fastapi

Building FastAPI applications involves defining Pydantic models for validation and using asynchronous routing for concurrent request handling. You structure the application using modular routers and dependency injection to achieve scalable async APIs.

FastAPI dependency injection handles authentication by passing callable dependencies into route operations. This mechanism validates user credentials and manages access control across your API endpoints before executing the main route logic.

Yes, FastAPI supports middleware for processing requests globally and provides patterns for async database integration. This allows you to manage database sessions asynchronously and intercept HTTP requests across your modern API architecture.

The best way to organize FastAPI application structure is by using APIRouters to split endpoints into modular files. This pattern separates route logic, Pydantic models, and dependencies, ensuring maintainable and scalable async API design.

Yes, FastAPI automatically generates OpenAPI documentation based on your Pydantic models and route decorators. It inspects your endpoint signatures and data types to produce interactive API docs without requiring manual specification.

FastAPI handles validation errors automatically by returning standardized HTTP 422 responses when incoming data violates Pydantic models. You can implement custom error handling by registering exception handlers to manage application-specific errors across your routers.