You can debug your NinjaScript objects using Microsoft Visual Studio 2005 or higher.
1. In the NinjaScript Editor enable "Debug Mode"
2. From within Microsoft Visual Studio select Debug > Attach to Process... and select NinjaTrader from the process list and press the "Attach" button
3. Open the NinjaScript source file within Microsoft Visual Studio and set your break point(s)
4. Run your NinjaScript object in NinjaTrader and it should stop at your break points and all the debugging tools and information should be available to inspect the current state of the code.