Wikipedia
PythonAnywhere is an online Integrated Development Environment (IDE) and Web hosting service based on the Python programming language. It provides in-browser access to server-based Python and Bash Command-line interfaces, along with a code editor with Syntax highlighting. Program files can be transferred to and from the service using the user's browser. Web applications hosted by the service can be written using any WSGI-based application framework.
PythonAnywhere was created by Resolver Systems, who also produced Resolver One, a Python-based Spreadsheet program. On 16 October 2012 the product was acquired by a new company, PythonAnywhere LLP, who will develop and maintain the product in the future, and have taken on the existing development team.
The development team use PythonAnywhere to develop PythonAnywhere, and say that its collaboration features help because they use the Extreme Programming methodology.