Your analysis of Tornado is unfair. It offers easy ways to throw specific HTTPErrors, and those are handled exactly as they should be. If you throw an exception

Your analysis of Tornado is unfair. It offers easy ways to throw specific HTTPErrors, and those are handled exactly as they should be. If you throw an exception that Tornado doesn't know about, then it simply by default notifies the user that an internal server error occurred. It is extremely easy to design your code to throw the right http exceptions, and it is just as easy to write your own custom python exceptions that cooperate with their stack. You most certainly don't have to modify the framework itself, and tornado is designed specifically to be easy to extend.