diff --git a/lib/services/ad_config.dart b/lib/services/ad_config.dart
new file mode 100644
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+++ b/lib/services/ad_config.dart
@@ -0,0 +1,56 @@
+// lib/services/ad_config.dart
+import 'dart:io' show Platform;
+
+import 'package:flutter/foundation.dart';
+
+/// Ad-unit and app IDs. Dev/test builds use Google's official sample IDs,
+/// which serve real test ads and never trigger an AdMob policy strike. The
+/// owner replaces the `_real*` constants (and the two native manifests'
+/// APPLICATION_ID) with the AdMob console values for release.
+///
+/// `--dart-define=USE_TEST_ADS=true` forces test IDs even in a release build,
+/// for store-review smoke tests on real devices.
+class AdConfig {
+  static const _forceTest =
+      bool.fromEnvironment('USE_TEST_ADS', defaultValue: false);
+
+  static bool get useTestIds => kDebugMode || _forceTest;
+
+  // --- Google official test ad units ---
+  static const _testInterstitialAndroid =
+      'ca-app-pub-3940256099942544/1033173712';
+  static const _testInterstitialIos =
+      'ca-app-pub-3940256099942544/4411468910';
+  static const _testRewardedAndroid =
+      'ca-app-pub-3940256099942544/5224354917';
+  static const _testRewardedIos = 'ca-app-pub-3940256099942544/1712485313';
+  static const _testBannerAndroid = 'ca-app-pub-3940256099942544/6300978111';
+  static const _testBannerIos = 'ca-app-pub-3940256099942544/2934735716';
+
+  // --- Owner replaces these with real AdMob console unit IDs ---
+  static const _realInterstitialAndroid = 'TODO_REAL_INTERSTITIAL_ANDROID';
+  static const _realInterstitialIos = 'TODO_REAL_INTERSTITIAL_IOS';
+  static const _realRewardedAndroid = 'TODO_REAL_REWARDED_ANDROID';
+  static const _realRewardedIos = 'TODO_REAL_REWARDED_IOS';
+  static const _realBannerAndroid = 'TODO_REAL_BANNER_ANDROID';
+  static const _realBannerIos = 'TODO_REAL_BANNER_IOS';
+
+  static String _pick(String testA, String testI, String realA, String realI) {
+    final android = useTestIds ? testA : realA;
+    final ios = useTestIds ? testI : realI;
+    return Platform.isAndroid ? android : ios;
+  }
+
+  static String get interstitial => _pick(_testInterstitialAndroid,
+      _testInterstitialIos, _realInterstitialAndroid, _realInterstitialIos);
+
+  static String get rewarded => _pick(_testRewardedAndroid, _testRewardedIos,
+      _realRewardedAndroid, _realRewardedIos);
+
+  static String get banner => _pick(
+      _testBannerAndroid, _testBannerIos, _realBannerAndroid, _realBannerIos);
+
+  /// Non-consumable product id for the "remove ads" purchase. Must match the
+  /// product created in App Store Connect and Google Play Console.
+  static const removeAdsProductId = 'remove_ads';
+}