PyPy exposes a subset of the CPython C API, which is good enough for many C extensions, and some others can be ported with little effort. Most other Python imp

PyPy exposes a subset of the CPython C API, which is good enough for many C extensions, and some others can be ported with little effort. Most other Python implementations don't provide any way to use CPython C extensions. There is also the HPy API and ABI, which some C extensions target and multiple Python implementations can compile or load.