+ */
+export interface SubscriberData {
+  subscriberId: string;
+  email?: string;
+  firstName?: string;
+  lastName?: string;
+  phone?: string;
+  avatar?: string;
+  data?: Record<string, any>;
+}
+
+/**
+ * Notification payload for triggering workflows
+ */
+export interface NotificationPayload {
+  workflowId: string;
+  subscriberId: string;
+  payload: Record<string, any>;
+  overrides?: Record<string, any>;
+}