API Request Handling — Web Development

FastAPI is a web framework for building APIs with Python. It leverages standard language type hints to provide automatic data validation, request parsing, and interactive API documentation generation. The framework supports asynchronous request handling and manages execution contexts to prevent blocking the main event loop. The project includes a dependency injection system that allows for the resolution and injection of reusable components into request handlers. This system supports request-scoped caching, lifecycle management, and integration with security mechanisms like OAuth2 and JSON Web Tokens. Developers can organize applications into modular routers and mount sub-applications to manage complex routing logic. Infrastructure features include middleware support for cross-origin resource sharing, background task management, and static file serving. The framework automatically generates OpenAPI specifications for defined endpoints, which can be customized through metadata and schema extensions. Testing utilities are provided to simulate HTTP and WebSocket connections, allowing for isolated verification of application behavior.