Here's how IDLE, Komodo, PyCharm, PyDev, Microsoft's Python and Python Tools ... Python projects benefit from ... but the chief drawback there is the absence of per-project configuration.

Pyrefly is not the first Python type-checking tool from Meta. Previously, the company delivered Pyre, written in OCaml. Pyre has since been retired; Pyrefly, written from scratch in Rust, replaces it.