Tornado is an open source version of the scalable, non-blocking web server and and tools that power FriendFeed. Documentation and downloads are available at http://www.tornadoweb.org/
Tornado is licensed under the Apache Licence, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0.html).
Tornado 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 Tornado is installed in this way, so you may wish to download a copy of the source tarball as well.
tar xvzf tornado-2.3.tar.gz cd tornado-2.3 python setup.py build sudo python setup.py install
The Tornado source code is hosted on GitHub: https://github.com/facebook/tornado
On Python 2.6 and 2.7, it is also possible to simply add the tornado directory to your PYTHONPATH instead of building with setup.py, since the standard library includes epoll support.
Tornado runs on Python 2.5, 2.6, 2.7 and 3.2.
On Python 2.6 and 2.7, there are no dependencies outside the Python standard library, although PycURL (version 7.18.2 or higher required; version 7.21.1 or higher recommended) may be used if desired.
On Python 2.5, PycURL is required, along with simplejson and the Python development headers (typically obtained by installing a package named something like python-dev from your operating system).
On Python 3.2, the distribute package is required. Note that Python 3 support is relatively new and may have bugs.
Tornado should run on any Unix-like platform, although for the best performance and scalability only Linux and BSD (including BSD derivatives like Mac OS X) are recommended.