Python 3 has been out for a while, but many companies haven’t yet found a compelling reason to move from Python 2. One feature which has been getting a growing amount of attention, and which is encouraging people to move to Python 3, is asyncio — a part of the standard library as of Python 3.4, which allows for asynchronous I/O. But what does “asynchronous I/O” mean, how does it relate to Python, and why would I want to use it? Moreover, how can I use it? In this talk, Anton Caceres introduces us to asynchronous Web development in Python, which is based on Python’s generators, and which offers a new way to think about Web applications.