When I do my editing, some questions come up repeatedly. One frequent question is why MS Word spellcheck will allow both “programing” and “programming” in US English without a squiggly red line for either.

Because I’m somewhat obsessive in my editing, I searched for a “definitive” answer for what is “correct” or “preferred”.

I feel that the link below gives a good explanation, with reasoning.

“Programming” versus “programing”: which is preferred?

SPOILER ALERT: “Programming” is probably preferred..AP Style may differ.