Flutter Interview Questions Part 4: Networking, Storage & Testing

Welcome to Part 4 of the Flutter Interview Questions series! This installment dives deep into three pillars that every production Flutter app relies on: networking , local storage , and testing . Whether you are preparing for your next Flutter interview or looking to solidify your understanding of how data flows in and out of a Flutter application and how to verify it all works, this part has you covered. This is part 4 of a 14-part series, so be sure to bookmark it and follow along as we release new parts. What's in this part? Networking -- HTTP & Dio packages, interceptors, request cancellation, REST API integration, JSON parsing ( json_serializable , freezed ), GraphQL, WebSockets, error handling, SSL pinning Local Storage -- SharedPreferences, SQLite/sqflite/Drift, Hive, Isar, file storage with path_provider , secure storage with flutter_secure_storage Testing -- Unit testing, widget testing, integration testing, mocking (Mockito & Mocktail), golden tests, test coverage, BLoC testi