I'm a heavy user of the excellent Visual Studio debugger for C++ and C#. But for years I didn't use an IDE or debugger for server side Python; I did a lot of Zope & Django debugging with print statements and log files. A couple of years ago I started using IDEA's PyCharm. It's massively accelerated how quickly I can fix bugs in Tornado based server code. More recently I've switched my server side coding style to use coroutines, and that requires a shift in debugging mindset as one can't make the same control flow assumptions as for conventional callback style single threaded async code. I'm looking forward to debuggers that understand how to step over yield or await.