- Python/C API Reference Manual
- HPy: a better API for Python
- Cython: C-extensions for Python
- Old 2to3c project by David Malcolm which uses Coccinelle to ease migration of C extensions from Python 2 to Python 3. See also 2to3c: an implementation of Python's 2to3 for C code article (2009).
- PEPs related to the C API:
- Make structures opaque