FastAPI + SQLAlchemy + PostgreSQL overview

Python API stack: FastAPI as the ASGI web framework, SQLAlchemy as the ORM with its declarative mapping and async engine (via asyncpg), and PostgreSQL as the primary data store. Pydantic models serve double duty as both request/response schemas and validation layer. Alembic handles database migrations. The stack is popular for data-intensive REST and async APIs where Python's ecosystem (pandas, scikit-learn, Celery) needs to plug in alongside a web layer. Uvicorn or Gunicorn+Uvicorn workers serve the ASGI app. Deployment targets include Docker on Railway, Fly.io, or GCP Cloud Run. pytest with httpx and pytest-asyncio is the idiomatic testing setup.