fastapi-patterns

Structure a FastAPI application for production using an application factory pattern to create app instances, separating routers, services, and schemas into a modular, scalable project layout.

Dependency injection for multi-tenant APIs in FastAPI works by resolving tenant context within middleware and passing tenant-specific configurations or database sessions down to individual routers.

Organize routers and middleware in FastAPI by applying an application factory approach that registers CORS, logging, and tenant resolution middleware globally, while grouping API routes into modular router files.

Yes, using an application factory pattern for FastAPI testing and production allows you to create consistent app instances with controlled lifecycles, enabling robust integration tests and scalable deployments.

Implement API-first design and testing in FastAPI by driving development with OpenAPI specifications, enforcing integration tests against generated endpoints, and maintaining clear documentation.

FastAPI supports tenant isolation across multiple routers by combining middleware for tenant resolution with dependency injection to enforce data boundaries within each service layer.