diff --git a/lib/components/event_list_tile.dart b/lib/components/event_list_tile.dart
index 0f748c7..69f8cf4 100644
--- a/lib/components/event_list_tile.dart
+++ b/lib/components/event_list_tile.dart
@@ -20,13 +20,14 @@ class EventListTile extends StatelessWidget {
     FavoritesProvider favProvider =
     Provider.of<FavoritesProvider>(context, listen: true);
     bool isFavorite = favProvider.isInFavorites(item.name);
+    String imageUrl = item.imageUrl ?? '';
     return ListTile(
-      leading: item.imageUrl!.startsWith("http") ?
+      leading: imageUrl.startsWith("http") ?
       SizedBox(
           width: 100.0, // Diameter of CircleAvatar
           height: 100.0,
           child: CachedNetworkImage(
-            imageUrl: item.imageUrl ?? '',
+            imageUrl: imageUrl,
             placeholder: (context, url) =>
                 FittedBox(
                   child: CircularProgressIndicator(),
diff --git a/lib/controls/nav_bar.dart b/lib/controls/nav_bar.dart
index acbeeaf..0415a1a 100644
--- a/lib/controls/nav_bar.dart
+++ b/lib/controls/nav_bar.dart
@@ -29,10 +29,10 @@ class NavBar extends StatefulWidget {
   static final List<Widget> _widgetOptions = <Widget>[
     const HomePage(), // 0
     const EventsPage(), // 1
-    const TracksPage(), // 2
-    const SpeakersPage(), // 3
-    const RoomsPage(), // 4
-    const PreferencesPage(), // 5
+    TracksPage(), // 2
+    SpeakersPage(), // 3
+    RoomsPage(), // 4
+    PreferencesPage(), // 5
     const TravelPage(), // 6
     const AboutPage(), // 7
   ];
diff --git a/lib/data/appProviders/preferences_provider.dart b/lib/data/appProviders/preferences_provider.dart
index 89906c5..ef188a0 100644
--- a/lib/data/appProviders/preferences_provider.dart
+++ b/lib/data/appProviders/preferences_provider.dart
@@ -1,3 +1,4 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:shared_preferences/shared_preferences.dart' show SharedPreferences;
 
@@ -68,6 +69,28 @@ class PreferencesProvider {
     await prefs.setBool(_calendarColorByRoomKey, value);
   }
 
+  // ---------------------------------------------------------
+  static const String _useTestDataKey = 'useTestData';
+  static final ValueNotifier<bool> useTestDataNotifier = ValueNotifier(false);
+
+  static Future<void> loadUseTestData() async {
+    bool value = false;
+    if (kDebugMode) {
+      final prefs = await SharedPreferences.getInstance();
+      value = prefs.getBool(_useTestDataKey) ?? false; // Default
+    }
+    useTestDataNotifier.value = value;
+  }
+
+  static Future<void> setUseTestData(bool value) async {
+    if (kDebugMode) {
+      useTestDataNotifier.value = value;
+      final prefs = await SharedPreferences.getInstance();
+      await prefs.setBool(_useTestDataKey, value);
+    } else {
+      useTestDataNotifier.value = false;
+    }
+  }
   // ---------------------------------------------------------
   static const String _isDayViewKey = 'isDayView';
 
diff --git a/lib/data/dataProviders/events_provider.dart b/lib/data/dataProviders/events_provider.dart
index 68860d0..2f4615d 100644
--- a/lib/data/dataProviders/events_provider.dart
+++ b/lib/data/dataProviders/events_provider.dart
@@ -1,8 +1,10 @@
 import 'dart:convert';
 
-import 'package:flutter/material.dart';
+import 'package:flutter/foundation.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/gsheets_provider.dart';
 import 'package:iccm_eu_app/data/model/event_data.dart';
+import 'package:iccm_eu_app/data/testData/test_data.dart';
 import 'package:iccm_eu_app/utils/debug.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -27,16 +29,21 @@ class EventsProvider with ChangeNotifier  {
   }
 
   void updateCache() {
-    // Process raw data from GsheetsProvider and update _tracks
-    var data = _gsheetsProvider.getEventData();
-    if (data != null && data.isNotEmpty) {
+    if (kDebugMode && PreferencesProvider.useTestDataNotifier.value) {
       _cacheClear();
-      for (final itemData in data) {
-        _cacheAdd(EventData.fromItemData(itemData));
+      for (EventData item in TestData.getEvents()) {
+        _cacheAdd(item);
+      }
+    } else { // Process raw data from GsheetsProvider and update _tracks
+      var data = _gsheetsProvider.getEventData();
+      if (data != null && data.isNotEmpty) {
+        _cacheClear();
+        for (final itemData in data) {
+          _cacheAdd(EventData.fromItemData(itemData));
+        }
       }
-      _commit();
     }
-    notifyListeners();
+    _commit();
   }
 
   Future<void> _loadCache() async {
diff --git a/lib/data/dataProviders/gsheets_provider.dart b/lib/data/dataProviders/gsheets_provider.dart
index e191a2f..e34eea5 100644
--- a/lib/data/dataProviders/gsheets_provider.dart
+++ b/lib/data/dataProviders/gsheets_provider.dart
@@ -1,9 +1,9 @@
 import 'dart:convert';
 import 'dart:core';
 
+import 'package:flutter/foundation.dart';
 import 'package:http/http.dart' as http;
 import 'package:crypto/crypto.dart';
-import 'package:flutter/material.dart';
 import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/events_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/home_provider.dart';
@@ -172,33 +172,34 @@ class GsheetsProvider with ChangeNotifier {
       return;
     }
 
-    List<String> workSheetTitles = [];
-    workSheetTitles.add(EventsProvider.worksheetTitle);
-    workSheetTitles.add(RoomsProvider.worksheetTitle);
-    workSheetTitles.add(SpeakersProvider.worksheetTitle);
-    workSheetTitles.add(TracksProvider.worksheetTitle);
-    workSheetTitles.add(HomeProvider.worksheetTitle);
-    workSheetTitles.add(TravelProvider.worksheetTitle);
-    workSheetTitles.add(TravelDetailsProvider.worksheetTitle);
+    if (!kDebugMode || !PreferencesProvider.useTestDataNotifier.value) {
+      List<String> workSheetTitles = [];
+      workSheetTitles.add(EventsProvider.worksheetTitle);
+      workSheetTitles.add(RoomsProvider.worksheetTitle);
+      workSheetTitles.add(SpeakersProvider.worksheetTitle);
+      workSheetTitles.add(TracksProvider.worksheetTitle);
+      workSheetTitles.add(HomeProvider.worksheetTitle);
+      workSheetTitles.add(TravelProvider.worksheetTitle);
+      workSheetTitles.add(TravelDetailsProvider.worksheetTitle);
 
-    await _readWorksheets(
-        worksheetTitles: workSheetTitles,
-        errorProvider: errorProvider);
+      await _readWorksheets(
+          worksheetTitles: workSheetTitles,
+          errorProvider: errorProvider);
 
-    // Terminate if data is empty
-    if (_countDataObjects(_rawData) == 0) {
-      _isFetchingData = false;
-      Debug.msg("Fetch: Not data found.");
-      return;
-    }
-
-    String cachedChecksum = await PreferencesProvider.cachedChecksum;
-    String dataChecksum = _generateChecksum(_rawData);
+      // Terminate if data is empty
+      if (_countDataObjects(_rawData) == 0) {
+        _isFetchingData = false;
+        Debug.msg("Fetch: Not data found.");
+        return;
+      }
 
-    if (cachedChecksum != dataChecksum || force) {
-      await PreferencesProvider.setCachedChecksum(dataChecksum);
-      await PreferencesProvider.setLastUpdated(now);
+      String cachedChecksum = await PreferencesProvider.cachedChecksum;
+      String dataChecksum = _generateChecksum(_rawData);
 
+      if (cachedChecksum != dataChecksum || force) {
+        await PreferencesProvider.setCachedChecksum(dataChecksum);
+        await PreferencesProvider.setLastUpdated(now);
+      }
     }
     notifyListeners();
     Debug.msg("Fetch completed successfully.");
diff --git a/lib/data/dataProviders/rooms_provider.dart b/lib/data/dataProviders/rooms_provider.dart
index 32d8098..493bb1c 100644
--- a/lib/data/dataProviders/rooms_provider.dart
+++ b/lib/data/dataProviders/rooms_provider.dart
@@ -1,9 +1,11 @@
 import 'dart:convert';
 
-import 'package:flutter/material.dart';
+import 'package:flutter/foundation.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/gsheets_provider.dart';
 import 'package:iccm_eu_app/data/definitions/item_colors_dictionary.dart';
 import 'package:iccm_eu_app/data/model/room_data.dart';
+import 'package:iccm_eu_app/data/testData/test_data.dart';
 import 'package:iccm_eu_app/utils/debug.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -29,16 +31,22 @@ class RoomsProvider with ChangeNotifier  {
   }
 
   void updateCache() {
-    // Process raw data from GsheetsProvider and update _tracks
-    var data = _gsheetsProvider.getRoomData();
-    if (data != null && data.isNotEmpty) {
+    if (kDebugMode && PreferencesProvider.useTestDataNotifier.value) {
       _cacheClear();
-      for (final itemData in data) {
-        _cacheAdd(RoomData.fromItemData(itemData));
+      for (RoomData item in TestData.rooms) {
+        _cacheAdd(item);
+      }
+    } else {
+      // Process raw data from GsheetsProvider and update _tracks
+      var data = _gsheetsProvider.getRoomData();
+      if (data != null && data.isNotEmpty) {
+        _cacheClear();
+        for (final itemData in data) {
+          _cacheAdd(RoomData.fromItemData(itemData));
+        }
       }
-      _commit();
     }
-    notifyListeners();
+    _commit();
   }
 
   Future<void> _loadCache() async {
diff --git a/lib/data/dataProviders/speakers_provider.dart b/lib/data/dataProviders/speakers_provider.dart
index 56f463e..3e8f436 100644
--- a/lib/data/dataProviders/speakers_provider.dart
+++ b/lib/data/dataProviders/speakers_provider.dart
@@ -1,8 +1,10 @@
 import 'dart:convert';
 
-import 'package:flutter/cupertino.dart';
+import 'package:flutter/foundation.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/gsheets_provider.dart';
 import 'package:iccm_eu_app/data/model/speaker_data.dart';
+import 'package:iccm_eu_app/data/testData/test_data.dart';
 import 'package:iccm_eu_app/utils/debug.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -27,16 +29,22 @@ class SpeakersProvider with ChangeNotifier  {
   }
 
   void updateCache() {
-    // Process raw data from GsheetsProvider and update _tracks
-    var data = _gsheetsProvider.getSpeakerData();
-    if (data != null && data.isNotEmpty) {
+    if (kDebugMode && PreferencesProvider.useTestDataNotifier.value) {
       _cacheClear();
-      for (final itemData in data) {
-        _cacheAdd(SpeakerData.fromItemData(itemData));
+      for (SpeakerData item in TestData.speakers) {
+        _cacheAdd(item);
+      }
+    } else {
+      // Process raw data from GsheetsProvider and update _tracks
+      var data = _gsheetsProvider.getSpeakerData();
+      if (data != null && data.isNotEmpty) {
+        _cacheClear();
+        for (final itemData in data) {
+          _cacheAdd(SpeakerData.fromItemData(itemData));
+        }
       }
-      _commit();
     }
-    notifyListeners();
+    _commit();
   }
 
   Future<void> _loadCache() async {
diff --git a/lib/data/dataProviders/tracks_provider.dart b/lib/data/dataProviders/tracks_provider.dart
index 57bdd6d..da1b5e2 100644
--- a/lib/data/dataProviders/tracks_provider.dart
+++ b/lib/data/dataProviders/tracks_provider.dart
@@ -1,9 +1,11 @@
 import 'dart:convert';
 
-import 'package:flutter/material.dart';
+import 'package:flutter/foundation.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/gsheets_provider.dart';
 import 'package:iccm_eu_app/data/definitions/item_colors_dictionary.dart';
 import 'package:iccm_eu_app/data/model/track_data.dart';
+import 'package:iccm_eu_app/data/testData/test_data.dart';
 import 'package:iccm_eu_app/utils/debug.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -31,15 +33,24 @@ class TracksProvider with ChangeNotifier {
   }
 
   void updateCache() {
-    // Process raw data from GsheetsProvider and update _tracks
-    var data = _gsheetsProvider.getTrackData();
-    if (data != null && data.isNotEmpty) {
+    if (kDebugMode && PreferencesProvider.useTestDataNotifier.value) {
+      Debug.msg("Updating TrackData cache from TestData ($kDebugMode, ${PreferencesProvider.useTestDataNotifier.value}).");
       _cacheClear();
-      for (final itemData in data) {
-        _cacheAdd(TrackData.fromItemData(itemData));
+      for (TrackData item in TestData.tracks) {
+        _cacheAdd(item);
+      }
+    } else {
+      Debug.msg("Updating TrackData cache from GSheets ($kDebugMode, ${PreferencesProvider.useTestDataNotifier.value}).");
+      // Process raw data from GsheetsProvider and update _tracks
+      var data = _gsheetsProvider.getTrackData();
+      if (data != null && data.isNotEmpty) {
+        _cacheClear();
+        for (final itemData in data) {
+          _cacheAdd(TrackData.fromItemData(itemData));
+        }
       }
-      _commit();
     }
+    _commit();
   }
 
   Future<void> _loadCache() async {
diff --git a/lib/data/dataProviders/travel_details_provider.dart b/lib/data/dataProviders/travel_details_provider.dart
index 844c815..1d5190c 100644
--- a/lib/data/dataProviders/travel_details_provider.dart
+++ b/lib/data/dataProviders/travel_details_provider.dart
@@ -67,7 +67,6 @@ class TravelDetailsProvider with ChangeNotifier  {
     _cache.sort((a, b) => a.name.compareTo(b.name));
     _saveCache();
     _populateItemsFromCache();
-    Debug.msg("Found ${_items.length} travel elements");
     notifyListeners();
   }
 
diff --git a/lib/data/model/room_data.dart b/lib/data/model/room_data.dart
index 091ccfe..a954c0a 100644
--- a/lib/data/model/room_data.dart
+++ b/lib/data/model/room_data.dart
@@ -11,6 +11,13 @@ class RoomData extends ModelItem {
   final String details;
   late ColorsData? colors;
 
+  RoomData({
+    required this.imageUrl,
+    required this.name,
+    required this.details,
+    this.colors,
+  });
+
   RoomData._({
     required this.imageUrl,
     required this.name,
diff --git a/lib/data/model/speaker_data.dart b/lib/data/model/speaker_data.dart
index 46e3eb2..b963cb6 100644
--- a/lib/data/model/speaker_data.dart
+++ b/lib/data/model/speaker_data.dart
@@ -9,6 +9,12 @@ class SpeakerData extends ModelItem {
   @override
   final String details;
 
+  SpeakerData({
+    required this.imageUrl,
+    required this.name,
+    required this.details,
+  });
+
   SpeakerData._({
     required this.imageUrl,
     required this.name,
diff --git a/lib/data/model/track_data.dart b/lib/data/model/track_data.dart
index aa66d97..935c578 100644
--- a/lib/data/model/track_data.dart
+++ b/lib/data/model/track_data.dart
@@ -11,6 +11,13 @@ class TrackData extends ModelItem {
   final String details;
   late ColorsData? colors;
 
+  TrackData({
+    required this.imageUrl,
+    required this.name,
+    required this.details,
+    this.colors,
+  });
+
   TrackData._({
     required this.imageUrl,
     required this.name,
diff --git a/lib/data/testData/test_data.dart b/lib/data/testData/test_data.dart
new file mode 100644
index 0000000..a15f86c
--- /dev/null
+++ b/lib/data/testData/test_data.dart
@@ -0,0 +1,138 @@
+
+import 'package:iccm_eu_app/data/model/event_data.dart';
+import 'package:iccm_eu_app/data/model/room_data.dart';
+import 'package:iccm_eu_app/data/model/speaker_data.dart';
+import 'package:iccm_eu_app/data/model/track_data.dart';
+
+
+class TestData {
+  static final List<RoomData> rooms = [
+    RoomData(
+      name: 'Room 1',
+      details: 'First Room',
+      imageUrl: '',
+    ),
+    RoomData(
+      name: 'Room 2',
+      details: 'Second Room',
+      imageUrl: '',
+    ),
+    RoomData(
+      name: 'Room 3',
+      details: 'Third Room',
+      imageUrl: '',
+    ),
+    RoomData(
+      name: 'Room 4',
+      details: 'Fourth Room',
+      imageUrl: '',
+    ),
+  ];
+
+  static final List<TrackData> tracks = [
+    TrackData(
+      name: 'Track 1',
+      details: 'First Track',
+      imageUrl: '',
+    ),
+    TrackData(
+      name: 'Track 2',
+      details: 'Second Track',
+      imageUrl: '',
+    ),
+    TrackData(
+      name: 'Track 3',
+      details: 'Third Track',
+      imageUrl: '',
+    ),
+    TrackData(
+      name: 'Track 4',
+      details: 'Fourth Track',
+      imageUrl: '',
+    ),
+  ];
+
+  static final List<SpeakerData> speakers = [
+    SpeakerData(
+      name: 'Speaker 1',
+      details: 'First Speaker',
+      imageUrl: '',
+    ),
+    SpeakerData(
+      name: 'Speaker 2',
+      details: 'Second Speaker',
+      imageUrl: '',
+    ),
+    SpeakerData(
+      name: 'Speaker 3',
+      details: 'Third Speaker',
+      imageUrl: '',
+    ),
+    SpeakerData(
+      name: 'Speaker 4',
+      details: 'Fourth Speaker',
+      imageUrl: '',
+    ),
+  ];
+
+  static List<EventData> getEvents() {
+    List<EventData> items = [];
+    // From previous day to next day
+    // From 8:00 to 22:00
+    // Schedule a series of events
+    // Around now(), add a series of short events
+    DateTime now = DateTime.now();
+    DateTime scheduleStart = now.subtract(Duration(
+      hours: now.hour,
+      minutes: now.minute,
+      seconds: now.second,
+      milliseconds: now.millisecond,
+    ));
+    List<DateTime> scheduleDays = [
+      scheduleStart.subtract(Duration(days: 1)),
+      scheduleStart,
+      scheduleStart.add(Duration(days: 1)),
+    ];
+    int eventCount = 0;
+    TrackData track = tracks[0];
+    SpeakerData? speaker = speakers[0];
+    RoomData room = rooms[0];
+    for (DateTime day in scheduleDays) {
+      DateTime startTime = day.add(Duration(hours: 8));
+      while (startTime.hour < 22) {
+        Duration duration;
+        int parallel;
+        if (startTime.isAfter(now.subtract(Duration(hours: 1, minutes: 1))) &&
+            startTime.isBefore(now.add(Duration(hours: 1, minutes: 1)))) {
+          duration = Duration(hours: 0, minutes: 30);
+          parallel = 3;
+        } else {
+          duration = Duration(hours: 1, minutes: 0);
+          parallel = 0;
+        }
+        DateTime endTime = startTime.add(duration);
+        for (int i = 0; i <= parallel; i++) {
+          items.add(EventData(
+            start: startTime,
+            end: endTime,
+            name: 'Event $eventCount',
+            details: 'Details',
+            track: track.name,
+            speaker: speaker?.name,
+            room: room.name,
+          ));
+          startTime = endTime;
+          track = tracks[eventCount % tracks.length];
+          room = rooms[eventCount % rooms.length];
+          if (eventCount % 2 == 0) {
+            speaker = speakers[eventCount % speakers.length];
+          } else {
+            speaker = null;
+          }
+          eventCount ++;
+        }
+      }
+    }
+    return items;
+  }
+}
\ No newline at end of file
diff --git a/lib/pages/event_details_page.dart b/lib/pages/event_details_page.dart
index 098d278..8fa3e4f 100644
--- a/lib/pages/event_details_page.dart
+++ b/lib/pages/event_details_page.dart
@@ -63,6 +63,7 @@ class EventDetailsPage extends StatelessWidget {
     FavoritesProvider favProvider =
         Provider.of<FavoritesProvider>(context, listen: true);
     bool isFavorite = favProvider.isInFavorites(item.name);
+    String imageUrl = item.imageUrl ?? '';
 
     return Scaffold(
       appBar: AppBar(
@@ -76,9 +77,9 @@ class EventDetailsPage extends StatelessWidget {
             Column(
               mainAxisAlignment: MainAxisAlignment.center,
               children: [
-                if (item.imageUrl!.startsWith("http"))
+                if (imageUrl.startsWith("http"))
                   CachedNetworkImage(
-                    imageUrl: item.imageUrl ?? '',
+                    imageUrl: imageUrl,
                     imageBuilder: (context, imageProvider) =>
                         CircleAvatar(
                           backgroundImage: imageProvider,
diff --git a/lib/pages/events_page.dart b/lib/pages/events_page.dart
index 55be77f..6beb925 100644
--- a/lib/pages/events_page.dart
+++ b/lib/pages/events_page.dart
@@ -107,11 +107,12 @@ class DayViewCalendarState extends State<DayViewCalendar> {
   @override
   void initState() {
     super.initState();
-    _loadColorByRoom();
+    _loadPreferences();
   }
 
-  Future<void> _loadColorByRoom() async {
+  Future<void> _loadPreferences() async {
     PreferencesProvider.loadCalendarColorByRoom();
+    PreferencesProvider.loadUseTestData();
   }
 
   @override
diff --git a/lib/pages/preferences_page.dart b/lib/pages/preferences_page.dart
index 06174b7..a45cf3d 100644
--- a/lib/pages/preferences_page.dart
+++ b/lib/pages/preferences_page.dart
@@ -1,10 +1,21 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:iccm_eu_app/components/toggle_button.dart';
 import 'package:iccm_eu_app/components/toggle_is_dark_mode.dart';
 import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
+import 'package:iccm_eu_app/data/dataProviders/error_provider.dart';
+import 'package:iccm_eu_app/data/dataProviders/gsheets_provider.dart';
+import 'package:provider/provider.dart';
 
 class PreferencesPage extends StatelessWidget {
-  const PreferencesPage({super.key});
+  PreferencesPage({super.key}) {
+    _loadPreferences();
+  }
+
+  Future<void> _loadPreferences() async {
+    PreferencesProvider.loadCalendarColorByRoom();
+    PreferencesProvider.loadUseTestData();
+  }
 
   @override
   Widget build(BuildContext context) {
@@ -28,17 +39,26 @@ class PreferencesPage extends StatelessWidget {
         children: <Widget>[
           Text(
             'Preferences',
-            style: Theme.of(context).textTheme.titleLarge,
+            style: Theme
+                .of(context)
+                .textTheme
+                .titleLarge,
             textAlign: TextAlign.center,
           ),
           SizedBox(height: 16),
           Text('Theme',
-            style: Theme.of(context).textTheme.titleLarge,
+            style: Theme
+                .of(context)
+                .textTheme
+                .titleLarge,
           ),
           ToggleIsDarkModeListTile(context: context),
           const Divider(),
           Text('Calendar Colors',
-            style: Theme.of(context).textTheme.titleLarge,
+            style: Theme
+                .of(context)
+                .textTheme
+                .titleLarge,
           ),
           ValueListenableBuilder<bool>(
             valueListenable: PreferencesProvider.calendarColorByRoomNotifier,
@@ -53,6 +73,39 @@ class PreferencesPage extends StatelessWidget {
               );
             },
           ),
+          if (kDebugMode)
+            const Divider()
+          else
+            const SizedBox.shrink(),
+          if (kDebugMode)
+            Text('Test Data',
+              style: Theme
+                  .of(context)
+                  .textTheme
+                  .titleLarge,
+            )
+          else
+            const SizedBox.shrink(),
+          if (kDebugMode)
+            ValueListenableBuilder<bool>(
+              valueListenable: PreferencesProvider.useTestDataNotifier,
+              builder: (context, builderValue, child) {
+                return ToggleButtonListTile(
+                  value: builderValue,
+                  onChanged: (bool newValue) {
+                    PreferencesProvider.setUseTestData(newValue);
+                    Provider.of<GsheetsProvider>(context, listen: false).fetchData(
+                      errorProvider: Provider.of<ErrorProvider>(context, listen: false),
+                      force: true,
+                    );
+                  },
+                  title: 'Use Test Data',
+                  toggleTitle: 'Test Data',
+                );
+              },
+            )
+          else
+            const SizedBox.shrink(),
           // const Divider(),
           // const Text('Profile',
           //   style: TextStyle(
diff --git a/lib/pages/rooms_page.dart b/lib/pages/rooms_page.dart
index 6bd3878..4f5e660 100644
--- a/lib/pages/rooms_page.dart
+++ b/lib/pages/rooms_page.dart
@@ -1,10 +1,17 @@
 import 'package:flutter/material.dart';
 import 'package:iccm_eu_app/components/room_list_tile.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/rooms_provider.dart';
 import 'package:provider/provider.dart';
 
 class RoomsPage extends StatelessWidget {
-  const RoomsPage({super.key});
+  RoomsPage({super.key}) {
+    _loadPreferences();
+  }
+
+  Future<void> _loadPreferences() async {
+    PreferencesProvider.loadUseTestData();
+  }
 
   @override
   Widget build(BuildContext context) {
diff --git a/lib/pages/speakers_page.dart b/lib/pages/speakers_page.dart
index 958c40b..bd5a426 100644
--- a/lib/pages/speakers_page.dart
+++ b/lib/pages/speakers_page.dart
@@ -1,10 +1,17 @@
 import 'package:flutter/material.dart';
 import 'package:iccm_eu_app/components/speaker_list_tile.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/speakers_provider.dart';
 import 'package:provider/provider.dart';
 
 class SpeakersPage extends StatelessWidget {
-  const SpeakersPage({super.key});
+  SpeakersPage({super.key}) {
+    _loadPreferences();
+  }
+
+  Future<void> _loadPreferences() async {
+    PreferencesProvider.loadUseTestData();
+  }
 
   @override
   Widget build(BuildContext context) {
diff --git a/lib/pages/tracks_page.dart b/lib/pages/tracks_page.dart
index c3860cb..deac908 100644
--- a/lib/pages/tracks_page.dart
+++ b/lib/pages/tracks_page.dart
@@ -1,10 +1,17 @@
 import 'package:flutter/material.dart';
 import 'package:iccm_eu_app/components/track_list_tile.dart';
+import 'package:iccm_eu_app/data/appProviders/preferences_provider.dart';
 import 'package:iccm_eu_app/data/dataProviders/tracks_provider.dart';
 import 'package:provider/provider.dart';
 
 class TracksPage extends StatelessWidget {
-  const TracksPage({super.key});
+  TracksPage({super.key}) {
+    _loadPreferences();
+  }
+
+  Future<void> _loadPreferences() async {
+    PreferencesProvider.loadUseTestData();
+  }
 
   @override
   Widget build(BuildContext context) {