CPython

CPython is the default, most-widely used implementation of the Python programming language. It is written in C. In addition to CPython, there are other "production-quality" Python implementations: Jython, written in Java, PyPy, and IronPython, which is written for the Common Language Infrastructure. There are also several experimental implementations.

CPython is a bytecode interpreter. It has a foreign function interface with several languages including C, in which one must explicitly write bindings in a language other than Python.