I would like to volunteer writing binding for as many languages as you can come up with, but I can't guarantee I won't shave off a fraction of a cent in transactions. Or that I'll get the decimal placement right when dealing with that "fraction"...

In all seriousness, I would be fairly worried running someone else's code on my bank account unless it was very straightforward. Even forgoing malice and incompetence, there's plenty of "wow, that's a crazy interaction between systems that wasn't obvious" to go around.