Flutter Repository Pattern Explained (Stop Accessing APIs Directly)

Flutter Repository Pattern Explained (Stop Accessing APIs Directly) If your BLoC is calling APIs directly… 👉 your architecture is already broken. It might work today — but as your app grows, it turns into a nightmare: Hard to test ❌ Hard to scale ❌ Impossible to swap data sources ❌ Let’s fix that properly. 🧠 The Real Problem Most Flutter apps look like this: final response = await dio.get('/users'); Inside: BLoC ❌ UI ❌ Even widgets sometimes ❌ 👉 This creates tight coupling between your app and your API. 🏗️ The Solution: Repository Pattern The repository acts as a bridge between: Data sources (API, local DB) Domain layer (business logic, BLoC) UI → Bloc → UseCase → Repository → DataSource 👉 Your app depends on abstraction, not implementation. 📦 Step 1: Define Repository Contract (Domain Layer) abstract class UserRepository { Future<User> getUser(int id); } ✔ No API ✔ No JSON ✔ Pure business logic contract 🔌 Step 2: Create Data Source (Data Layer) class UserRemoteDataSource