Maybe I'm missing something really obvious, but I don't understand where Flask fits into the picture. The article seems to introduce the first few steps of how you can debug any Python with pdb, not just Flask applications.

Try "pudb" instead of "pdb" if you want a fullscreen debugger.

http://pypi.python.org/pypi/pudb

Also, agreed with tomlu -- this will work for any python app (as long as it doesn't do strange things to stdout -- nose and daemons are probably the most common examples of things that do change stdout).

I tend to use pdb like this a lot. I write about as much of a piece of code as is obvious and then have it drop into pdb. I can then look around and play around with what I could do next.