Free

TraceKnack is a Python module to assist in debugging Web Applications. It's designed to drop cleanly in to most Web Frameworks, catching exceptions and displaying a simple interactive debugger in your web browser.

TraceKnack gives you full access to the guts of your application, over the wire. For this reason, it is obviously recommended only for development servers, not production ones that the public has access to.

TraceKnack:

• Allows you to browse up and down the call stack
• Displays a chunk of code (not just one line) around where the error occurred
• Applies syntax-highlighting to the source code
• Displays a complete list of local variables for each stack frame, with their types and values
• Using AJAX, you can open up compound structures, to see the elements of a list, keys and values of a dictionary, members of a class, and so on. Each of those can, in turn, be explored.
• Functions and private members are hidden by default, to reduce clutter, but can be toggled back on when needed.
• You can also browse up to the global variables, and from there, explore pretty much the entire state of your code.

TraceKnack is free to use and generously licensed. If TraceKnack saves your ass on a project, please let us know, drop us a link, or give us a friendly mention on your blog. Thanks!