Cyclone is a web server framework for Python that implements the Tornado API as a Twisted protocol.

Twisted is an event-driven network programming framework for Python, that dates back from 2002. It’s one of the most mature libraries for non-blocking I/O available to the public. Tornado is the open source version of FriendFeed’s web server, one of the most popular and fast web servers for Python, with a very decent API for building web applications.

The idea is to bridge Tornado's elegant and straightforward API to Twisted's Event-Loop, enabling a vast number of supported protocols.

This combination provides the ground for building up hybrid servers capable of handling HTTP very efficiently while also serve or use e-mail, ssh, sip, irc, etc, all concurrently.

On top of this rich feature set, Cyclone also addresses the C10K problem. For more information check

Quick links

Download from PyPI
Source code (github)
Mailing list


Cyclone is listed in PyPI and can be installed with pip or easy_install. Note that the source distribution includes demo applications that are not present when Cyclone is installed via packages, so you may want to download a copy of the source tarball as well.

Download the latest version from

tar zxvf cyclone-$VERSION.tar.gz
cd cyclone-$VERSION
sudo python install

The Cyclone source code is hosted on GitHub:


Cyclone runs on Python 2.5, 2.6 and 2.7, and requires:

Heads up! On Python 2.5, simplejson is required too.


Get up to speed with our comprehensive demo applications:

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