`Tornado`_ is an open source version of the scalable, non-blocking web server and tools that power `FriendFeed`_.
Because it is non-blocking and uses epoll, it can handle thousands of simultaneous standing connections, which means it is ideal for real-time web services.
Integrating this service with Flask is a trivial task::
from tornado.wsgi import WSGIContainer
from tornado.httpserver import HTTPServer
from tornado.ioloop import IOLoop
from yourapplication import app
http_server = HTTPServer(WSGIContainer(app))
http_server.listen(5000)
IOLoop.instance().start()
.._Tornado: http://www.tornadoweb.org/
.._FriendFeed: http://friendfeed.com/
Gevent
-------
`Gevent`_ is a coroutine-based Python networking library that uses `greenlet`_ to provide a high-level synchronous API on top of `libevent`_ event loop::