I'm currently evaluating Python frameworks for a new project. I've built a number of applications with Flask / Django over the years, but also recently discovered FastAPI, which is built on Starlette. I tried it out for a small hobby app locally and enjoyed the experience so far. I liked how you could define types with Pydantic, the dependency injection, and how it seemed a little easier to bootstrap and form a project structure vs. flask. The auto API docs are great as well. Also the FastAPI documentation itself seemed very thorough and had great examples for authentication, docker images, boilerplates, etc. The project and docs feel mature.
That said, I don't see as much written about FastAPI and Starlette. I want to recommend it for a major project. Is there a large community around Starlette/FastAPI? Have you used it for large mission critical projects with many users? Would love to hear more about real world usage.