In the standard cython build process, running myprogram.py(x) with cython requires creating myprogram.c, setup.py, myprogram.so, and finally_use.py. The popular pyximport tool reduces these 5 files down to 2, but is only designed to handle simple builds, and must eventually be replaced with a setup.py build for any real project. Runcython goes the last mile, and requires only one file. It's also designed to support complex builds in a way that will be intimately familiar for any c/c++ hacker. You can use runcython file.pyx just like you would use python file.py. The difference is that runcython will run a file with arbitrary cython code.