[filmor]

cffi replaces ctypes, which is a completely different thing. cpyext is a reimplementation of the Python C-API, so no attempt at improving the API.

HPy on CPython uses the existing C-API under the hood, so there is zero need to build up some keep someone out...

[kagerl]

cffi is used to wrap c libraries. Only a masochist would use ctypes to wrap a whole library. While both are technically FFIs, it does not make sense to compare them. From a conceptual perspective, cffi was written to replace the C-API for C modules.