I am a freelancer, I need to develop a full stack app for a client. The frontend will be an SPA. The backend will be an API that makes calls to generative AI so I would like to use LangChain (or LangChain4J). I have more experience with Java/Spring Boot, but Python seems the best fit since its using AI and allows for simpler/more rapid development. I will be the lead developer on this project, aided only by a junior dev. My question is : how robust and production-ready is FastAPI ? I'm not interested in performance, I want the software to work well, be robust in production and scalable.