This is a python wrapper around libuv not a pure python solution (not that it’s bad but it explains the click bait title).

Would a framework like uvicorn/fastapi be able to achieve similar performance if it were backed by libuv (as opposed to e.g. asyncio)?

Pydantic is unreasonably slow for big datastructures, though. For simple performance tests with simple requests/response it's probably fast. But with lots of the data marshalling happening in python some things are really slow in real life use cases.

[0] -- https://github.com/pydantic/pydantic-core