diff --git a/packages/realm_dart/lib/src/handles/app_handle.dart b/packages/realm_dart/lib/src/handles/app_handle.dart
index 47b326f03..e2a57a8e4 100644
--- a/packages/realm_dart/lib/src/handles/app_handle.dart
+++ b/packages/realm_dart/lib/src/handles/app_handle.dart
@@ -1,5 +1,38 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/app_handle.dart'
-    if (dart.library.js_interop) 'web/app_handle.dart';
+import '../../realm.dart';
+
+import 'credentials_handle.dart';
+import 'native/app_handle.dart' if (dart.library.js_interop) 'web/app_handle.dart' as impl;
+import 'user_handle.dart';
+
+abstract interface class AppHandle {
+  factory AppHandle.from(AppConfiguration configuration) = impl.AppHandle.from;
+  static AppHandle? get(String id, String? baseUrl) => impl.AppHandle.get(id, baseUrl);
+
+  String get id;
+
+  UserHandle? get currentUser;
+  List<UserHandle> get users;
+  Future<UserHandle> logIn(CredentialsHandle credentials);
+  Future<void> removeUser(UserHandle user);
+  void switchUser(UserHandle user);
+  Future<void> refreshCustomData(UserHandle user);
+
+  void reconnect();
+  String get baseUrl;
+  Future<void> updateBaseUrl(Uri? baseUrl);
+
+  Future<void> registerUser(String email, String password);
+  Future<void> confirmUser(String token, String tokenId);
+  Future<void> resendConfirmation(String email);
+
+  Future<void> completeResetPassword(String password, String token, String tokenId);
+  Future<void> requestResetPassword(String email);
+  Future<void> callResetPasswordFunction(String email, String password, String? argsAsJSON);
+  Future<void> retryCustomConfirmationFunction(String email);
+  Future<void> deleteUser(UserHandle user);
+  bool resetRealm(String realmPath);
+  Future<String> callAppFunction(UserHandle user, String functionName, String? argsAsJSON);
+}
diff --git a/packages/realm_dart/lib/src/handles/async_open_task_handle.dart b/packages/realm_dart/lib/src/handles/async_open_task_handle.dart
index 43c4aeae2..47d988585 100644
--- a/packages/realm_dart/lib/src/handles/async_open_task_handle.dart
+++ b/packages/realm_dart/lib/src/handles/async_open_task_handle.dart
@@ -1,5 +1,20 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/async_open_task_handle.dart'
-    if (dart.library.js_interop) 'web/async_open_task_handle.dart';
+import '../realm_class.dart';
+import 'handle_base.dart';
+import 'native/async_open_task_handle.dart' if (dart.library.js_interop) 'web/async_open_task_handle.dart' as impl;
+import 'realm_handle.dart';
+
+abstract interface class AsyncOpenTaskHandle extends HandleBase {
+  factory AsyncOpenTaskHandle.from(FlexibleSyncConfiguration config) = impl.AsyncOpenTaskHandle.from;
+
+  Future<RealmHandle> openAsync(CancellationToken? cancellationToken);
+  void cancel();
+
+  AsyncOpenTaskProgressNotificationTokenHandle registerProgressNotifier(
+    RealmAsyncOpenProgressNotificationsController controller,
+  );
+}
+
+abstract class AsyncOpenTaskProgressNotificationTokenHandle extends HandleBase {}
\ No newline at end of file
diff --git a/packages/realm_dart/lib/src/handles/collection_changes_handle.dart b/packages/realm_dart/lib/src/handles/collection_changes_handle.dart
index 8988dae68..e8295ba1d 100644
--- a/packages/realm_dart/lib/src/handles/collection_changes_handle.dart
+++ b/packages/realm_dart/lib/src/handles/collection_changes_handle.dart
@@ -1,5 +1,9 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/collection_changes_handle.dart'
-    if (dart.library.js_interop) 'web/collection_changes_handle.dart';
+import '../collections.dart';
+import 'handle_base.dart';
+
+abstract interface class CollectionChangesHandle extends HandleBase {
+  CollectionChanges get changes;
+}
diff --git a/packages/realm_dart/lib/src/handles/handle_base.dart b/packages/realm_dart/lib/src/handles/handle_base.dart
index 3cc73da68..bf255de0e 100644
--- a/packages/realm_dart/lib/src/handles/handle_base.dart
+++ b/packages/realm_dart/lib/src/handles/handle_base.dart
@@ -1,5 +1,9 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/handle_base.dart'
-    if (dart.library.js_interop) 'web/handle_base.dart';
+abstract class HandleBase {
+  bool get released;
+  bool get isUnowned;
+  void releaseCore();
+  void release();
+}
diff --git a/packages/realm_dart/lib/src/handles/list_handle.dart b/packages/realm_dart/lib/src/handles/list_handle.dart
index f6ebbab17..4606fe831 100644
--- a/packages/realm_dart/lib/src/handles/list_handle.dart
+++ b/packages/realm_dart/lib/src/handles/list_handle.dart
@@ -1,5 +1,32 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/list_handle.dart'
-    if (dart.library.js_interop) 'web/list_handle.dart';
+import '../realm_dart.dart';
+import 'handle_base.dart';
+import 'notification_token_handle.dart';
+import 'object_handle.dart';
+import 'realm_handle.dart';
+import 'results_handle.dart';
+
+abstract interface class ListHandle extends HandleBase {
+  bool get isValid;
+  int get size;
+
+  // TODO: Consider splitting into two methods
+  void addOrUpdateAt(int index, Object? value, bool insert);
+  // TODO: avoid taking the [realm] parameter
+  void addOrUpdateCollectionAt(Realm realm, int index, RealmValue value, bool insert);
+  ResultsHandle asResults();
+  void clear();
+  void deleteAll();
+  // TODO: avoid taking the [realm] parameter
+  Object? elementAt(Realm realm, int index);
+  int indexOf(Object? value);
+  ObjectHandle insertEmbeddedAt(int index);
+  void move(int from, int to);
+  ResultsHandle query(String query, List<Object?> args);
+  void removeAt(int index);
+  ListHandle? resolveIn(RealmHandle frozenRealm);
+  ObjectHandle setEmbeddedAt(int index);
+  NotificationTokenHandle subscribeForNotifications(NotificationsController controller);
+}
diff --git a/packages/realm_dart/lib/src/handles/map_changes_handle.dart b/packages/realm_dart/lib/src/handles/map_changes_handle.dart
index 83cc550db..a90197e6b 100644
--- a/packages/realm_dart/lib/src/handles/map_changes_handle.dart
+++ b/packages/realm_dart/lib/src/handles/map_changes_handle.dart
@@ -1,5 +1,9 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/map_changes_handle.dart'
-    if (dart.library.js_interop) 'web/map_changes_handle.dart';
+import '../collections.dart';
+import 'handle_base.dart';
+
+abstract interface class MapChangesHandle extends HandleBase {
+  MapChanges get changes;
+}
\ No newline at end of file
diff --git a/packages/realm_dart/lib/src/handles/map_handle.dart b/packages/realm_dart/lib/src/handles/map_handle.dart
index afc43b6be..2ffa43557 100644
--- a/packages/realm_dart/lib/src/handles/map_handle.dart
+++ b/packages/realm_dart/lib/src/handles/map_handle.dart
@@ -1,5 +1,31 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/map_handle.dart'
-    if (dart.library.js_interop) 'web/map_handle.dart';
+import '../realm_class.dart';
+import 'handle_base.dart';
+import 'notification_token_handle.dart';
+import 'object_handle.dart';
+import 'realm_handle.dart';
+import 'results_handle.dart';
+
+abstract interface class MapHandle extends HandleBase {
+  bool get isValid;
+  ResultsHandle get keys;
+  int get size;
+  ResultsHandle get values;
+
+  void clear();
+  bool containsKey(String key);
+  bool containsValue(Object? value);
+  // TODO: avoid taking a [Realm] as parameter (wrong layer)
+  Object? find(Realm realm, String key);
+  int indexOf(Object? value);
+  void insert(String key, Object? value);
+  // TODO: avoid taking a [Realm] as parameter (wrong layer)
+  void insertCollection(Realm realm, String key, RealmValue value);
+  ObjectHandle insertEmbedded(String key);
+  ResultsHandle query(String query, List<Object?> args);
+  bool remove(String key);
+  MapHandle? resolveIn(RealmHandle frozenRealm);
+  NotificationTokenHandle subscribeForNotifications(NotificationsController controller);
+}
diff --git a/packages/realm_dart/lib/src/handles/mutable_subscription_set_handle.dart b/packages/realm_dart/lib/src/handles/mutable_subscription_set_handle.dart
index 557f97f1d..06cb2a811 100644
--- a/packages/realm_dart/lib/src/handles/mutable_subscription_set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/mutable_subscription_set_handle.dart
@@ -1,5 +1,18 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/mutable_subscription_set_handle.dart'
-    if (dart.library.js_interop) 'web/mutable_subscription_set_handle.dart';
+import 'results_handle.dart';
+import 'subscription_handle.dart';
+import 'subscription_set_handle.dart';
+
+abstract interface class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
+  SubscriptionSetHandle commit();
+
+  SubscriptionHandle insertOrAssignSubscription(ResultsHandle results, String? name, bool update);
+
+  bool erase(SubscriptionHandle subscription);
+  bool eraseByName(String name);
+  bool eraseByResults(ResultsHandle results);
+
+  void clear();
+}
diff --git a/packages/realm_dart/lib/src/handles/native/app_handle.dart b/packages/realm_dart/lib/src/handles/native/app_handle.dart
index 38b1900b2..63f09d030 100644
--- a/packages/realm_dart/lib/src/handles/native/app_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/app_handle.dart
@@ -8,7 +8,6 @@ import 'dart:isolate';
 
 import '../../init.dart';
 import '../../realm_class.dart';
-import '../../scheduler.dart';
 import 'convert.dart';
 import 'convert_native.dart';
 import 'credentials_handle.dart';
@@ -19,9 +18,12 @@ import 'http_transport_handle.dart';
 import 'realm_bindings.dart';
 import 'realm_core.dart';
 import 'realm_library.dart';
+import 'scheduler_handle.dart';
 import 'user_handle.dart';
 
-class AppHandle extends HandleBase<realm_app> {
+import '../app_handle.dart' as intf;
+
+class AppHandle extends HandleBase<realm_app> implements intf.AppHandle {
   AppHandle(Pointer<realm_app> pointer) : super(pointer, 16);
 
   static bool _firstTime = true;
@@ -51,10 +53,12 @@ class AppHandle extends HandleBase<realm_app> {
     });
   }
 
+  @override
   UserHandle? get currentUser {
     return realmLib.realm_app_get_current_user(pointer).convert(UserHandle.new);
   }
 
+  @override
   List<UserHandle> get users => using((arena) => _getUsers(arena));
 
   List<UserHandle> _getUsers(Arena arena, {int expectedSize = 2}) {
@@ -76,7 +80,8 @@ class AppHandle extends HandleBase<realm_app> {
     return result;
   }
 
-  Future<void> removeUser(UserHandle user) {
+  @override
+  Future<void> removeUser(covariant UserHandle user) {
     final completer = Completer<void>();
     realmLib
         .realm_app_remove_user(
@@ -90,7 +95,8 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
-  void switchUser(UserHandle user) {
+  @override
+  void switchUser(covariant UserHandle user) {
     using((arena) {
       realmLib
           .realm_app_switch_user(
@@ -101,13 +107,16 @@ class AppHandle extends HandleBase<realm_app> {
     });
   }
 
+  @override
   void reconnect() => realmLib.realm_app_sync_client_reconnect(pointer);
 
+  @override
   String get baseUrl {
     final customDataPtr = realmLib.realm_app_get_base_url(pointer);
     return customDataPtr.cast<Utf8>().toRealmDartString(freeRealmMemory: true)!;
   }
 
+  @override
   Future<void> updateBaseUrl(Uri? baseUrl) {
     final completer = Completer<void>();
     using((arena) {
@@ -124,7 +133,8 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
-  Future<void> refreshCustomData(UserHandle user) {
+  @override
+  Future<void> refreshCustomData(covariant UserHandle user) {
     final completer = Completer<void>();
     realmLib
         .realm_app_refresh_custom_data(
@@ -138,10 +148,12 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   String get id {
     return realmLib.realm_app_get_app_id(pointer).cast<Utf8>().toRealmDartString()!;
   }
 
+  @override
   Future<UserHandle> logIn(CredentialsHandle credentials) {
     final completer = Completer<UserHandle>();
     realmLib
@@ -156,6 +168,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> registerUser(String email, String password) {
     final completer = Completer<void>();
     using((arena) {
@@ -173,6 +186,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> confirmUser(String token, String tokenId) {
     final completer = Completer<void>();
     using((arena) {
@@ -190,6 +204,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> resendConfirmation(String email) {
     final completer = Completer<void>();
     using((arena) {
@@ -206,6 +221,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> completeResetPassword(String password, String token, String tokenId) {
     final completer = Completer<void>();
     using((arena) {
@@ -224,6 +240,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> requestResetPassword(String email) {
     final completer = Completer<void>();
     using((arena) {
@@ -240,6 +257,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> callResetPasswordFunction(String email, String password, String? argsAsJSON) {
     final completer = Completer<void>();
     using((arena) {
@@ -258,6 +276,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   Future<void> retryCustomConfirmationFunction(String email) {
     final completer = Completer<void>();
     using((arena) {
@@ -274,7 +293,8 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
-  Future<void> deleteUser(UserHandle user) {
+  @override
+  Future<void> deleteUser(covariant UserHandle user) {
     final completer = Completer<void>();
     realmLib
         .realm_app_delete_user(
@@ -288,6 +308,7 @@ class AppHandle extends HandleBase<realm_app> {
     return completer.future;
   }
 
+  @override
   bool resetRealm(String realmPath) {
     return using((arena) {
       final didRun = arena<Bool>();
@@ -302,7 +323,8 @@ class AppHandle extends HandleBase<realm_app> {
     });
   }
 
-  Future<String> callAppFunction(UserHandle user, String functionName, String? argsAsJSON) {
+  @override
+  Future<String> callAppFunction(covariant UserHandle user, String functionName, String? argsAsJSON) {
     return using((arena) {
       final completer = Completer<String>();
       realmLib
@@ -333,7 +355,7 @@ Pointer<Void> createAsyncFunctionCallbackUserdata(Completer<String> completer) {
   final userdata = realmLib.realm_dart_userdata_async_new(
     completer,
     callback.cast(),
-    scheduler.handle.pointer,
+    schedulerHandle.pointer,
   );
 
   return userdata.cast();
@@ -361,7 +383,7 @@ Pointer<Void> createAsyncCallbackUserdata(Completer<void> completer) {
   final userdata = realmLib.realm_dart_userdata_async_new(
     completer,
     callback.cast(),
-    scheduler.handle.pointer,
+    schedulerHandle.pointer,
   );
 
   return userdata.cast();
diff --git a/packages/realm_dart/lib/src/handles/native/async_open_task_handle.dart b/packages/realm_dart/lib/src/handles/native/async_open_task_handle.dart
index ee938a75c..7a6d202e4 100644
--- a/packages/realm_dart/lib/src/handles/native/async_open_task_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/async_open_task_handle.dart
@@ -6,14 +6,16 @@ import 'error_handling.dart';
 import 'realm_bindings.dart';
 
 import '../../realm_dart.dart';
-import '../../scheduler.dart';
 import 'config_handle.dart';
 import 'handle_base.dart';
 import 'realm_handle.dart';
 import 'realm_library.dart';
+import 'scheduler_handle.dart';
 import 'session_handle.dart';
 
-class AsyncOpenTaskHandle extends HandleBase<realm_async_open_task_t> {
+import '../async_open_task_handle.dart' as intf;
+
+class AsyncOpenTaskHandle extends HandleBase<realm_async_open_task_t> implements intf.AsyncOpenTaskHandle {
   AsyncOpenTaskHandle(Pointer<realm_async_open_task_t> pointer) : super(pointer, 32);
 
   factory AsyncOpenTaskHandle.from(FlexibleSyncConfiguration config) {
@@ -27,7 +29,7 @@ class AsyncOpenTaskHandle extends HandleBase<realm_async_open_task_t> {
     if (!completer.isCancelled) {
       final callback =
           Pointer.fromFunction<Void Function(Handle, Pointer<realm_thread_safe_reference> realm, Pointer<realm_async_error_t> error)>(_openRealmAsyncCallback);
-      final userData = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), scheduler.handle.pointer);
+      final userData = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), schedulerHandle.pointer);
       realmLib.realm_async_open_task_start(
         pointer,
         realmLib.addresses.realm_dart_async_open_task_callback,
@@ -46,7 +48,7 @@ class AsyncOpenTaskHandle extends HandleBase<realm_async_open_task_t> {
     RealmAsyncOpenProgressNotificationsController controller,
   ) {
     final callback = Pointer.fromFunction<Void Function(Handle, Uint64, Uint64, Double)>(syncProgressCallback);
-    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), scheduler.handle.pointer);
+    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), schedulerHandle.pointer);
     return AsyncOpenTaskProgressNotificationTokenHandle(
       realmLib.realm_async_open_task_register_download_progress_notifier(
         pointer,
@@ -58,7 +60,8 @@ class AsyncOpenTaskHandle extends HandleBase<realm_async_open_task_t> {
   }
 }
 
-class AsyncOpenTaskProgressNotificationTokenHandle extends HandleBase<realm_async_open_task_progress_notification_token_t> {
+class AsyncOpenTaskProgressNotificationTokenHandle extends HandleBase<realm_async_open_task_progress_notification_token_t>
+    implements intf.AsyncOpenTaskProgressNotificationTokenHandle {
   AsyncOpenTaskProgressNotificationTokenHandle(Pointer<realm_async_open_task_progress_notification_token_t> pointer) : super(pointer, 40);
 }
 
@@ -75,6 +78,6 @@ void _openRealmAsyncCallback(Object userData, Pointer<realm_thread_safe_referenc
       return;
     }
 
-    completer.complete(RealmHandle(realmLib.realm_from_thread_safe_reference(realmSafePtr, scheduler.handle.pointer)));
+    completer.complete(RealmHandle(realmLib.realm_from_thread_safe_reference(realmSafePtr, schedulerHandle.pointer)));
   });
 }
diff --git a/packages/realm_dart/lib/src/handles/native/collection_changes_handle.dart b/packages/realm_dart/lib/src/handles/native/collection_changes_handle.dart
index 56a26ce93..8362e82ad 100644
--- a/packages/realm_dart/lib/src/handles/native/collection_changes_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/collection_changes_handle.dart
@@ -11,9 +11,12 @@ import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
 
-class CollectionChangesHandle extends HandleBase<realm_collection_changes> {
+import '../collection_changes_handle.dart' as intf;
+
+class CollectionChangesHandle extends HandleBase<realm_collection_changes> implements intf.CollectionChangesHandle {
   CollectionChangesHandle(Pointer<realm_collection_changes> pointer) : super(pointer, 256);
 
+  @override
   CollectionChanges get changes {
     return using((arena) {
       final outNumDeletions = arena<Size>();
diff --git a/packages/realm_dart/lib/src/handles/native/collection_handle_base.dart b/packages/realm_dart/lib/src/handles/native/collection_handle_base.dart
index 4fbd3e235..7342ced4f 100644
--- a/packages/realm_dart/lib/src/handles/native/collection_handle_base.dart
+++ b/packages/realm_dart/lib/src/handles/native/collection_handle_base.dart
@@ -7,18 +7,18 @@ import '../../realm_class.dart';
 import 'list_handle.dart';
 import 'map_handle.dart';
 import 'realm_bindings.dart';
+import 'realm_handle.dart';
 import 'rooted_handle.dart';
 
 abstract class CollectionHandleBase<T extends NativeType> extends RootedHandleBase<T> {
   CollectionHandleBase(super.root, super.pointer, super.size);
 }
-
 void createCollection(Realm realm, RealmValue value, Pointer<realm_list> Function() createList, Pointer<realm_dictionary> Function() createMap) {
   CollectionHandleBase? collectionHandle;
   try {
     switch (value.collectionType) {
       case RealmCollectionType.list:
-        final listHandle = ListHandle(createList(), realm.handle);
+        final listHandle = ListHandle(createList(), realm.handle as RealmHandle);
         collectionHandle = listHandle;
 
         final list = realm.createList<RealmValue>(listHandle, null);
@@ -30,7 +30,7 @@ void createCollection(Realm realm, RealmValue value, Pointer<realm_list> Functio
           list.add(item);
         }
       case RealmCollectionType.map:
-        final mapHandle = MapHandle(createMap(), realm.handle);
+        final mapHandle = MapHandle(createMap(), realm.handle as RealmHandle);
         collectionHandle = mapHandle;
 
         final map = realm.createMap<RealmValue>(mapHandle, null);
diff --git a/packages/realm_dart/lib/src/handles/native/config_handle.dart b/packages/realm_dart/lib/src/handles/native/config_handle.dart
index 1c0365357..6c1134264 100644
--- a/packages/realm_dart/lib/src/handles/native/config_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/config_handle.dart
@@ -4,20 +4,20 @@
 import 'dart:async';
 import 'dart:ffi';
 
-import 'ffi.dart';
-import 'error_handling.dart';
-
 import '../../configuration.dart';
 import '../../migration.dart';
 import '../../realm_class.dart';
-import '../../scheduler.dart';
 import '../../user.dart';
 import 'convert_native.dart';
+import 'error_handling.dart';
+import 'ffi.dart';
 import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_handle.dart';
 import 'realm_library.dart';
+import 'scheduler_handle.dart';
 import 'schema_handle.dart';
+import 'user_handle.dart';
 
 class ConfigHandle extends HandleBase<realm_config> {
   ConfigHandle(Pointer<realm_config> pointer) : super(pointer, 512);
@@ -32,7 +32,7 @@ class ConfigHandle extends HandleBase<realm_config> {
       }
 
       realmLib.realm_config_set_path(configHandle.pointer, config.path.toCharPtr(arena));
-      realmLib.realm_config_set_scheduler(configHandle.pointer, scheduler.handle.pointer);
+      realmLib.realm_config_set_scheduler(configHandle.pointer, schedulerHandle.pointer);
 
       if (config.fifoFilesFallbackPath != null) {
         realmLib.realm_config_set_fifo_path(configHandle.pointer, config.fifoFilesFallbackPath!.toCharPtr(arena));
@@ -87,19 +87,19 @@ class ConfigHandle extends HandleBase<realm_config> {
         realmLib.realm_config_set_in_memory(configHandle.pointer, true);
       } else if (config is FlexibleSyncConfiguration) {
         realmLib.realm_config_set_schema_mode(configHandle.pointer, realm_schema_mode.RLM_SCHEMA_MODE_ADDITIVE_DISCOVERED);
-        final syncConfigPtr = realmLib.realm_flx_sync_config_new(config.user.handle.pointer).raiseLastErrorIfNull();
+        final syncConfigPtr = realmLib.realm_flx_sync_config_new((config.user.handle as UserHandle).pointer).raiseLastErrorIfNull();
         try {
           realmLib.realm_sync_config_set_session_stop_policy(syncConfigPtr, config.sessionStopPolicy.index);
           realmLib.realm_sync_config_set_resync_mode(syncConfigPtr, config.clientResetHandler.clientResyncMode.index);
           final errorHandlerCallback =
               Pointer.fromFunction<Void Function(Handle, Pointer<realm_sync_session_t>, realm_sync_error_t)>(_syncErrorHandlerCallback);
-          final errorHandlerUserdata = realmLib.realm_dart_userdata_async_new(config, errorHandlerCallback.cast(), scheduler.handle.pointer);
+          final errorHandlerUserdata = realmLib.realm_dart_userdata_async_new(config, errorHandlerCallback.cast(), schedulerHandle.pointer);
           realmLib.realm_sync_config_set_error_handler(syncConfigPtr, realmLib.addresses.realm_dart_sync_error_handler_callback, errorHandlerUserdata.cast(),
               realmLib.addresses.realm_dart_userdata_async_free);
 
           if (config.clientResetHandler.onBeforeReset != null) {
             final syncBeforeResetCallback = Pointer.fromFunction<Void Function(Handle, Pointer<shared_realm>, Pointer<Void>)>(_syncBeforeResetCallback);
-            final beforeResetUserdata = realmLib.realm_dart_userdata_async_new(config, syncBeforeResetCallback.cast(), scheduler.handle.pointer);
+            final beforeResetUserdata = realmLib.realm_dart_userdata_async_new(config, syncBeforeResetCallback.cast(), schedulerHandle.pointer);
 
             realmLib.realm_sync_config_set_before_client_reset_handler(syncConfigPtr, realmLib.addresses.realm_dart_sync_before_reset_handler_callback,
                 beforeResetUserdata.cast(), realmLib.addresses.realm_dart_userdata_async_free);
@@ -109,7 +109,7 @@ class ConfigHandle extends HandleBase<realm_config> {
             final syncAfterResetCallback =
                 Pointer.fromFunction<Void Function(Handle, Pointer<shared_realm>, Pointer<realm_thread_safe_reference>, Bool, Pointer<Void>)>(
                     _syncAfterResetCallback);
-            final afterResetUserdata = realmLib.realm_dart_userdata_async_new(config, syncAfterResetCallback.cast(), scheduler.handle.pointer);
+            final afterResetUserdata = realmLib.realm_dart_userdata_async_new(config, syncAfterResetCallback.cast(), schedulerHandle.pointer);
 
             realmLib.realm_sync_config_set_after_client_reset_handler(syncConfigPtr, realmLib.addresses.realm_dart_sync_after_reset_handler_callback,
                 afterResetUserdata.cast(), realmLib.addresses.realm_dart_userdata_async_free);
@@ -163,7 +163,7 @@ void _syncAfterResetCallback(Object userdata, Pointer<shared_realm> beforeHandle
         syncConfig,
         RealmHandle.unowned(realmLib.realm_from_thread_safe_reference(
           afterReference,
-          scheduler.handle.pointer,
+          schedulerHandle.pointer,
         )));
 
     try {
diff --git a/packages/realm_dart/lib/src/handles/native/from_native.dart b/packages/realm_dart/lib/src/handles/native/from_native.dart
index d6ab87d4b..7f2c34c7a 100644
--- a/packages/realm_dart/lib/src/handles/native/from_native.dart
+++ b/packages/realm_dart/lib/src/handles/native/from_native.dart
@@ -13,6 +13,7 @@ import 'decimal128.dart';
 import 'list_handle.dart';
 import 'map_handle.dart';
 import 'realm_bindings.dart';
+import 'realm_handle.dart';
 import 'realm_library.dart';
 
 // TODO: Duplicated in to_native.dart
@@ -64,14 +65,14 @@ extension RealmValueEx on realm_value_t {
           throw RealmException('toDartValue called with a list argument but without a list getter');
         }
 
-        final listHandle = ListHandle(getList(), realm.handle);
+        final listHandle = ListHandle(getList(), realm.handle as RealmHandle);
         return realm.createList<RealmValue>(listHandle, null);
       case realm_value_type.RLM_TYPE_DICTIONARY:
         if (getMap == null || realm == null) {
           throw RealmException('toDartValue called with a list argument but without a list getter');
         }
 
-        final mapHandle = MapHandle(getMap(), realm.handle);
+        final mapHandle = MapHandle(getMap(), realm.handle as RealmHandle);
         return realm.createMap<RealmValue>(mapHandle, null);
       default:
         throw RealmException("realm_value_type $type not supported");
diff --git a/packages/realm_dart/lib/src/handles/native/handle_base.dart b/packages/realm_dart/lib/src/handles/native/handle_base.dart
index 93bdadf95..0835503e8 100644
--- a/packages/realm_dart/lib/src/handles/native/handle_base.dart
+++ b/packages/realm_dart/lib/src/handles/native/handle_base.dart
@@ -3,9 +3,13 @@
 
 import 'dart:ffi';
 
+import 'package:realm_dart/realm.dart';
+
 import 'error_handling.dart';
 import 'realm_library.dart';
 
+import '../handle_base.dart' as intf;
+
 // Flag to enable trace on finalization.
 //
 // Be aware that the trace is likely late, and it might in rare case be missing,
@@ -32,33 +36,42 @@ void _tearDownFinalizationTrace(Object value, Object finalizationToken) {
   _traceFinalization(finalizationToken);
 }
 
-abstract class HandleBase<T extends NativeType> implements Finalizable {
+abstract class HandleBase<T extends NativeType> implements Finalizable, intf.HandleBase {
   late Pointer<Void> _finalizableHandle;
-  Pointer<T> pointer;
-  bool get released => pointer == nullptr;
+  Pointer<T> _pointer;
+  Pointer<T> get pointer {
+    if (released) throw RealmError('Trying to access a released handle');
+    return _pointer;
+  }
+
+  @override
+  bool get released => _pointer == nullptr;
+  @override
   final bool isUnowned;
 
-  HandleBase(this.pointer, int size) : isUnowned = false {
-    pointer.raiseLastErrorIfNull();
+  HandleBase(this._pointer, int size) : isUnowned = false {
+    _pointer.raiseLastErrorIfNull();
     _finalizableHandle = realmLib.realm_attach_finalizer(this, pointer.cast(), size);
 
     if (_enableFinalizerTrace) {
-      _setupFinalizationTrace(this, pointer);
+      _setupFinalizationTrace(this, _pointer);
     }
   }
 
-  HandleBase.unowned(this.pointer) : isUnowned = true {
-    pointer.raiseLastErrorIfNull();
+  HandleBase.unowned(this._pointer) : isUnowned = true {
+    _pointer.raiseLastErrorIfNull();
   }
 
   @override
-  String toString() => "${pointer.toString()} value=${pointer.cast<IntPtr>().value}${isUnowned ? ' (unowned)' : ''}";
+  String toString() => "${_pointer.toString()} value=${_pointer.cast<IntPtr>().value}${isUnowned ? ' (unowned)' : ''}";
 
   /// @nodoc
   /// A method that will be invoked just before the handle is released. Allows to cleanup
   /// any custom data that inheritors are storing.
+  @override
   void releaseCore() {}
 
+  @override
   void release() {
     if (released) {
       return;
@@ -69,21 +82,21 @@ abstract class HandleBase<T extends NativeType> implements Finalizable {
     if (!isUnowned) {
       realmLib.realm_detach_finalizer(_finalizableHandle, this);
 
-      realmLib.realm_release(pointer.cast());
+      realmLib.realm_release(_pointer.cast());
     }
 
-    pointer = nullptr;
+    _pointer = nullptr;
 
     if (_enableFinalizerTrace) {
-      _tearDownFinalizationTrace(this, pointer);
+      _tearDownFinalizationTrace(this, _pointer);
     }
   }
 
   @override
   // ignore: hash_and_equals
   bool operator ==(Object other) => other is HandleBase<T>
-      ? pointer == other.pointer
+      ? _pointer == other._pointer
           ? true
-          : realmLib.realm_equals(pointer.cast(), other.pointer.cast())
+          : realmLib.realm_equals(_pointer.cast(), other._pointer.cast())
       : false;
 }
diff --git a/packages/realm_dart/lib/src/handles/native/http_transport_handle.dart b/packages/realm_dart/lib/src/handles/native/http_transport_handle.dart
index c7988f4d2..bf4f4fec5 100644
--- a/packages/realm_dart/lib/src/handles/native/http_transport_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/http_transport_handle.dart
@@ -7,19 +7,19 @@ import 'dart:io';
 
 import '../../logging.dart';
 import '../../realm_dart.dart';
-import '../../scheduler.dart';
 import 'convert_native.dart';
 import 'ffi.dart';
 import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
+import 'scheduler_handle.dart';
 
 class HttpTransportHandle extends HandleBase<realm_http_transport> {
   HttpTransportHandle(Pointer<realm_http_transport> pointer) : super(pointer, 24);
 
   factory HttpTransportHandle.from(HttpClient httpClient) {
     final requestCallback = Pointer.fromFunction<Void Function(Handle, realm_http_request, Pointer<Void>)>(_requestCallback);
-    final requestCallbackUserdata = realmLib.realm_dart_userdata_async_new(httpClient, requestCallback.cast(), scheduler.handle.pointer);
+    final requestCallbackUserdata = realmLib.realm_dart_userdata_async_new(httpClient, requestCallback.cast(), schedulerHandle.pointer);
     return HttpTransportHandle(realmLib.realm_http_transport_new(
       realmLib.addresses.realm_dart_http_request_callback,
       requestCallbackUserdata.cast(),
diff --git a/packages/realm_dart/lib/src/handles/native/list_handle.dart b/packages/realm_dart/lib/src/handles/native/list_handle.dart
index 4c1d330ca..222710e17 100644
--- a/packages/realm_dart/lib/src/handles/native/list_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/list_handle.dart
@@ -16,15 +16,20 @@ import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'results_handle.dart';
 
-class ListHandle extends CollectionHandleBase<realm_list> {
+import '../list_handle.dart' as intf;
+
+class ListHandle extends CollectionHandleBase<realm_list> implements intf.ListHandle {
   ListHandle(Pointer<realm_list> pointer, RealmHandle root) : super(root, pointer, 88);
 
+  @override
   bool get isValid => realmLib.realm_list_is_valid(pointer);
 
+  @override
   ResultsHandle asResults() {
     return ResultsHandle(realmLib.realm_list_to_results(pointer), root);
   }
 
+  @override
   int get size {
     return using((arena) {
       final size = arena<Size>();
@@ -33,18 +38,22 @@ class ListHandle extends CollectionHandleBase<realm_list> {
     });
   }
 
+  @override
   void removeAt(int index) {
     realmLib.realm_list_erase(pointer, index).raiseLastErrorIfFalse();
   }
 
+  @override
   void move(int from, int to) {
     realmLib.realm_list_move(pointer, from, to).raiseLastErrorIfFalse();
   }
 
+  @override
   void deleteAll() {
     realmLib.realm_list_remove_all(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   int indexOf(Object? value) {
     return using((arena) {
       final outIndex = arena<Size>();
@@ -64,11 +73,12 @@ class ListHandle extends CollectionHandleBase<realm_list> {
     });
   }
 
+  @override
   void clear() {
     realmLib.realm_list_clear(pointer).raiseLastErrorIfFalse();
   }
 
-  // TODO: avoid taking the [realm] parameter
+  @override
   Object? elementAt(Realm realm, int index) {
     return using((arena) {
       final realmValue = arena<realm_value_t>();
@@ -81,7 +91,8 @@ class ListHandle extends CollectionHandleBase<realm_list> {
     });
   }
 
-  ListHandle? resolveIn(RealmHandle frozenRealm) {
+  @override
+  ListHandle? resolveIn(covariant RealmHandle frozenRealm) {
     return using((arena) {
       final resultPtr = arena<Pointer<realm_list>>();
       realmLib.realm_list_resolve_in(pointer, frozenRealm.pointer, resultPtr).raiseLastErrorIfFalse();
@@ -90,6 +101,7 @@ class ListHandle extends CollectionHandleBase<realm_list> {
   }
 
   // TODO: Consider splitting into two methods
+  @override
   void addOrUpdateAt(int index, Object? value, bool insert) {
     using((arena) {
       final realmValue = value.toNative(arena);
@@ -97,20 +109,23 @@ class ListHandle extends CollectionHandleBase<realm_list> {
     });
   }
 
-  // TODO: avoid taking the [realm] parameter
+  @override
   void addOrUpdateCollectionAt(Realm realm, int index, RealmValue value, bool insert) {
     createCollection(realm, value, () => (insert ? realmLib.realm_list_insert_list : realmLib.realm_list_set_list)(pointer, index),
         () => (insert ? realmLib.realm_list_insert_dictionary : realmLib.realm_list_set_dictionary)(pointer, index));
   }
 
+  @override
   ObjectHandle setEmbeddedAt(int index) {
     return ObjectHandle(realmLib.realm_list_set_embedded(pointer, index), root);
   }
 
+  @override
   ObjectHandle insertEmbeddedAt(int index) {
     return ObjectHandle(realmLib.realm_list_insert_embedded(pointer, index), root);
   }
 
+  @override
   ResultsHandle query(String query, List<Object?> args) {
     return using((arena) {
       final length = args.length;
@@ -131,6 +146,7 @@ class ListHandle extends CollectionHandleBase<realm_list> {
     });
   }
 
+  @override
   NotificationTokenHandle subscribeForNotifications(NotificationsController controller) {
     return NotificationTokenHandle(
       realmLib.realm_list_add_notification_callback(
diff --git a/packages/realm_dart/lib/src/handles/native/map_changes_handle.dart b/packages/realm_dart/lib/src/handles/native/map_changes_handle.dart
index 4ba4b1f81..98d695f5a 100644
--- a/packages/realm_dart/lib/src/handles/native/map_changes_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/map_changes_handle.dart
@@ -10,9 +10,12 @@ import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
 
-class MapChangesHandle extends HandleBase<realm_dictionary_changes> {
+import '../map_changes_handle.dart' as intf;
+
+class MapChangesHandle extends HandleBase<realm_dictionary_changes> implements intf.MapChangesHandle {
   MapChangesHandle(Pointer<realm_dictionary_changes> pointer) : super(pointer, 256);
 
+  @override
   MapChanges get changes {
     return using((arena) {
       final outNumDeletions = arena<Size>();
diff --git a/packages/realm_dart/lib/src/handles/native/map_handle.dart b/packages/realm_dart/lib/src/handles/native/map_handle.dart
index 5453de7bb..0a3877dd2 100644
--- a/packages/realm_dart/lib/src/handles/native/map_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/map_handle.dart
@@ -17,9 +17,12 @@ import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'results_handle.dart';
 
-class MapHandle extends CollectionHandleBase<realm_dictionary> {
+import '../map_handle.dart' as intf;
+
+class MapHandle extends CollectionHandleBase<realm_dictionary> implements intf.MapHandle {
   MapHandle(Pointer<realm_dictionary> pointer, RealmHandle root) : super(root, pointer, 96); // TODO: check size
 
+  @override
   int get size {
     return using((arena) {
       final outSize = arena<Size>();
@@ -28,6 +31,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   bool remove(String key) {
     return using((arena) {
       final keyNative = key.toNative(arena);
@@ -37,7 +41,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
-  // TODO: avoid taking the [realm] parameter
+  @override
   Object? find(Realm realm, String key) {
     return using((arena) {
       final keyNative = key.toNative(arena);
@@ -55,14 +59,17 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   bool get isValid {
     return realmLib.realm_dictionary_is_valid(pointer);
   }
 
+  @override
   void clear() {
     realmLib.realm_dictionary_clear(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   ResultsHandle get keys {
     return using((arena) {
       final outSize = arena<Size>();
@@ -72,10 +79,12 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   ResultsHandle get values {
     return ResultsHandle(realmLib.realm_dictionary_to_results(pointer), root);
   }
 
+  @override
   bool containsKey(String key) {
     return using((arena) {
       final keyNative = key.toNative(arena);
@@ -85,6 +94,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   int indexOf(Object? value) {
     return using((arena) {
       // TODO: how should this behave for collections
@@ -95,8 +105,10 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   bool containsValue(Object? value) => indexOf(value) > -1;
 
+  @override
   ObjectHandle insertEmbedded(String key) {
     return using((arena) {
       final keyNative = key.toNative(arena);
@@ -104,6 +116,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   void insert(String key, Object? value) {
     using((arena) {
       final keyNative = key.toNative(arena);
@@ -120,6 +133,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   void insertCollection(Realm realm, String key, RealmValue value) {
     using((arena) {
       final keyNative = key.toNative(arena);
@@ -132,6 +146,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   ResultsHandle query(String query, List<Object?> args) {
     return using((arena) {
       final length = args.length;
@@ -153,7 +168,8 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
-  MapHandle? resolveIn(RealmHandle frozenRealm) {
+  @override
+  MapHandle? resolveIn(covariant RealmHandle frozenRealm) {
     return using((arena) {
       final resultPtr = arena<Pointer<realm_dictionary>>();
       realmLib.realm_dictionary_resolve_in(pointer, frozenRealm.pointer, resultPtr).raiseLastErrorIfFalse();
@@ -161,6 +177,7 @@ class MapHandle extends CollectionHandleBase<realm_dictionary> {
     });
   }
 
+  @override
   NotificationTokenHandle subscribeForNotifications(NotificationsController controller) {
     return NotificationTokenHandle(
       realmLib.realm_dictionary_add_notification_callback(
diff --git a/packages/realm_dart/lib/src/handles/native/mutable_subscription_set_handle.dart b/packages/realm_dart/lib/src/handles/native/mutable_subscription_set_handle.dart
index 16f5fd9ff..f78264362 100644
--- a/packages/realm_dart/lib/src/handles/native/mutable_subscription_set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/mutable_subscription_set_handle.dart
@@ -15,14 +15,18 @@ import 'results_handle.dart';
 import 'subscription_handle.dart';
 import 'subscription_set_handle.dart';
 
-class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
+import '../mutable_subscription_set_handle.dart' as intf;
+
+class MutableSubscriptionSetHandle extends SubscriptionSetHandle implements intf.MutableSubscriptionSetHandle {
   MutableSubscriptionSetHandle(Pointer<realm_flx_sync_mutable_subscription_set> pointer, RealmHandle root) : super(pointer.cast(), root);
 
   Pointer<realm_flx_sync_mutable_subscription_set> get _mutablePointer => super.pointer.cast();
 
+  @override
   SubscriptionSetHandle commit() => SubscriptionSetHandle(realmLib.realm_sync_subscription_set_commit(_mutablePointer), root);
 
-  SubscriptionHandle insertOrAssignSubscription(ResultsHandle results, String? name, bool update) {
+  @override
+  SubscriptionHandle insertOrAssignSubscription(covariant ResultsHandle results, String? name, bool update) {
     if (!update) {
       if (name != null && findByName(name) != null) {
         throw RealmException('Duplicate subscription with name: $name');
@@ -44,7 +48,8 @@ class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
     });
   }
 
-  bool erase(SubscriptionHandle subscription) {
+  @override
+  bool erase(covariant SubscriptionHandle subscription) {
     return using((arena) {
       final outErased = arena<Bool>();
       realmLib
@@ -58,6 +63,7 @@ class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
     });
   }
 
+  @override
   bool eraseByName(String name) {
     return using((arena) {
       final outErased = arena<Bool>();
@@ -72,7 +78,8 @@ class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
     });
   }
 
-  bool eraseByResults(ResultsHandle results) {
+  @override
+  bool eraseByResults(covariant ResultsHandle results) {
     return using((arena) {
       final outErased = arena<Bool>();
       realmLib
@@ -86,5 +93,11 @@ class MutableSubscriptionSetHandle extends SubscriptionSetHandle {
     });
   }
 
+  @override
   void clear() => realmLib.realm_sync_subscription_set_clear(_mutablePointer).raiseLastErrorIfFalse();
+
+  @override
+  // Workaround for weird compiler bug
+  // ignore: unnecessary_overrides
+  SubscriptionHandle? findByResults(covariant ResultsHandle results) => super.findByResults(results);
 }
diff --git a/packages/realm_dart/lib/src/handles/native/notification_token_handle.dart b/packages/realm_dart/lib/src/handles/native/notification_token_handle.dart
index d72f36676..55a7e7cc4 100644
--- a/packages/realm_dart/lib/src/handles/native/notification_token_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/notification_token_handle.dart
@@ -8,7 +8,9 @@ import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'rooted_handle.dart';
 
-class NotificationTokenHandle extends RootedHandleBase<realm_notification_token> {
+import '../notification_token_handle.dart' as intf;
+
+class NotificationTokenHandle extends RootedHandleBase<realm_notification_token> implements intf.NotificationTokenHandle {
   NotificationTokenHandle(Pointer<realm_notification_token> pointer, RealmHandle root) : super(root, pointer, 32);
 }
 
diff --git a/packages/realm_dart/lib/src/handles/native/object_changes_handle.dart b/packages/realm_dart/lib/src/handles/native/object_changes_handle.dart
new file mode 100644
index 000000000..54e183a4c
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/native/object_changes_handle.dart
@@ -0,0 +1,32 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'dart:ffi';
+
+import 'ffi.dart';
+import 'handle_base.dart';
+import 'realm_bindings.dart';
+import 'realm_library.dart';
+
+import '../object_changes_handle.dart' as intf;
+
+class ObjectChangesHandle extends HandleBase<realm_object_changes> implements intf.ObjectChangesHandle {
+  ObjectChangesHandle(Pointer<realm_object_changes> pointer) : super(pointer, 256);
+
+  @override
+  bool get isDeleted {
+    return realmLib.realm_object_changes_is_deleted(pointer);
+  }
+
+  @override
+  List<int> get properties {
+    return using((arena) {
+      final count = realmLib.realm_object_changes_get_num_modified_properties(pointer);
+
+      final outModified = arena<realm_property_key_t>(count);
+      realmLib.realm_object_changes_get_modified_properties(pointer, outModified, count);
+
+      return outModified.asTypedList(count).toList();
+    });
+  }
+}
diff --git a/packages/realm_dart/lib/src/handles/native/object_handle.dart b/packages/realm_dart/lib/src/handles/native/object_handle.dart
index 019e85c9e..ecc6e0eed 100644
--- a/packages/realm_dart/lib/src/handles/native/object_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/object_handle.dart
@@ -1,6 +1,8 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
+// ignore_for_file: annotate_overrides
+
 import 'dart:ffi';
 
 import '../../realm_dart.dart';
@@ -8,10 +10,10 @@ import 'collection_handle_base.dart';
 import 'convert_native.dart';
 import 'error_handling.dart';
 import 'ffi.dart';
-import 'handle_base.dart';
 import 'list_handle.dart';
 import 'map_handle.dart';
 import 'notification_token_handle.dart';
+import 'object_changes_handle.dart';
 import 'realm_bindings.dart';
 import 'realm_handle.dart';
 import 'realm_library.dart';
@@ -19,13 +21,17 @@ import 'results_handle.dart';
 import 'rooted_handle.dart';
 import 'set_handle.dart';
 
-class ObjectHandle extends RootedHandleBase<realm_object> {
+import '../object_handle.dart' as intf;
+
+class ObjectHandle extends RootedHandleBase<realm_object> implements intf.ObjectHandle {
   ObjectHandle(Pointer<realm_object> pointer, RealmHandle root) : super(root, pointer, 112);
 
+  @override
   ObjectHandle createEmbedded(int propertyKey) {
     return ObjectHandle(realmLib.realm_set_embedded(pointer, propertyKey), root);
   }
 
+  @override
   (ObjectHandle, int) get parent {
     return using((arena) {
       final parentPtr = arena<Pointer<realm_object>>();
@@ -38,16 +44,20 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
     });
   }
 
+  @override
   int get classKey => realmLib.realm_object_get_table(pointer);
 
+  @override
   bool get isValid => realmLib.realm_object_is_valid(pointer);
 
+  @override
   Link get asLink {
     final realmLink = realmLib.realm_object_as_link(pointer);
     return Link(realmLink);
   }
 
   // TODO: avoid taking the [realm] parameter
+  @override
   Object? getValue(Realm realm, int propertyKey) {
     return using((arena) {
       final realmValue = arena<realm_value_t>();
@@ -62,6 +72,7 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
 
   // TODO: value should be RealmValue, and perhaps this method should be combined
   // with setCollection?
+  @override
   void setValue(int propertyKey, Object? value, bool isDefault) {
     using((arena) {
       final realmValue = value.toNative(arena);
@@ -76,22 +87,27 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
     });
   }
 
+  @override
   ListHandle getList(int propertyKey) {
     return ListHandle(realmLib.realm_get_list(pointer, propertyKey), root);
   }
 
+  @override
   SetHandle getSet(int propertyKey) {
     return SetHandle(realmLib.realm_get_set(pointer, propertyKey), root);
   }
 
+  @override
   MapHandle getMap(int propertyKey) {
     return MapHandle(realmLib.realm_get_dictionary(pointer, propertyKey), root);
   }
 
+  @override
   ResultsHandle getBacklinks(int sourceTableKey, int propertyKey) {
     return ResultsHandle(realmLib.realm_get_backlinks(pointer, sourceTableKey, propertyKey), root);
   }
 
+  @override
   void setCollection(Realm realm, int propertyKey, RealmValue value) {
     createCollection(
       realm,
@@ -101,15 +117,17 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
     );
   }
 
+  @override
   String objectToString() {
     return realmLib.realm_object_to_string(pointer).cast<Utf8>().toRealmDartString(freeRealmMemory: true)!;
   }
 
+  @override
   void delete() {
     realmLib.realm_object_delete(pointer).raiseLastErrorIfFalse();
   }
 
-  ObjectHandle? resolveIn(RealmHandle frozenRealm) {
+  ObjectHandle? resolveIn(covariant RealmHandle frozenRealm) {
     return using((arena) {
       final resultPtr = arena<Pointer<realm_object>>();
       realmLib.realm_object_resolve_in(pointer, frozenRealm.pointer, resultPtr).raiseLastErrorIfFalse();
@@ -117,6 +135,7 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
     });
   }
 
+  @override
   NotificationTokenHandle subscribeForNotifications(NotificationsController controller, [List<String>? keyPaths]) {
     return using((arena) {
       final kpNative = buildAndVerifyKeyPath(keyPaths);
@@ -151,16 +170,26 @@ class ObjectHandle extends RootedHandleBase<realm_object> {
     });
   }
 
+  void verifyKeyPath(List<String>? keyPaths) => buildAndVerifyKeyPath(keyPaths);
+
   @override
   // equals handled by HandleBase<T>
   // ignore: hash_and_equals
   int get hashCode => asLink.hash;
 }
 
-extension type Link(realm_link_t link) {
+class Link implements intf.Link {
+  final realm_link link;
+
+  Link(this.link);
+
+  @override
   int get targetKey => link.target;
+
+  @override
   int get classKey => link.target_table;
 
+  @override
   int get hash => Object.hash(targetKey, classKey);
 }
 
@@ -185,22 +214,3 @@ void _objectChangeCallback(Pointer<Void> userdata, Pointer<realm_object_changes>
     controller.onError(RealmError("Error handling change notifications. Error: $e"));
   }
 }
-
-class ObjectChangesHandle extends HandleBase<realm_object_changes> {
-  ObjectChangesHandle(Pointer<realm_object_changes> pointer) : super(pointer, 256);
-
-  bool get isDeleted {
-    return realmLib.realm_object_changes_is_deleted(pointer);
-  }
-
-  List<int> get properties {
-    return using((arena) {
-      final count = realmLib.realm_object_changes_get_num_modified_properties(pointer);
-
-      final outModified = arena<realm_property_key_t>(count);
-      realmLib.realm_object_changes_get_modified_properties(pointer, outModified, count);
-
-      return outModified.asTypedList(count).toList();
-    });
-  }
-}
diff --git a/packages/realm_dart/lib/src/handles/native/realm_handle.dart b/packages/realm_dart/lib/src/handles/native/realm_handle.dart
index 8f63fd6b1..7bfb1b2c0 100644
--- a/packages/realm_dart/lib/src/handles/native/realm_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/realm_handle.dart
@@ -25,7 +25,9 @@ import 'schema_handle.dart';
 import 'session_handle.dart';
 import 'subscription_set_handle.dart';
 
-class RealmHandle extends HandleBase<shared_realm> {
+import '../realm_handle.dart' as intf;
+
+class RealmHandle extends HandleBase<shared_realm> implements intf.RealmHandle {
   int _counter = 0;
 
   final Map<int, WeakReference<RootedHandleBase>> _children = {};
@@ -41,13 +43,15 @@ class RealmHandle extends HandleBase<shared_realm> {
         .raiseLastErrorIfNull());
   }
 
-  int addChild(RootedHandleBase child) {
+  @override
+  int addChild(covariant RootedHandleBase child) {
     final id = _counter++;
     _children[id] = WeakReference(child);
     rootedHandleFinalizer.attach(this, FinalizationToken(this, id), detach: this);
     return id;
   }
 
+  @override
   void removeChild(int id) {
     final child = _children.remove(id);
     if (child != null) {
@@ -65,6 +69,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     }
   }
 
+  @override
   ObjectHandle createWithPrimaryKey(int classKey, Object? primaryKey) {
     return using((arena) {
       final realmValue = primaryKey.toNative(arena);
@@ -72,10 +77,12 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   ObjectHandle create(int classKey) {
     return ObjectHandle(realmLib.realm_object_create(pointer, classKey), this);
   }
 
+  @override
   ObjectHandle getOrCreateWithPrimaryKey(int classKey, Object? primaryKey) {
     return using((arena) {
       final realmValue = primaryKey.toNative(arena);
@@ -92,6 +99,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   bool compact() {
     return using((arena) {
       final outDidCompact = arena<Bool>();
@@ -100,11 +108,13 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   void writeCopy(Configuration config) {
     final configHandle = ConfigHandle.from(config);
     realmLib.realm_convert_with_config(pointer, configHandle.pointer, false).raiseLastErrorIfFalse();
   }
 
+  @override
   ResultsHandle queryClass(int classKey, String query, List<Object?> args) {
     return using((arena) {
       final length = args.length;
@@ -126,40 +136,50 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   RealmHandle freeze() => RealmHandle(realmLib.realm_freeze(pointer));
 
+  @override
   SessionHandle getSession() {
     return SessionHandle(realmLib.realm_sync_session_get(pointer), this);
   }
 
+  @override
   bool get isFrozen {
     return realmLib.realm_is_frozen(pointer.cast());
   }
 
+  @override
   SubscriptionSetHandle get subscriptions {
     return SubscriptionSetHandle(realmLib.realm_sync_get_active_subscription_set(pointer), this);
   }
 
+  @override
   void disableAutoRefreshForTesting() {
     realmLib.realm_set_auto_refresh(pointer, false);
   }
 
+  @override
   void close() {
     realmLib.realm_close(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   bool get isClosed {
     return realmLib.realm_is_closed(pointer);
   }
 
+  @override
   void beginWrite() {
     realmLib.realm_begin_write(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   void commitWrite() {
     realmLib.realm_commit(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   Future<void> beginWriteAsync(CancellationToken? ct) {
     int? id;
     final completer = CancellableCompleter<void>(ct, onCancel: () {
@@ -186,6 +206,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     return completer.future;
   }
 
+  @override
   Future<void> commitWriteAsync(CancellationToken? ct) {
     int? id;
     final completer = CancellableCompleter<void>(ct, onCancel: () {
@@ -250,6 +271,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   Future<bool> refreshAsync() async {
     final completer = Completer<bool>();
     final callback = Pointer.fromFunction<Void Function(Pointer<Void>)>(_realmRefreshAsyncCallback);
@@ -271,10 +293,12 @@ class RealmHandle extends HandleBase<shared_realm> {
     completer.complete(true);
   }
 
+  @override
   ResultsHandle findAll(int classKey) {
     return ResultsHandle(realmLib.realm_object_find_all(pointer, classKey), this);
   }
 
+  @override
   ObjectHandle? find(int classKey, Object? primaryKey) {
     return using((arena) {
       final realmValue = primaryKey.toNative(arena);
@@ -288,12 +312,14 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
-  ObjectHandle? findExisting(int classKey, ObjectHandle other) {
+  @override
+  ObjectHandle? findExisting(int classKey, covariant ObjectHandle other) {
     final key = realmLib.realm_object_get_key(other.pointer);
     return ObjectHandle(realmLib.realm_get_object(pointer, classKey, key), this);
   }
 
-  void renameProperty(String objectType, String oldName, String newName, SchemaHandle schema) {
+  @override
+  void renameProperty(String objectType, String oldName, String newName, covariant SchemaHandle schema) {
     using((arena) {
       realmLib
           .realm_schema_rename_property(
@@ -307,6 +333,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   bool deleteType(String objectType) {
     return using((arena) {
       final tableDeleted = arena<Bool>();
@@ -315,10 +342,12 @@ class RealmHandle extends HandleBase<shared_realm> {
     });
   }
 
+  @override
   ObjectHandle getObject(int classKey, int objectKey) {
     return ObjectHandle(realmLib.realm_get_object(pointer, classKey, objectKey), this);
   }
 
+  @override
   CallbackTokenHandle subscribeForSchemaNotifications(Realm realm) {
     return CallbackTokenHandle(
       realmLib.realm_add_schema_changed_callback(
@@ -331,6 +360,7 @@ class RealmHandle extends HandleBase<shared_realm> {
     );
   }
 
+  @override
   RealmSchema readSchema() {
     return using((arena) {
       return _readSchema(arena);
@@ -397,12 +427,14 @@ class RealmHandle extends HandleBase<shared_realm> {
     return SchemaObject(baseType, type, name, result);
   }
 
+  @override
   Map<String, RealmPropertyMetadata> getPropertiesMetadata(int classKey, String? primaryKeyName) {
     return using((arena) {
       return _getPropertiesMetadata(classKey, primaryKeyName, arena);
     });
   }
 
+  @override
   RealmObjectMetadata getObjectMetadata(SchemaObject schema) {
     return using((arena) {
       final found = arena<Bool>();
@@ -438,7 +470,7 @@ class RealmHandle extends HandleBase<shared_realm> {
   }
 }
 
-class CallbackTokenHandle extends RootedHandleBase<realm_callback_token> {
+class CallbackTokenHandle extends RootedHandleBase<realm_callback_token> implements intf.CallbackTokenHandle {
   CallbackTokenHandle(Pointer<realm_callback_token> pointer, RealmHandle root) : super(root, pointer, 32);
 }
 
diff --git a/packages/realm_dart/lib/src/handles/native/results_handle.dart b/packages/realm_dart/lib/src/handles/native/results_handle.dart
index 9fa5c1ab6..43c32a06f 100644
--- a/packages/realm_dart/lib/src/handles/native/results_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/results_handle.dart
@@ -16,9 +16,12 @@ import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'rooted_handle.dart';
 
-class ResultsHandle extends RootedHandleBase<realm_results> {
+import '../results_handle.dart' as intf;
+
+class ResultsHandle extends RootedHandleBase<realm_results> implements intf.ResultsHandle {
   ResultsHandle(Pointer<realm_results> pointer, RealmHandle root) : super(root, pointer, 872);
 
+  @override
   ResultsHandle queryResults(String query, List<Object> args) {
     return using((arena) {
       final length = args.length;
@@ -39,6 +42,7 @@ class ResultsHandle extends RootedHandleBase<realm_results> {
     });
   }
 
+  @override
   int find(Object? value) {
     return using((arena) {
       final outIndex = arena<Size>();
@@ -58,10 +62,12 @@ class ResultsHandle extends RootedHandleBase<realm_results> {
     });
   }
 
+  @override
   ObjectHandle getObjectAt(int index) {
     return ObjectHandle(realmLib.realm_results_get_object(pointer, index), root);
   }
 
+  @override
   int get count {
     return using((arena) {
       final countPtr = arena<Size>();
@@ -70,6 +76,7 @@ class ResultsHandle extends RootedHandleBase<realm_results> {
     });
   }
 
+  @override
   bool isValid() {
     return using((arena) {
       final isValid = arena<Bool>();
@@ -78,18 +85,22 @@ class ResultsHandle extends RootedHandleBase<realm_results> {
     });
   }
 
+  @override
   void deleteAll() {
     realmLib.realm_results_delete_all(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   ResultsHandle snapshot() {
     return ResultsHandle(realmLib.realm_results_snapshot(pointer), root);
   }
 
-  ResultsHandle resolveIn(RealmHandle realmHandle) {
+  @override
+  ResultsHandle resolveIn(covariant RealmHandle realmHandle) {
     return ResultsHandle(realmLib.realm_results_resolve_in(pointer, realmHandle.pointer), realmHandle);
   }
 
+  @override
   Object? elementAt(Realm realm, int index) {
     return using((arena) {
       final realmValue = arena<realm_value_t>();
@@ -102,6 +113,7 @@ class ResultsHandle extends RootedHandleBase<realm_results> {
     });
   }
 
+  @override
   NotificationTokenHandle subscribeForNotifications(NotificationsController controller) {
     return NotificationTokenHandle(
       realmLib.realm_results_add_notification_callback(
diff --git a/packages/realm_dart/lib/src/handles/native/scheduler_handle.dart b/packages/realm_dart/lib/src/handles/native/scheduler_handle.dart
index 4ad210542..c408943bc 100644
--- a/packages/realm_dart/lib/src/handles/native/scheduler_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/scheduler_handle.dart
@@ -3,11 +3,14 @@
 
 import 'dart:ffi';
 
+import '../../scheduler.dart';
 import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
 
-class SchedulerHandle extends HandleBase<realm_scheduler> {
+import '../scheduler_handle.dart' as intf;
+
+class SchedulerHandle extends HandleBase<realm_scheduler> implements intf.SchedulerHandle {
   SchedulerHandle._(Pointer<realm_scheduler> pointer) : super(pointer, 24);
 
   factory SchedulerHandle(int isolateId, int sendPort) {
@@ -15,8 +18,13 @@ class SchedulerHandle extends HandleBase<realm_scheduler> {
     return SchedulerHandle._(schedulerPtr);
   }
 
+  @override
   void invoke(int workQueue) {
     final queuePointer = Pointer<realm_work_queue>.fromAddress(workQueue);
     realmLib.realm_scheduler_perform_work(queuePointer);
   }
 }
+
+final schedulerHandle = scheduler.handle as SchedulerHandle;
+
+
diff --git a/packages/realm_dart/lib/src/handles/native/schema_handle.dart b/packages/realm_dart/lib/src/handles/native/schema_handle.dart
index 7143cb1b8..00a4896b4 100644
--- a/packages/realm_dart/lib/src/handles/native/schema_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/schema_handle.dart
@@ -3,6 +3,8 @@
 
 import 'dart:ffi';
 
+import 'package:realm_dart/src/handles/scheduler_handle.dart';
+
 import 'ffi.dart';
 import 'package:realm_common/realm_common.dart';
 
@@ -12,7 +14,9 @@ import 'realm_bindings.dart';
 import 'realm_library.dart';
 import 'to_native.dart';
 
-class SchemaHandle extends HandleBase<realm_schema> {
+import '../schema_handle.dart' as intf;
+
+class SchemaHandle extends HandleBase<realm_schema> implements intf.SchemaHandle {
   SchemaHandle(Pointer<realm_schema> pointer) : super(pointer, 24);
 
   SchemaHandle.unowned(super.pointer) : super.unowned();
diff --git a/packages/realm_dart/lib/src/handles/native/session_handle.dart b/packages/realm_dart/lib/src/handles/native/session_handle.dart
index e8f20ad23..dcc3415ca 100644
--- a/packages/realm_dart/lib/src/handles/native/session_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/session_handle.dart
@@ -4,38 +4,43 @@
 import 'dart:ffi';
 
 import 'package:cancellation_token/cancellation_token.dart';
-import 'ffi.dart';
 
 import '../../realm_dart.dart';
-import '../../scheduler.dart';
 import '../../session.dart';
+import '../session_handle.dart' as intf;
 import 'convert_native.dart';
+import 'ffi.dart';
 import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'rooted_handle.dart';
+import 'scheduler_handle.dart';
 import 'user_handle.dart';
 
-class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
+class SessionHandle extends RootedHandleBase<realm_sync_session_t> implements intf.SessionHandle {
   @override
   bool get shouldRoot => true;
 
   SessionHandle(Pointer<realm_sync_session_t> pointer, RealmHandle root) : super(root, pointer, 24);
 
+  @override
   String get path {
     return realmLib.realm_sync_session_get_file_path(pointer).cast<Utf8>().toRealmDartString()!;
   }
 
+  @override
   ConnectionState get connectionState {
     final value = realmLib.realm_sync_session_get_connection_state(pointer);
     return ConnectionState.values[value];
   }
 
+  @override
   UserHandle get user {
     return UserHandle(realmLib.realm_sync_session_get_user(pointer));
   }
 
+  @override
   SessionState get state {
     final value = realmLib.realm_sync_session_get_state(pointer);
     return _convertCoreSessionState(value);
@@ -55,14 +60,17 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
     }
   }
 
+  @override
   void pause() {
     realmLib.realm_sync_session_pause(pointer);
   }
 
+  @override
   void resume() {
     realmLib.realm_sync_session_resume(pointer);
   }
 
+  @override
   void raiseError(int errorCode, bool isFatal) {
     using((arena) {
       final message = "Simulated session error".toCharPtr(arena);
@@ -70,11 +78,12 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
     });
   }
 
+  @override
   Future<void> waitForUpload([CancellationToken? cancellationToken]) {
     final completer = CancellableCompleter<void>(cancellationToken);
     if (!completer.isCancelled) {
       final callback = Pointer.fromFunction<Void Function(Handle, Pointer<realm_error_t>)>(_waitCompletionCallback);
-      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), scheduler.handle.pointer);
+      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), schedulerHandle.pointer);
       realmLib.realm_sync_session_wait_for_upload_completion(
         pointer,
         realmLib.addresses.realm_dart_sync_wait_for_completion_callback,
@@ -85,11 +94,12 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
     return completer.future;
   }
 
+  @override
   Future<void> waitForDownload([CancellationToken? cancellationToken]) {
     final completer = CancellableCompleter<void>(cancellationToken);
     if (!completer.isCancelled) {
       final callback = Pointer.fromFunction<Void Function(Handle, Pointer<realm_error_t>)>(_waitCompletionCallback);
-      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), scheduler.handle.pointer);
+      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), schedulerHandle.pointer);
       realmLib.realm_sync_session_wait_for_download_completion(
         pointer,
         realmLib.addresses.realm_dart_sync_wait_for_completion_callback,
@@ -113,9 +123,10 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
     }
   }
 
+  @override
   SyncSessionNotificationTokenHandle subscribeForConnectionStateNotifications(SessionConnectionStateController controller) {
     final callback = Pointer.fromFunction<Void Function(Handle, Int32, Int32)>(_onConnectionStateChange);
-    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), scheduler.handle.pointer);
+    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), schedulerHandle.pointer);
     return SyncSessionNotificationTokenHandle(
       realmLib.realm_sync_session_register_connection_state_change_callback(
         pointer,
@@ -126,6 +137,7 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
     );
   }
 
+  @override
   SyncSessionNotificationTokenHandle subscribeForProgressNotifications(
     ProgressDirection direction,
     ProgressMode mode,
@@ -133,7 +145,7 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
   ) {
     final isStreaming = mode == ProgressMode.reportIndefinitely;
     final callback = Pointer.fromFunction<Void Function(Handle, Uint64, Uint64, Double)>(syncProgressCallback);
-    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), scheduler.handle.pointer);
+    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), schedulerHandle.pointer);
     return SyncSessionNotificationTokenHandle(
       realmLib.realm_sync_session_register_progress_notifier(
         pointer,
@@ -147,7 +159,8 @@ class SessionHandle extends RootedHandleBase<realm_sync_session_t> {
   }
 }
 
-class SyncSessionNotificationTokenHandle extends HandleBase<realm_sync_session_connection_state_notification_token> {
+class SyncSessionNotificationTokenHandle extends HandleBase<realm_sync_session_connection_state_notification_token>
+    implements intf.SyncSessionNotificationTokenHandle {
   SyncSessionNotificationTokenHandle(Pointer<realm_sync_session_connection_state_notification_token> pointer) : super(pointer, 32);
 }
 
diff --git a/packages/realm_dart/lib/src/handles/native/set_handle.dart b/packages/realm_dart/lib/src/handles/native/set_handle.dart
index f0a458d87..0a2de4a01 100644
--- a/packages/realm_dart/lib/src/handles/native/set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/set_handle.dart
@@ -16,13 +16,17 @@ import 'realm_library.dart';
 import 'results_handle.dart';
 import 'rooted_handle.dart';
 
-class SetHandle extends RootedHandleBase<realm_set> {
+import '../set_handle.dart' as intf;
+
+class SetHandle extends RootedHandleBase<realm_set> implements intf.SetHandle {
   SetHandle(Pointer<realm_set> pointer, RealmHandle root) : super(root, pointer, 96);
 
+  @override
   ResultsHandle get asResults {
     return ResultsHandle(realmLib.realm_set_to_results(pointer), root);
   }
 
+  @override
   ResultsHandle query(String query, List<Object?> args) {
     return using((arena) {
       final length = args.length;
@@ -43,6 +47,7 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   bool insert(Object? value) {
     return using((arena) {
       final realmValue = value.toNative(arena);
@@ -54,6 +59,7 @@ class SetHandle extends RootedHandleBase<realm_set> {
   }
 
   // TODO: avoid taking the [realm] parameter
+  @override
   Object? elementAt(Realm realm, int index) {
     return using((arena) {
       final realmValue = arena<realm_value_t>();
@@ -67,6 +73,7 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   bool find(Object? value) {
     return using((arena) {
       // TODO: how should this behave for collections
@@ -78,6 +85,7 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   bool remove(Object? value) {
     return using((arena) {
       // TODO: do we support sets containing mixed collections
@@ -88,10 +96,12 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   void clear() {
     realmLib.realm_set_clear(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   int get size {
     return using((arena) {
       final outSize = arena<Size>();
@@ -100,15 +110,18 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   bool get isValid {
     return realmLib.realm_set_is_valid(pointer);
   }
 
+  @override
   void deleteAll() {
     realmLib.realm_set_remove_all(pointer).raiseLastErrorIfFalse();
   }
 
-  SetHandle? resolveIn(RealmHandle frozenRealm) {
+  @override
+  SetHandle? resolveIn(covariant RealmHandle frozenRealm) {
     return using((arena) {
       final resultPtr = arena<Pointer<realm_set>>();
       realmLib.realm_set_resolve_in(pointer, frozenRealm.pointer, resultPtr).raiseLastErrorIfFalse();
@@ -116,6 +129,7 @@ class SetHandle extends RootedHandleBase<realm_set> {
     });
   }
 
+  @override
   NotificationTokenHandle subscribeForNotifications(NotificationsController controller) {
     return NotificationTokenHandle(
       realmLib.realm_set_add_notification_callback(
diff --git a/packages/realm_dart/lib/src/handles/native/subscription_handle.dart b/packages/realm_dart/lib/src/handles/native/subscription_handle.dart
index e3ffc9d74..b2b6b4fed 100644
--- a/packages/realm_dart/lib/src/handles/native/subscription_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/subscription_handle.dart
@@ -9,20 +9,28 @@ import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
 
-class SubscriptionHandle extends HandleBase<realm_flx_sync_subscription> {
+import '../subscription_handle.dart' as intf;
+class SubscriptionHandle extends HandleBase<realm_flx_sync_subscription> implements intf.SubscriptionHandle{
   SubscriptionHandle(Pointer<realm_flx_sync_subscription> pointer) : super(pointer, 184);
 
+  @override
   ObjectId get id => realmLib.realm_sync_subscription_id(pointer).toDart();
 
+  @override
   String? get name => realmLib.realm_sync_subscription_name(pointer).toDart();
 
+  @override
   String get objectClassName => realmLib.realm_sync_subscription_object_class_name(pointer).toDart()!;
 
+  @override
   String get queryString => realmLib.realm_sync_subscription_query_string(pointer).toDart()!;
 
+  @override
   DateTime get createdAt => realmLib.realm_sync_subscription_created_at(pointer).toDart();
 
+  @override
   DateTime get updatedAt => realmLib.realm_sync_subscription_updated_at(pointer).toDart();
 
-  bool equalTo(SubscriptionHandle other) => realmLib.realm_equals(pointer.cast(), other.pointer.cast());
+  @override
+  bool equalTo(covariant SubscriptionHandle other) => realmLib.realm_equals(pointer.cast(), other.pointer.cast());
 }
diff --git a/packages/realm_dart/lib/src/handles/native/subscription_set_handle.dart b/packages/realm_dart/lib/src/handles/native/subscription_set_handle.dart
index fa1b7883f..271291913 100644
--- a/packages/realm_dart/lib/src/handles/native/subscription_set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/subscription_set_handle.dart
@@ -4,39 +4,44 @@
 import 'dart:ffi';
 
 import 'package:cancellation_token/cancellation_token.dart';
-import 'ffi.dart';
 
 import '../../realm_dart.dart';
-import '../../scheduler.dart';
+import '../subscription_set_handle.dart' as intf;
 import 'convert.dart';
 import 'convert_native.dart';
 import 'error_handling.dart';
+import 'ffi.dart';
 import 'mutable_subscription_set_handle.dart';
 import 'realm_bindings.dart';
 import 'realm_handle.dart';
 import 'realm_library.dart';
 import 'results_handle.dart';
 import 'rooted_handle.dart';
+import 'scheduler_handle.dart';
 import 'subscription_handle.dart';
-
-class SubscriptionSetHandle extends RootedHandleBase<realm_flx_sync_subscription_set> {
+class SubscriptionSetHandle extends RootedHandleBase<realm_flx_sync_subscription_set> implements intf.SubscriptionSetHandle {
   @override
   bool get shouldRoot => true;
 
   SubscriptionSetHandle(Pointer<realm_flx_sync_subscription_set> pointer, RealmHandle root) : super(root, pointer, 128);
 
+  @override
   void refresh() => realmLib.realm_sync_subscription_set_refresh(pointer).raiseLastErrorIfFalse();
 
+  @override
   int get size => realmLib.realm_sync_subscription_set_size(pointer);
 
+  @override
   Exception? get error {
     final error = realmLib.realm_sync_subscription_set_error_str(pointer);
     final message = error.cast<Utf8>().toRealmDartString(treatEmptyAsNull: true);
     return message.convert(RealmException.new);
   }
 
+  @override
   SubscriptionHandle operator [](int index) => SubscriptionHandle(realmLib.realm_sync_subscription_at(pointer, index));
 
+  @override
   SubscriptionHandle? findByName(String name) {
     return using((arena) {
       final result = realmLib.realm_sync_find_subscription_by_name(
@@ -47,7 +52,8 @@ class SubscriptionSetHandle extends RootedHandleBase<realm_flx_sync_subscription
     });
   }
 
-  SubscriptionHandle? findByResults(ResultsHandle results) {
+  @override
+  SubscriptionHandle? findByResults(covariant ResultsHandle results) {
     final result = realmLib.realm_sync_find_subscription_by_results(
       pointer,
       results.pointer,
@@ -55,10 +61,13 @@ class SubscriptionSetHandle extends RootedHandleBase<realm_flx_sync_subscription
     return result.convert(SubscriptionHandle.new);
   }
 
+  @override
   int get version => realmLib.realm_sync_subscription_set_version(pointer);
 
+  @override
   SubscriptionSetState get state => SubscriptionSetState.values[realmLib.realm_sync_subscription_set_state(pointer)];
 
+  @override
   MutableSubscriptionSetHandle toMutable() => MutableSubscriptionSetHandle(realmLib.realm_sync_make_subscription_set_mutable(pointer), root);
 
   static void _stateChangeCallback(Object userdata, int state) {
@@ -68,11 +77,12 @@ class SubscriptionSetHandle extends RootedHandleBase<realm_flx_sync_subscription
     }
   }
 
+  @override
   Future<SubscriptionSetState> waitForStateChange(SubscriptionSetState notifyWhen, [CancellationToken? cancellationToken]) {
     final completer = CancellableCompleter<SubscriptionSetState>(cancellationToken);
     if (!completer.isCancelled) {
       final callback = Pointer.fromFunction<Void Function(Handle, Int32)>(_stateChangeCallback);
-      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), scheduler.handle.pointer);
+      final userdata = realmLib.realm_dart_userdata_async_new(completer, callback.cast(), schedulerHandle.pointer);
       realmLib.realm_sync_on_subscription_set_state_change_async(pointer, notifyWhen.index,
           realmLib.addresses.realm_dart_sync_on_subscription_state_changed_callback, userdata.cast(), realmLib.addresses.realm_dart_userdata_async_free);
     }
diff --git a/packages/realm_dart/lib/src/handles/native/user_handle.dart b/packages/realm_dart/lib/src/handles/native/user_handle.dart
index abacd3c87..ff8e2d0c2 100644
--- a/packages/realm_dart/lib/src/handles/native/user_handle.dart
+++ b/packages/realm_dart/lib/src/handles/native/user_handle.dart
@@ -5,40 +5,44 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:ffi';
 
-import 'ffi.dart';
-
 import '../../credentials.dart';
 import '../../realm_dart.dart';
-import '../../scheduler.dart';
 import '../../user.dart';
+import '../user_handle.dart' as intf;
 import 'app_handle.dart';
 import 'convert.dart';
 import 'convert_native.dart';
 import 'credentials_handle.dart';
 import 'error_handling.dart';
+import 'ffi.dart';
 import 'handle_base.dart';
 import 'realm_bindings.dart';
 import 'realm_library.dart';
+import 'scheduler_handle.dart';
 
-class UserHandle extends HandleBase<realm_user> {
+class UserHandle extends HandleBase<realm_user> implements intf.UserHandle {
   UserHandle(Pointer<realm_user> pointer) : super(pointer, 24);
 
+  @override
   AppHandle get app {
     return realmLib.realm_user_get_app(pointer).convert(AppHandle.new) ??
         (throw RealmException('User does not have an associated app. This is likely due to the user being logged out.'));
   }
 
+  @override
   UserState get state {
     final nativeUserState = realmLib.realm_user_get_state(pointer);
     return UserState.values.fromIndex(nativeUserState);
   }
 
+  @override
   String get id {
     final idPtr = realmLib.realm_user_get_identity(pointer).raiseLastErrorIfNull();
     final userId = idPtr.cast<Utf8>().toDartString();
     return userId;
   }
 
+  @override
   List<UserIdentity> get identities {
     return using((arena) {
       return _userGetIdentities(arena);
@@ -67,31 +71,37 @@ class UserHandle extends HandleBase<realm_user> {
     return result;
   }
 
+  @override
   Future<void> logOut() async {
     realmLib.realm_user_log_out(pointer).raiseLastErrorIfFalse();
   }
 
+  @override
   String? get deviceId {
     final deviceId = realmLib.realm_user_get_device_id(pointer).raiseLastErrorIfNull();
     return deviceId.cast<Utf8>().toRealmDartString(treatEmptyAsNull: true, freeRealmMemory: true);
   }
 
+  @override
   UserProfile get profileData {
     final data = realmLib.realm_user_get_profile_data(pointer).raiseLastErrorIfNull();
     final dynamic profileData = jsonDecode(data.cast<Utf8>().toRealmDartString(freeRealmMemory: true)!);
     return UserProfile(profileData as Map<String, dynamic>);
   }
 
+  @override
   String get refreshToken {
     final token = realmLib.realm_user_get_refresh_token(pointer).raiseLastErrorIfNull();
     return token.cast<Utf8>().toRealmDartString(freeRealmMemory: true)!;
   }
 
+  @override
   String get accessToken {
     final token = realmLib.realm_user_get_access_token(pointer).raiseLastErrorIfNull();
     return token.cast<Utf8>().toRealmDartString(freeRealmMemory: true)!;
   }
 
+  @override
   String get path {
     final syncConfigPtr = realmLib.realm_flx_sync_config_new(pointer).raiseLastErrorIfNull();
     try {
@@ -102,12 +112,14 @@ class UserHandle extends HandleBase<realm_user> {
     }
   }
 
+  @override
   String? get customData {
     final customDataPtr = realmLib.realm_user_get_custom_data(pointer);
     return customDataPtr.cast<Utf8>().toRealmDartString(freeRealmMemory: true, treatEmptyAsNull: true);
   }
 
-  Future<UserHandle> linkCredentials(AppHandle app, CredentialsHandle credentials) {
+  @override
+  Future<UserHandle> linkCredentials(covariant AppHandle app, CredentialsHandle credentials) {
     final completer = Completer<UserHandle>();
     realmLib
         .realm_app_link_user(
@@ -122,7 +134,8 @@ class UserHandle extends HandleBase<realm_user> {
     return completer.future;
   }
 
-  Future<ApiKey> createApiKey(AppHandle app, String name) {
+  @override
+  Future<ApiKey> createApiKey(covariant AppHandle app, String name) {
     return using((arena) {
       final namePtr = name.toCharPtr(arena);
       final completer = Completer<ApiKey>();
@@ -141,7 +154,8 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
-  Future<ApiKey> fetchApiKey(AppHandle app, ObjectId id) {
+  @override
+  Future<ApiKey> fetchApiKey(covariant AppHandle app, ObjectId id) {
     return using((arena) {
       final completer = Completer<ApiKey>();
       final nativeId = id.toNative(arena);
@@ -160,7 +174,8 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
-  Future<List<ApiKey>> fetchAllApiKeys(AppHandle app) {
+  @override
+  Future<List<ApiKey>> fetchAllApiKeys(covariant AppHandle app) {
     return using((arena) {
       final completer = Completer<List<ApiKey>>();
       realmLib
@@ -177,7 +192,8 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
-  Future<void> deleteApiKey(AppHandle app, ObjectId id) {
+  @override
+  Future<void> deleteApiKey(covariant AppHandle app, ObjectId id) {
     return using((arena) {
       final completer = Completer<void>();
       final nativeId = id.toNative(arena);
@@ -196,7 +212,8 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
-  Future<void> disableApiKey(AppHandle app, ObjectId objectId) {
+  @override
+  Future<void> disableApiKey(covariant AppHandle app, ObjectId objectId) {
     return using((arena) {
       final completer = Completer<void>();
       final nativeId = objectId.toNative(arena);
@@ -216,7 +233,8 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
-  Future<void> enableApiKey(AppHandle app, ObjectId objectId) {
+  @override
+  Future<void> enableApiKey(covariant AppHandle app, ObjectId objectId) {
     return using((arena) {
       final completer = Completer<void>();
       final nativeId = objectId.toNative(arena);
@@ -236,9 +254,10 @@ class UserHandle extends HandleBase<realm_user> {
     });
   }
 
+  @override
   UserNotificationTokenHandle subscribeForNotifications(UserNotificationsController controller) {
     final callback = Pointer.fromFunction<Void Function(Handle, Int32)>(_userChangeCallback);
-    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), scheduler.handle.pointer);
+    final userdata = realmLib.realm_dart_userdata_async_new(controller, callback.cast(), schedulerHandle.pointer);
     final notificationToken = realmLib.realm_sync_user_on_state_change_register_callback(
       pointer,
       realmLib.addresses.realm_dart_user_change_callback,
@@ -249,7 +268,7 @@ class UserHandle extends HandleBase<realm_user> {
   }
 }
 
-class UserNotificationTokenHandle extends HandleBase<realm_app_user_subscription_token> {
+class UserNotificationTokenHandle extends HandleBase<realm_app_user_subscription_token> implements intf.UserNotificationTokenHandle {
   UserNotificationTokenHandle(Pointer<realm_app_user_subscription_token> pointer) : super(pointer, 32);
 }
 
@@ -270,7 +289,7 @@ Pointer<Void> createAsyncUserCallbackUserdata(Completer<void> completer) {
   final userdata = realmLib.realm_dart_userdata_async_new(
     completer,
     callback.cast(),
-    scheduler.handle.pointer,
+    schedulerHandle.pointer,
   );
 
   return userdata.cast();
@@ -304,7 +323,7 @@ Pointer<Void> _createAsyncApikeyCallbackUserdata<T extends Function>(Completer<A
   final userdata = realmLib.realm_dart_userdata_async_new(
     completer,
     callback.cast(),
-    scheduler.handle.pointer,
+    schedulerHandle.pointer,
   );
 
   return userdata.cast();
@@ -331,7 +350,7 @@ Pointer<Void> _createAsyncApikeyListCallbackUserdata<T extends Function>(Complet
   final userdata = realmLib.realm_dart_userdata_async_new(
     completer,
     callback.cast(),
-    scheduler.handle.pointer,
+    schedulerHandle.pointer,
   );
 
   return userdata.cast();
diff --git a/packages/realm_dart/lib/src/handles/notification_token_handle.dart b/packages/realm_dart/lib/src/handles/notification_token_handle.dart
index ddca8f3cc..a1698ea02 100644
--- a/packages/realm_dart/lib/src/handles/notification_token_handle.dart
+++ b/packages/realm_dart/lib/src/handles/notification_token_handle.dart
@@ -1,5 +1,6 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/notification_token_handle.dart'
-    if (dart.library.js_interop) 'web/notification_token_handle.dart';
+import 'handle_base.dart';
+
+abstract interface class NotificationTokenHandle extends HandleBase {}
diff --git a/packages/realm_dart/lib/src/handles/object_changes_handle.dart b/packages/realm_dart/lib/src/handles/object_changes_handle.dart
new file mode 100644
index 000000000..6a42fa2d7
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/object_changes_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'handle_base.dart';
+
+abstract interface class ObjectChangesHandle extends HandleBase {
+  bool get isDeleted;
+  List<int> get properties;
+}
diff --git a/packages/realm_dart/lib/src/handles/object_handle.dart b/packages/realm_dart/lib/src/handles/object_handle.dart
index 2fc8c6dd7..a3ceaa60a 100644
--- a/packages/realm_dart/lib/src/handles/object_handle.dart
+++ b/packages/realm_dart/lib/src/handles/object_handle.dart
@@ -1,5 +1,55 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/object_handle.dart'
-    if (dart.library.js_interop) 'web/object_handle.dart';
+import '../realm_class.dart';
+import 'handle_base.dart';
+import 'list_handle.dart';
+import 'map_handle.dart';
+import 'notification_token_handle.dart';
+import 'realm_handle.dart';
+import 'results_handle.dart';
+import 'set_handle.dart';
+
+abstract interface class ObjectHandle extends HandleBase {
+  ObjectHandle createEmbedded(int propertyKey);
+  (ObjectHandle, int) get parent;
+
+  int get classKey;
+
+  bool get isValid;
+
+  Link get asLink;
+
+  // TODO: avoid taking the [realm] parameter
+  Object? getValue(Realm realm, int propertyKey);
+
+  // TODO: value should be RealmValue, and perhaps this method should be combined
+  // with setCollection?
+  void setValue(int propertyKey, Object? value, bool isDefault);
+  ListHandle getList(int propertyKey);
+  SetHandle getSet(int propertyKey);
+  MapHandle getMap(int propertyKey);
+  ResultsHandle getBacklinks(int sourceTableKey, int propertyKey);
+
+  void setCollection(Realm realm, int propertyKey, RealmValue value);
+
+  String objectToString();
+  void delete();
+
+  ObjectHandle? resolveIn(RealmHandle frozenRealm);
+
+  NotificationTokenHandle subscribeForNotifications(NotificationsController controller, [List<String>? keyPaths]);
+
+  void verifyKeyPath(List<String>? keyPaths);
+
+  @override
+  // equals handled by HandleBase<T>
+  // ignore: hash_and_equals
+  int get hashCode => asLink.hash;
+}
+
+abstract class Link {
+  int get targetKey;
+  int get classKey;
+  int get hash;
+}
diff --git a/packages/realm_dart/lib/src/handles/realm_handle.dart b/packages/realm_dart/lib/src/handles/realm_handle.dart
index 9a2522cc0..a70d0817f 100644
--- a/packages/realm_dart/lib/src/handles/realm_handle.dart
+++ b/packages/realm_dart/lib/src/handles/realm_handle.dart
@@ -1,5 +1,69 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/realm_handle.dart'
-    if (dart.library.js_interop) 'web/realm_handle.dart';
+import '../realm_class.dart';
+import '../realm_object.dart';
+import 'handle_base.dart';
+import 'object_handle.dart';
+import 'results_handle.dart';
+import 'schema_handle.dart';
+import 'session_handle.dart';
+import 'subscription_set_handle.dart';
+
+import 'native/realm_handle.dart' if (dart.library.js_interop) 'web/realm_handle.dart' as impl;
+
+abstract interface class RealmHandle extends HandleBase {
+  factory RealmHandle.open(Configuration config) = impl.RealmHandle.open;
+
+  int addChild(HandleBase child);
+  void removeChild(int id);
+
+  @override
+  void releaseCore();
+
+  ObjectHandle createWithPrimaryKey(int classKey, Object? primaryKey);
+
+  ObjectHandle create(int classKey);
+  ObjectHandle getOrCreateWithPrimaryKey(int classKey, Object? primaryKey);
+
+  bool compact();
+
+  void writeCopy(Configuration config);
+  ResultsHandle queryClass(int classKey, String query, List<Object?> args);
+  RealmHandle freeze();
+  SessionHandle getSession();
+  bool get isFrozen;
+
+  SubscriptionSetHandle get subscriptions;
+
+  void disableAutoRefreshForTesting();
+  void close();
+
+  bool get isClosed;
+
+  void beginWrite();
+
+  void commitWrite();
+
+  Future<void> beginWriteAsync(CancellationToken? ct);
+  Future<void> commitWriteAsync(CancellationToken? ct);
+  bool get isWritable;
+  void rollbackWrite();
+  bool refresh();
+  Future<bool> refreshAsync();
+  ResultsHandle findAll(int classKey);
+  ObjectHandle? find(int classKey, Object? primaryKey);
+  ObjectHandle? findExisting(int classKey, ObjectHandle other);
+  void renameProperty(String objectType, String oldName, String newName, SchemaHandle schema);
+  bool deleteType(String objectType);
+  ObjectHandle getObject(int classKey, int objectKey);
+
+  CallbackTokenHandle subscribeForSchemaNotifications(Realm realm);
+
+  RealmSchema readSchema();
+  Map<String, RealmPropertyMetadata> getPropertiesMetadata(int classKey, String? primaryKeyName);
+
+  RealmObjectMetadata getObjectMetadata(SchemaObject schema);
+}
+
+abstract class CallbackTokenHandle extends HandleBase {}
diff --git a/packages/realm_dart/lib/src/handles/results_handle.dart b/packages/realm_dart/lib/src/handles/results_handle.dart
index d4e4d4c67..69e05cc42 100644
--- a/packages/realm_dart/lib/src/handles/results_handle.dart
+++ b/packages/realm_dart/lib/src/handles/results_handle.dart
@@ -1,5 +1,28 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/results_handle.dart'
-    if (dart.library.js_interop) 'web/results_handle.dart';
+import 'package:realm_dart/src/handles/handle_base.dart';
+import 'package:realm_dart/src/handles/notification_token_handle.dart';
+
+import '../realm_class.dart';
+import 'object_handle.dart';
+import 'realm_handle.dart';
+
+abstract interface class ResultsHandle extends HandleBase {
+  ResultsHandle queryResults(String query, List<Object> args);
+
+  int find(Object? value);
+
+  ObjectHandle getObjectAt(int index);
+
+  int get count;
+
+  bool isValid();
+
+  void deleteAll();
+  ResultsHandle snapshot();
+  ResultsHandle resolveIn(RealmHandle realmHandle);
+
+  Object? elementAt(Realm realm, int index);
+  NotificationTokenHandle subscribeForNotifications(NotificationsController controller);
+}
diff --git a/packages/realm_dart/lib/src/handles/scheduler_handle.dart b/packages/realm_dart/lib/src/handles/scheduler_handle.dart
index b0b88e593..3a3682a7c 100644
--- a/packages/realm_dart/lib/src/handles/scheduler_handle.dart
+++ b/packages/realm_dart/lib/src/handles/scheduler_handle.dart
@@ -1,5 +1,12 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/scheduler_handle.dart'
-    if (dart.library.js_interop) 'web/scheduler_handle.dart';
+import 'handle_base.dart';
+
+import 'native/scheduler_handle.dart' if (dart.library.js_interop) 'web/scheduler_handle.dart' as impl;
+
+abstract interface class SchedulerHandle extends HandleBase {
+  factory SchedulerHandle(int isolateId, int sendPort) = impl.SchedulerHandle;
+
+  void invoke(int workQueue);
+}
diff --git a/packages/realm_dart/lib/src/handles/schema_handle.dart b/packages/realm_dart/lib/src/handles/schema_handle.dart
index 73445a6e2..39d153028 100644
--- a/packages/realm_dart/lib/src/handles/schema_handle.dart
+++ b/packages/realm_dart/lib/src/handles/schema_handle.dart
@@ -1,5 +1,11 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/schema_handle.dart'
-    if (dart.library.js_interop) 'web/schema_handle.dart';
+import '../configuration.dart';
+import 'handle_base.dart';
+
+import 'native/schema_handle.dart' if (dart.library.js_interop) 'web/schema_handle.dart' as impl;
+
+abstract interface class SchemaHandle extends HandleBase {
+  factory SchemaHandle.from(Iterable<SchemaObject> schema) = impl.SchemaHandle.from;
+}
diff --git a/packages/realm_dart/lib/src/handles/session_handle.dart b/packages/realm_dart/lib/src/handles/session_handle.dart
index ff4b82552..f5c3aeb15 100644
--- a/packages/realm_dart/lib/src/handles/session_handle.dart
+++ b/packages/realm_dart/lib/src/handles/session_handle.dart
@@ -1,5 +1,35 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/session_handle.dart'
-    if (dart.library.js_interop) 'web/session_handle.dart';
+import 'package:cancellation_token/cancellation_token.dart';
+
+import '../session.dart';
+import 'handle_base.dart';
+import 'user_handle.dart';
+
+abstract interface class SessionHandle extends HandleBase {
+  String get path;
+  ConnectionState get connectionState;
+
+  UserHandle get user;
+
+  SessionState get state;
+
+  void pause();
+
+  void resume();
+
+  void raiseError(int errorCode, bool isFatal);
+
+  Future<void> waitForUpload([CancellationToken? cancellationToken]);
+  Future<void> waitForDownload([CancellationToken? cancellationToken]);
+  SyncSessionNotificationTokenHandle subscribeForConnectionStateNotifications(SessionConnectionStateController controller);
+
+  SyncSessionNotificationTokenHandle subscribeForProgressNotifications(
+    ProgressDirection direction,
+    ProgressMode mode,
+    SessionProgressNotificationsController controller,
+  );
+}
+
+abstract interface class SyncSessionNotificationTokenHandle extends HandleBase {}
\ No newline at end of file
diff --git a/packages/realm_dart/lib/src/handles/set_handle.dart b/packages/realm_dart/lib/src/handles/set_handle.dart
index 1e1eb1073..bbad63523 100644
--- a/packages/realm_dart/lib/src/handles/set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/set_handle.dart
@@ -1,5 +1,34 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/set_handle.dart'
-    if (dart.library.js_interop) 'web/set_handle.dart';
+import 'package:realm_dart/src/handles/handle_base.dart';
+
+import '../realm_class.dart';
+import 'notification_token_handle.dart';
+import 'realm_handle.dart';
+import 'results_handle.dart';
+
+abstract interface class SetHandle extends HandleBase {
+  ResultsHandle get asResults;
+
+  ResultsHandle query(String query, List<Object?> args);
+
+  bool insert(Object? value);
+
+  // TODO: avoid taking the [realm] parameter
+  Object? elementAt(Realm realm, int index);
+  bool find(Object? value);
+
+  bool remove(Object? value);
+
+  void clear();
+  int get size;
+
+  bool get isValid;
+
+  void deleteAll();
+
+  SetHandle? resolveIn(RealmHandle frozenRealm);
+
+  NotificationTokenHandle subscribeForNotifications(NotificationsController controller);
+}
diff --git a/packages/realm_dart/lib/src/handles/subscription_handle.dart b/packages/realm_dart/lib/src/handles/subscription_handle.dart
index 10f79f5d7..7f3cc40e9 100644
--- a/packages/realm_dart/lib/src/handles/subscription_handle.dart
+++ b/packages/realm_dart/lib/src/handles/subscription_handle.dart
@@ -1,5 +1,16 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/subscription_handle.dart'
-    if (dart.library.js_interop) 'web/subscription_handle.dart';
+import 'package:realm_common/realm_common.dart';
+
+import 'handle_base.dart';
+
+abstract interface class SubscriptionHandle extends HandleBase {
+  ObjectId get id;
+  String? get name;
+  String get objectClassName;
+  String get queryString;
+  DateTime get createdAt;
+  DateTime get updatedAt;
+  bool equalTo(SubscriptionHandle other);
+}
diff --git a/packages/realm_dart/lib/src/handles/subscription_set_handle.dart b/packages/realm_dart/lib/src/handles/subscription_set_handle.dart
index 452510a76..82a2e1abe 100644
--- a/packages/realm_dart/lib/src/handles/subscription_set_handle.dart
+++ b/packages/realm_dart/lib/src/handles/subscription_set_handle.dart
@@ -1,5 +1,31 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/subscription_set_handle.dart'
-    if (dart.library.js_interop) 'web/subscription_set_handle.dart';
+import 'package:cancellation_token/cancellation_token.dart';
+
+import '../subscription.dart';
+import 'handle_base.dart';
+import 'mutable_subscription_set_handle.dart';
+import 'results_handle.dart';
+import 'subscription_handle.dart';
+
+abstract class SubscriptionSetHandle extends HandleBase {
+  void refresh();
+
+  int get size;
+
+  Exception? get error;
+
+  SubscriptionHandle operator [](int index);
+
+  SubscriptionHandle? findByName(String name);
+
+  SubscriptionHandle? findByResults(ResultsHandle results);
+
+  int get version;
+  SubscriptionSetState get state;
+
+  MutableSubscriptionSetHandle toMutable();
+
+  Future<SubscriptionSetState> waitForStateChange(SubscriptionSetState notifyWhen, [CancellationToken? cancellationToken]);
+}
diff --git a/packages/realm_dart/lib/src/handles/user_handle.dart b/packages/realm_dart/lib/src/handles/user_handle.dart
index 1060b55ea..cf498b10f 100644
--- a/packages/realm_dart/lib/src/handles/user_handle.dart
+++ b/packages/realm_dart/lib/src/handles/user_handle.dart
@@ -1,5 +1,33 @@
 // Copyright 2024 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-export 'native/user_handle.dart'
-    if (dart.library.js_interop) 'web/user_handle.dart';
+import 'package:realm_common/realm_common.dart';
+
+import '../user.dart';
+import 'app_handle.dart';
+import 'credentials_handle.dart';
+import 'handle_base.dart';
+
+abstract interface class UserHandle extends HandleBase {
+  AppHandle get app;
+  UserState get state;
+  String get id;
+  List<UserIdentity> get identities;
+  Future<void> logOut();
+  String? get deviceId;
+  UserProfile get profileData;
+  String get refreshToken;
+  String get accessToken;
+  String get path;
+  String? get customData;
+  Future<UserHandle> linkCredentials(AppHandle app, CredentialsHandle credentials);
+  Future<ApiKey> createApiKey(AppHandle app, String name);
+  Future<ApiKey> fetchApiKey(AppHandle app, ObjectId id);
+  Future<List<ApiKey>> fetchAllApiKeys(AppHandle app);
+  Future<void> deleteApiKey(AppHandle app, ObjectId id);
+  Future<void> disableApiKey(AppHandle app, ObjectId objectId);
+  Future<void> enableApiKey(AppHandle app, ObjectId objectId);
+  UserNotificationTokenHandle subscribeForNotifications(UserNotificationsController controller);
+}
+
+abstract interface class UserNotificationTokenHandle extends HandleBase {}
diff --git a/packages/realm_dart/lib/src/handles/web/app_handle.dart b/packages/realm_dart/lib/src/handles/web/app_handle.dart
new file mode 100644
index 000000000..45556bdeb
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/app_handle.dart
@@ -0,0 +1,13 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../../../realm.dart';
+import '../app_handle.dart' as intf;
+
+class AppHandle implements intf.AppHandle {
+  factory AppHandle.from(AppConfiguration configuration) => throw UnsupportedError('web not supported');
+  static AppHandle? get(String id, String? baseUrl) => throw UnsupportedError('web not supported');
+
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/async_open_task_handle.dart b/packages/realm_dart/lib/src/handles/web/async_open_task_handle.dart
new file mode 100644
index 000000000..12225d979
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/async_open_task_handle.dart
@@ -0,0 +1,14 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../async_open_task_handle.dart' as intf;
+
+class AsyncOpenTaskHandle implements intf.AsyncOpenTaskHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
+
+abstract class AsyncOpenTaskProgressNotificationTokenHandle implements intf.AsyncOpenTaskProgressNotificationTokenHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/collection_changes_handle.dart b/packages/realm_dart/lib/src/handles/web/collection_changes_handle.dart
new file mode 100644
index 000000000..7bc265a76
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/collection_changes_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../collection_changes_handle.dart' as intf;
+
+class CollectionChangesHandle implements intf.CollectionChangesHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/handle_base.dart b/packages/realm_dart/lib/src/handles/web/handle_base.dart
new file mode 100644
index 000000000..9d2c26ff0
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/handle_base.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../handle_base.dart' as intf;
+
+class HandleBase implements intf.HandleBase {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/list_handle.dart b/packages/realm_dart/lib/src/handles/web/list_handle.dart
new file mode 100644
index 000000000..9f8180a35
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/list_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../list_handle.dart' as intf;
+
+class ListHandle implements intf.ListHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/map_changes_handle.dart b/packages/realm_dart/lib/src/handles/web/map_changes_handle.dart
new file mode 100644
index 000000000..9e7d0f6ed
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/map_changes_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../map_changes_handle.dart' as intf;
+
+abstract class MapChangesHandle implements intf.MapChangesHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
\ No newline at end of file
diff --git a/packages/realm_dart/lib/src/handles/web/map_handle.dart b/packages/realm_dart/lib/src/handles/web/map_handle.dart
new file mode 100644
index 000000000..28970217a
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/map_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../map_handle.dart' as intf;
+
+class MapHandle implements intf.MapHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/object_changes_handle.dart b/packages/realm_dart/lib/src/handles/web/object_changes_handle.dart
new file mode 100644
index 000000000..300cb34a4
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/object_changes_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../object_changes_handle.dart' as intf;
+
+class ObjectChangesHandle implements intf.ObjectChangesHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/object_handle.dart b/packages/realm_dart/lib/src/handles/web/object_handle.dart
new file mode 100644
index 000000000..ba1be46fd
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/object_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../object_handle.dart' as intf;
+
+class ObjectHandle implements intf.ObjectHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/realm_handle.dart b/packages/realm_dart/lib/src/handles/web/realm_handle.dart
new file mode 100644
index 000000000..9521293dd
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/realm_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../realm_handle.dart' as intf;
+
+class RealmHandle implements intf.RealmHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/results_handle.dart b/packages/realm_dart/lib/src/handles/web/results_handle.dart
new file mode 100644
index 000000000..142779085
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/results_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../results_handle.dart' as intf;
+
+class ResultsHandle implements intf.ResultsHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/set_handle.dart b/packages/realm_dart/lib/src/handles/web/set_handle.dart
new file mode 100644
index 000000000..7eb07ad3f
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/set_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../set_handle.dart' as intf;
+
+class SetHandle implements intf.SetHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/subscription_handle.dart b/packages/realm_dart/lib/src/handles/web/subscription_handle.dart
new file mode 100644
index 000000000..dab3f79c5
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/subscription_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../subscription_handle.dart' as intf;
+
+class SubscriptionHandle implements intf.SubscriptionHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/subscription_set_handle.dart b/packages/realm_dart/lib/src/handles/web/subscription_set_handle.dart
new file mode 100644
index 000000000..69d710bd4
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/subscription_set_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../subscription_set_handle.dart' as intf;
+
+class SubscriptionSetHandle implements intf.SubscriptionSetHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/handles/web/user_handle.dart b/packages/realm_dart/lib/src/handles/web/user_handle.dart
new file mode 100644
index 000000000..baeef586a
--- /dev/null
+++ b/packages/realm_dart/lib/src/handles/web/user_handle.dart
@@ -0,0 +1,9 @@
+// Copyright 2024 MongoDB, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+import '../user_handle.dart' as intf;
+
+class UserHandle implements intf.UserHandle {
+  @override
+  noSuchMethod(Invocation invocation) => throw UnsupportedError('web not supported');
+}
diff --git a/packages/realm_dart/lib/src/realm_class.dart b/packages/realm_dart/lib/src/realm_class.dart
index d4c435113..ce4bcfebc 100644
--- a/packages/realm_dart/lib/src/realm_class.dart
+++ b/packages/realm_dart/lib/src/realm_class.dart
@@ -365,7 +365,6 @@ class Realm {
   T write<T>(T Function() writeCallback) {
     assert(!_isFuture<T>(), 'writeCallback must be synchronous');
     final transaction = beginWrite();
-
     try {
       T result = writeCallback();
       transaction.commit();
diff --git a/packages/realm_dart/lib/src/realm_object.dart b/packages/realm_dart/lib/src/realm_object.dart
index 4f2165602..f9c77720b 100644
--- a/packages/realm_dart/lib/src/realm_object.dart
+++ b/packages/realm_dart/lib/src/realm_object.dart
@@ -9,6 +9,7 @@ import 'package:realm_common/realm_common.dart';
 import 'configuration.dart';
 import 'handles/handle_base.dart';
 import 'handles/notification_token_handle.dart';
+import 'handles/object_changes_handle.dart';
 import 'handles/object_handle.dart';
 import 'handles/realm_library.dart';
 import 'list.dart';
@@ -175,6 +176,7 @@ class RealmCoreAccessor implements RealmAccessor {
           if (listMetadata != null && _isTypeGenericObject<T>()) {
             switch (listMetadata.schema.baseType) {
               case ObjectType.realmObject:
+                //ManagedRealmList<RealmObject>._(handle, object.realm, listMetadata);
                 return object.realm.createList<RealmObject>(handle, listMetadata);
               case ObjectType.embeddedObject:
                 return object.realm.createList<EmbeddedObject>(handle, listMetadata);
@@ -758,7 +760,7 @@ class RealmObjectNotificationsController<T extends RealmObjectBase> extends Noti
         throw RealmException("It is not allowed to have empty key paths.");
       }
       // throw early if the key paths are invalid
-      realmObject.handle.buildAndVerifyKeyPath(keyPaths);
+      realmObject.handle.verifyKeyPath(keyPaths);
     }
   }
 
diff --git a/packages/realm_dart/lib/src/subscription.dart b/packages/realm_dart/lib/src/subscription.dart
index 12bf8c6c1..2fc945854 100644
--- a/packages/realm_dart/lib/src/subscription.dart
+++ b/packages/realm_dart/lib/src/subscription.dart
@@ -111,11 +111,9 @@ enum SubscriptionSetState {
 /// {@category Sync}
 sealed class SubscriptionSet with Iterable<Subscription> {
   final Realm _realm;
-  SubscriptionSetHandle __handle;
-  SubscriptionSetHandle get _handle => __handle.nullPtrAsNull ?? (throw RealmClosedError('Cannot access a SubscriptionSet that belongs to a closed Realm'));
-  set _handle(SubscriptionSetHandle value) => __handle = value;
+  SubscriptionSetHandle _handle;
 
-  SubscriptionSet._(this._realm, this.__handle);
+  SubscriptionSet._(this._realm, this._handle);
 
   /// Finds an existing [Subscription] in this set by its query
   ///
diff --git a/packages/realm_dart/test/subscription_test.dart b/packages/realm_dart/test/subscription_test.dart
index ab9fa7f2e..819fbee6d 100644
--- a/packages/realm_dart/test/subscription_test.dart
+++ b/packages/realm_dart/test/subscription_test.dart
@@ -6,11 +6,10 @@ import 'dart:io';
 import 'dart:math';
 import 'dart:typed_data';
 
-import 'package:test/expect.dart' hide throws;
-
 import 'package:realm_dart/realm.dart';
 import 'package:realm_dart/src/handles/realm_core.dart';
 import 'package:realm_dart/src/subscription.dart';
+
 import 'test.dart';
 
 void main() {
@@ -549,7 +548,7 @@ void main() {
     expect(() => subscriptions.state, returnsNormally);
 
     realm.close();
-    expect(() => subscriptions.state, throws<RealmClosedError>());
+    expect(() => subscriptions.state, throws<RealmError>());
   });
 
   baasTest('SyncSessionErrorCode.compensatingWrite', (configuration) async {