Internal Program Version: tornado6  6.3.2

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. 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. We built the web server specifically to handle FriendFeed's real-time
features — every active user of FriendFeed maintains an open connection to the
FriendFeed servers. (For more information on scaling servers to support
thousands of clients, see The C10K problem.)

https://www.tornadoweb.org