Tornado comes with limited support for WSGI. However, since WSGI does not support non-blocking requests, you cannot use any of the asynchronous/non-blocking features of Tornado in your application if you choose to use WSGI instead of Tornado's HTTP server. Some of the features that are not available in WSGI applications: @tornado.web.asynchronous, the httpclient module, and the auth module.
in other words: WSGI sucks
Smisk is a simple, high-performance and scalable web service framework written in C, but controlled by Python. Smisk is currently used in production by Spotify and Livebloggen.
Can work on WSGI application, thanks Spotify!
Werkzeug, the swiss army knife for Python web developers.
the WSGI anti-framework