The Python AI App Stack I’d Actually Ship in 2026 (not just demo)

A walkthrough of the tech stack for building a production-ready full-stack AI app using Python. The stack covers FastAPI for the backend, React+Vite for the frontend in a monorepo, Supabase for PostgreSQL database and file storage, Celery with Redis for background job queuing, SQLAlchemy/SQLModel as ORM, and Pydantic AI as an AI SDK abstraction. The demo app is an AI YouTube thumbnail generator that uses hybrid semantic+keyword search via pgvector embeddings. Key architectural decisions include decoupled frontend/backend, async job queuing to avoid blocking users during AI inference, and polling for job status updates.