Cython is written in Python and C and works on Windows, macOS, and Linux, producing C source files compatible with CPython 2.6, 2.7, and 3.3 and later versions.

Choosing this arrangement saved considerably on Cython's development time, but modules have a dependency on the Python interpreter and standard library.

[9] Cython has a foreign function interface for invoking C/C++ routines and the ability to declare the static type of subroutine parameters and results, local variables, and class attributes.

For example: A sample hello world program for Cython is more complex than in most languages because it interfaces with the Python C API and setuptools or other PEP517-compliant extension building facilities.

[jargon] At least three files are required for a basic project: The following code listings demonstrate the build and launch process: These commands build and launch the program: A more straightforward way to start with Cython is through command-line IPython (or through in-browser python console called Jupyter notebook): which gives a 95 times improvement over the pure-python version.

[28] Cython can also be used to develop parallel programs for multi-core processor machines; this feature makes use of the OpenMP library.