Tornado is an open source version of the scalable, non-blocking web server and tools that power FriendFeed.

The FriendFeed application is written using a web framework that looks a bit like web.py or Google’s webapp, but with additional tools and optimizations to take advantage of the underlying non-blocking infrastructure.

The framework is distinct from most mainstream web server frameworks (and certainly most Python frameworks) because it is non-blocking and reasonably fast. It can handle thousands of simultaneous standing connections, which means it is ideal for real-time web services.

Tornado has been tested on Python 2.5 and 2.6. To use all of the features of Tornado, you need to have PycURL and (for Python 2.5 only) simplejson installed.