How do you choose local storage in Flutter?

Local persistence is not one problem. Preferences are small key-value pairs. Structured records need queries and migrations. Secrets need platform-backed encryption. Large binary data belongs in files or a database, not in preferences. Picking one tool for all four creates either insecure secrets or unmaintainable queries.

Future<void> saveThemeMode(String mode) async {
  final prefs = await SharedPreferences.getInstance();
  await prefs.setString('theme_mode', mode);
}

Future<String?> readThemeMode() async {
  final prefs = await SharedPreferences.getInstance();
  return prefs.getString('theme_mode');
}

• shared_preferences is for simple flags and settings, not for lists of records
• sqflite or Drift suits relational data, joins and migrations
• Hive or Isar can be fast for object stores, but evaluate maintenance and query needs
• flutter_secure_storage uses Keychain on iOS and Keystore-backed storage on Android
• path_provider gives a correct application documents or cache directory

Migration and consistency

Any schema will change. Version the database and write explicit migrations that run once, with tests from old fixtures. Decide what happens when a migration fails: preserve the old data, surface an error, or reset only cached non-critical data. Never silently delete user data.