ws4py requires Python 2.7+ or Python 3+. It also works with PyPy 1.8+. Note that ws4py will not try to automatically install dependencies and will let you decide which one you need.
ws4py comes with three client implementation depending of your own needs.
Built-in
That client is solely based on the Python stdlib, it uses a thread to run the inner processing loop.
Tornado
The Tornado client requires Tornado 2.0+
gevent
The gevent client requires gevent 0.13.6 or 1.0.0-dev
ws4py comes with two server implementation depending of your own needs.
CherryPy
The CherryPy server requires CherryPy 3.2.2+
gevent
The gevent server requires gevent 0.13.6 or 1.0.0-dev