fastapi-clean-architecture

FastAPI clean architecture structures applications into distinct repository, service, and API layers. It uses dependency injection via the Depends function to pass database sessions and ensure dependency inversion, preventing layer leaks and keeping business logic separate from routing.

The repository pattern in FastAPI abstracts database operations into a separate layer, isolating SQLAlchemy queries from your service layer. You need it to maintain clean architecture boundaries, making your data access logic testable and swappable without modifying core business rules.

JWT login and authentication in FastAPI clean architecture involve routing requests through an APIRouter to a service layer that validates credentials and generates tokens. Dependency injection secures endpoints by validating JWTs before the service executes authorized CRUD operations.

Yes, SQLAlchemy and Alembic integrate directly into FastAPI clean architecture. SQLAlchemy manages repository-level ORM interactions, while Alembic handles schema migrations, ensuring your database structure evolves alongside your Pydantic schemas and service layer logic without architectural conflicts.

FastAPI clean architecture relies on Pydantic schemas to validate data boundaries between the API and service layers. Defining explicit schemas for every CRUD operation ensures strict type checking and prevents unvalidated data from reaching your repository or core business logic.

FastAPI service layer dependency leaks occur when higher-level modules depend directly on lower-level concrete implementations. Fix this by applying dependency inversion using FastAPI's Depends function to inject interfaces, ensuring your service layer remains decoupled from SQLAlchemy repositories.