Swagen - Swagger to Flutter Clean Architecture Generator

Swagen is a powerful code generator that converts Swagger/OpenAPI 3.0 specifications into a fully structured Flutter project following Clean Architecture principles.

With Swagen, you can automatically generate:

Models & Entities
Remote DataSources
Repositories & Repository Implementations
UseCases
Providers
GetIt Injector for dependency management

It supports Swagger v3 input from:

Local JSON files (swagger.json)
Local YAML files (swagger.yaml)
Remote URLs (https://example.com/swagger.json)

Swagen simplifies the process of turning an API specification into a ready-to-use Flutter application with clean and maintainable architecture.

Usage

Swagen can be installed locally in a Flutter project or globally on your system. The usage differs slightly depending on the installation method.

Local Installation (Project-Specific)

Install Swagen in your Flutter project:

flutter pub add swagen

Run the generator using dart run:

Convert a local Swagger file

dart run swagen convert path/to/swagger.json

Convert from a URL

dart run swagen convert https://example.com/swagger.json

Features

1. Auto-generated Clean Architecture Layers

For each feature in your API, Swagen generates:

Data Layer
- Models for API responses
- RemoteDataSource using http client and FlutterSecureStorage for token handling
- RepositoryImpl implementing the feature repository interface
Domain Layer
- Entities representing your core business objects
- Repository interface
- UseCases encapsulating business logic
Presentation Layer
- Providers for state management (using ChangeNotifier)

2. Dependency Injection

Generates a ready-to-use injector.dart with GetIt.
All Providers, UseCases, Repositories, and DataSources are registered automatically.
Supports lazy singletons for UseCases and Repositories and factories for Providers.

3. Security Support

Handles Bearer Token authentication automatically.
Uses FlutterSecureStorage to store JWT tokens securely.
DataSource automatically attaches tokens to requests if configured.

4. HTTP Requests

Uses http package for all API calls.
Supports GET, POST, PUT, PATCH, DELETE methods.
Automatically converts JSON responses into strongly typed Models and Entities.

5. Swagger / OpenAPI Support

Accepts local .json file or URL.
Supports:
- Parameters (query, path, header)
- Inline schemas
- Nested entities
Auto-generates method names and UseCases based on operationId or endpoint path.

Command

Swagen can generate a Flutter Clean Architecture project from a Swagger/OpenAPI file, either from a local JSON file or a remote URL. Below are the commands and explanations:

1. Generate from a local Swagger file

dart run swagen convert path/swagger.json

dart run swagen convert → Runs the Swagen converter.
path/swagger.json → Path to your local Swagger/OpenAPI JSON file.
Generates models, entities, repositories, usecases, providers, and injector automatically.

2. Generate from a remote Swagger URL

dart run swagen convert https://example.com/swagger.json

https://example.com/swagger.json → URL of the Swagger/OpenAPI JSON file.
Useful if your API specification is hosted online.
Everything else is generated the same as the local file command.

3. Specify a custom package name

dart run swagen convert swagger.json --package music_app

--package music_app → Sets the package name used in import statements and generated code.
Example: Instead of default package name from pubspec.yaml, it will use music_app in imports.

4. Generate Clean Architecture interactively

dart run swagen cleanarch

Prompts you to enter the number of features in your API
Asks for feature names one by one (e.g., auth, user, artist).
Generates:
- Data Layer: models, - datasources, repositories
- Domain Layer: entities, repositories, usecases
- Presentation Layer: providers

5. Help command

dart run swagen help

Displays all available commands with explanations.

6. Version command

dart run swagen version

Displays the current version of Swagen.
Shows the GitHub repository link for updates and issues.

Project Structure

After running Swagen, your Flutter project will have a clean architecture structure like this:

📦lib
 ┣ 📂core
 ┃ ┣ 📂error
 ┃ ┃ ┣ 📜exception.dart
 ┃ ┃ ┗ 📜failure.dart
 ┃ ┣ 📂injector
 ┃ ┃ ┗ 📜injector.dart
 ┃ ┗ 📂state
 ┃ ┃ ┗ 📜request_state.dart
 ┣ 📂features
 ┃ ┣ 📂auth
 ┃ ┃ ┣ 📂data
 ┃ ┃ ┃ ┣ 📂datasources
 ┃ ┃ ┃ ┃ ┗ 📜auth_remote_data_source.dart
 ┃ ┃ ┃ ┣ 📂models
 ┃ ┃ ┃ ┃ ┣ 📜auth_response.dart
 ┃ ┃ ┃ ┃ ┗ 📜user_response.dart
 ┃ ┃ ┃ ┗ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜auth_repository.dart
 ┃ ┃ ┣ 📂domain
 ┃ ┃ ┃ ┣ 📂entities
 ┃ ┃ ┃ ┃ ┣ 📜auth.dart
 ┃ ┃ ┃ ┃ ┗ 📜user.dart
 ┃ ┃ ┃ ┣ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜auth_repository.dart
 ┃ ┃ ┃ ┗ 📂usecases
 ┃ ┃ ┃ ┃ ┣ 📜login.dart
 ┃ ┃ ┃ ┃ ┗ 📜register.dart
 ┃ ┃ ┣ 📂presentation
 ┃ ┃ ┃ ┗ 📂providers
 ┃ ┃ ┃ ┃ ┣ 📜login_provider.dart
 ┃ ┃ ┃ ┃ ┗ 📜register_provider.dart
 ┃ ┃ ┗ 📜injector.dart
 ┃ ┣ 📂products
 ┃ ┃ ┣ 📂data
 ┃ ┃ ┃ ┣ 📂datasources
 ┃ ┃ ┃ ┃ ┗ 📜products_remote_data_source.dart
 ┃ ┃ ┃ ┣ 📂models
 ┃ ┃ ┃ ┃ ┗ 📜product_response.dart
 ┃ ┃ ┃ ┗ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜products_repository.dart
 ┃ ┃ ┣ 📂domain
 ┃ ┃ ┃ ┣ 📂entities
 ┃ ┃ ┃ ┃ ┗ 📜product.dart
 ┃ ┃ ┃ ┣ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜products_repository.dart
 ┃ ┃ ┃ ┗ 📂usecases
 ┃ ┃ ┃ ┃ ┣ 📜add_product.dart
 ┃ ┃ ┃ ┃ ┗ 📜get_product_by_id.dart
 ┃ ┃ ┣ 📂presentation
 ┃ ┃ ┃ ┗ 📂providers
 ┃ ┃ ┃ ┃ ┣ 📜add_product_provider.dart
 ┃ ┃ ┃ ┃ ┗ 📜get_product_by_id_provider.dart
 ┃ ┃ ┗ 📜injector.dart
 ┃ ┗ 📂users
 ┃ ┃ ┣ 📂data
 ┃ ┃ ┃ ┣ 📂datasources
 ┃ ┃ ┃ ┃ ┗ 📜users_remote_data_source.dart
 ┃ ┃ ┃ ┣ 📂models
 ┃ ┃ ┃ ┃ ┣ 📜user_list_response.dart
 ┃ ┃ ┃ ┃ ┗ 📜user_response.dart
 ┃ ┃ ┃ ┗ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜users_repository.dart
 ┃ ┃ ┣ 📂domain
 ┃ ┃ ┃ ┣ 📂entities
 ┃ ┃ ┃ ┃ ┗ 📜user.dart
 ┃ ┃ ┃ ┣ 📂repositories
 ┃ ┃ ┃ ┃ ┗ 📜users_repository.dart
 ┃ ┃ ┃ ┗ 📂usecases
 ┃ ┃ ┃ ┃ ┣ 📜create_user.dart
 ┃ ┃ ┃ ┃ ┗ 📜get_users.dart
 ┃ ┃ ┣ 📂presentation
 ┃ ┃ ┃ ┗ 📂providers
 ┃ ┃ ┃ ┃ ┣ 📜create_user_provider.dart
 ┃ ┃ ┃ ┃ ┗ 📜get_users_provider.dart
 ┣ ┗ ┗ 📜injector.dart