diff --git a/lib/services/sync/sync_providers.dart b/lib/services/sync/sync_providers.dart
index a290713..f714c7c 100644
--- a/lib/services/sync/sync_providers.dart
+++ b/lib/services/sync/sync_providers.dart
@@ -16,7 +16,16 @@ import 'sync_outbox.dart';
 
 final r2UploadServiceProvider = Provider<R2UploadService>((ref) => R2UploadService());
 final syncBundleWorkerProvider = Provider<SyncBundleWorker>((ref) => SyncBundleWorker(ref.watch(databaseProvider)));
-final syncOutboxProvider = Provider<SyncOutbox>((ref) => SyncOutbox(ref.watch(sharedPreferencesProvider)));
+
+/// Cloud sync state is account-scoped. The Firebase UID is intentionally part
+/// of the persisted namespace so signing out and into another account cannot
+/// inherit the previous account's synced/pending/failed ride state.
+final syncOutboxProvider = Provider<SyncOutbox>((ref) {
+  final prefs = ref.watch(sharedPreferencesProvider);
+  final user = ref.watch(currentUserProvider);
+  final namespace = user?.uid ?? 'local';
+  return SyncOutbox(prefs, storageNamespace: namespace);
+});
 
 final firebaseSyncProvider = Provider<FirebaseSyncProvider>((ref) => FirebaseSyncProvider(
       db: ref.watch(databaseProvider),