We've been slowly developing an API for PythonAnywhere, and we've now enabled it so that all users can try it out if they wish. Head over to your accounts page and find the "API Token" tab to get started.
The API is still very much in beta, and it's by no means complete! We've started out with a few endpoints that we thought we ourselves would find useful, and some that we needed internally.
Probably the most interesting functionality that it exposes at the moment is the ability to create, modify, and reload a webapp remotely, but there's a few other things in there as well, like file and console sharing. You can find a full list of endpoints here: http://help.pythonanywhere.com/pages/API
We're keen to hear your thoughts and suggestions!