Gateway Builder

Design gateways using Protocol interfaces that define contracts for external service calls. Create a `gateways/interfaces.py` file with Protocol definitions, then implement concrete gateway classes that accept and return domain models while hiding external API types behind the interface abstraction.

Dependency injection enables clean architecture by decoupling business logic from infrastructure specifics. It makes gateways mockable for unit testing and allows you to swap implementations—such as switching between real AWS calls and test doubles—without changing application code.

Yes. Gateway patterns are specifically designed for third-party API integration within clean architecture. Define a Protocol interface, implement a concrete gateway that translates between domain models and external API contracts, then inject it into use cases to shield business logic from API details.

Implement error handling and retry logic within gateway classes so external service failures don't propagate directly to business logic. Configure retry policies and error mappings in the gateway constructor, allowing use cases to work with domain-level exceptions that abstract infrastructure concerns.

Define gateways as Protocol interfaces and inject mock implementations in tests. Since gateways accept and return domain models rather than external API types, you can easily create test doubles that simulate service behavior without calling real external systems.

Yes. Pass configuration such as API endpoints, credentials, and timeout settings to the gateway constructor or use constants. This allows the same gateway implementation to work across development, testing, and production environments through dependency injection.