backend-python

FastAPI with SQLAlchemy 2.0 and Pydantic v2 provides a modern Python backend stack for building type-safe APIs. This approach combines async request handling, ORM-based database interactions, and automatic request validation into a cohesive framework suitable for production APIs and async services.

FastAPI's built-in dependency injection system wires services, database sessions, and configuration into route handlers declaratively. The Skill covers patterns for organizing dependencies, managing async SQLAlchemy sessions, and structuring reusable components across your codebase.

Async SQLAlchemy integrates with FastAPI's async runtime to perform non-blocking database operations. This Skill demonstrates async session management, proper connection pooling, and query patterns that leverage both frameworks' asynchronous capabilities without blocking the event loop.

Pydantic v2 validates incoming API requests and serializes ORM model instances to JSON. This Skill shows how to define validation schemas, map Pydantic models to SQLAlchemy entities, and handle serialization with type safety across your FastAPI endpoints.

Testing a modern Python backend requires fixtures for database setup, test clients for API routes, and factories for generating valid test data. This Skill covers integrated linting, formatting, and testing tooling alongside patterns for isolating units and mocking dependencies.

Settings management separates environment variables from application logic using Pydantic for validation. This Skill demonstrates how to load, validate, and inject configuration across FastAPI services, supporting development, testing, and production deployment scenarios.