Question:
I'm hiring a non Jew online to do some word processing work. He says he can get it done by Saturday which means he might work on Shabbos although he can get it done earlier if he wants. Am I allowed to do this?
Answer:
If he can get it done in a reasonable way (not by working crazy hours) before shabbos then it is permitted, since he chose to do it on shabbos for his own benefit. However if it is not reasonable for him to get it done before shabbos, then you have to leave him some time to get it done after shabbos. Alternatively, if you tell him to have it done by Sunday, and he got it done beforehand, even if he did the work on shabbos it would be permitted, since he chose to do it then.
Sources:
O:CH 264-1, M:B -4.