If you cast your mind back at least six years ago, there were only a small handful of software utilities to compare Excel workbooks. Typically even for average sized workbooks they took at least ten minutes. Worse than that some of them even failed to spot all the differences. All these Excel compare utilities were written as Excel add-ins, meaning they ran inside Microsoft Excel and were invoked from its menu system.

We did not want to do the exact same thing again. We decided to write DiffEngineX as an desktop application running outside of Microsoft Excel. This way it would be a little easier to invoke it from the command line with arguments or from source control systems.

With the benefit of time, we realized an almost arbitrary decision was fortuitous. When Microsoft released new versions of their runtimes and libraries, Excel add-ins broke. When Microsoft released 64-bit operating systems, Excel add-ins broke. DiffEngineX runs outside Excel and it kept on working despite all Microsoft's changes. DiffEngineX has been the compare utility that people turn to when everything else fails to work.

DiffEngineX was one of the first Excel compare utilities to report all the differences between two medium sized Excel workbooks within tens of seconds rather than tens of minutes.

The early versions of DiffEngineX were only intended as a minimal implementation of the classic diff algorithm i.e. software to point out the similarities between two sequences of information. Over time with customer feedback DiffEngineX has grown into the application it is today.