Waitress is meant to be a production-quality pure-Python WSGI server with very
acceptable performance.  It has no dependencies except ones which live in the
Python standard library.  It runs on CPython on Unix and Windows under Python
2.6+ and Python 3.2+.  It is also known to run on PyPy 1.6.0+ on UNIX.  It
supports HTTP/1.0 and HTTP/1.1.