diff --git a/apps/lib/core/cache/cache_invalidator.dart b/apps/lib/core/cache/cache_invalidator.dart
new file mode 100644
index 0000000..b6e3181
--- /dev/null
+++ b/apps/lib/core/cache/cache_invalidator.dart
@@ -0,0 +1,27 @@
+import 'dart:async';
+
+import 'hybrid_cache_store.dart';
+
+class CacheInvalidator {
+  final HybridCacheStore? _store;
+  final Set<String> _invalidated = <String>{};
+
+  CacheInvalidator({HybridCacheStore? store}) : _store = store;
+
+  void invalidate(String key) {
+    _invalidated.add(key);
+    final removeFuture = _store?.remove(key);
+    if (removeFuture != null) {
+      unawaited(removeFuture);
+    }
+  }
+
+  void invalidateCalendarDay(DateTime date) {
+    final month = '${date.year}-${date.month.toString().padLeft(2, '0')}';
+    final day = '$month-${date.day.toString().padLeft(2, '0')}';
+    invalidate('calendar:day:$day');
+    invalidate('calendar:month:$month');
+  }
+
+  bool wasInvalidated(String key) => _invalidated.contains(key);
+}
diff --git a/apps/lib/core/di/injection.dart b/apps/lib/core/di/injection.dart
index 60c3822..a7557fc 100644
--- a/apps/lib/core/di/injection.dart
+++ b/apps/lib/core/di/injection.dart
@@ -2,6 +2,10 @@ import 'package:dio/dio.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:get_it/get_it.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import '../cache/cache_invalidator.dart';
+import '../cache/hybrid_cache_store.dart';
+import '../cache/memory_cache_store.dart';
+import '../cache/persistent_cache_store.dart';
 import '../api/api_client.dart';
 import '../api/i_api_client.dart';
 import '../storage/token_storage.dart';
@@ -56,6 +60,19 @@ Future<void> configureDependencies() async {
   final sharedPreferences = await SharedPreferences.getInstance();
   sl.registerSingleton<SharedPreferences>(sharedPreferences);
 
+  final memoryCacheStore = MemoryCacheStore();
+  final persistentCacheStore = PersistentCacheStore();
+  final hybridCacheStore = HybridCacheStore(
+    memory: memoryCacheStore,
+    persistent: persistentCacheStore,
+  );
+  sl.registerSingleton<MemoryCacheStore>(memoryCacheStore);
+  sl.registerSingleton<PersistentCacheStore>(persistentCacheStore);
+  sl.registerSingleton<HybridCacheStore>(hybridCacheStore);
+  sl.registerSingleton<CacheInvalidator>(
+    CacheInvalidator(store: hybridCacheStore),
+  );
+
   final usersApi = UsersApi(apiClient);
   sl.registerSingleton<UsersApi>(usersApi);
 
diff --git a/apps/test/core/cache/cache_invalidator_test.dart b/apps/test/core/cache/cache_invalidator_test.dart
new file mode 100644
index 0000000..a41635c
--- /dev/null
+++ b/apps/test/core/cache/cache_invalidator_test.dart
@@ -0,0 +1,11 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:social_app/core/cache/cache_invalidator.dart';
+
+void main() {
+  test('invalidate calendar day should also invalidate month key', () {
+    final inv = CacheInvalidator();
+    inv.invalidateCalendarDay(DateTime(2026, 3, 20));
+    expect(inv.wasInvalidated('calendar:day:2026-03-20'), true);
+    expect(inv.wasInvalidated('calendar:month:2026-03'), true);
+  });
+}