Is it impermissible to work for a software company that is developing a program for a grocery store selling Danish products, knowing that Denmark has insulted the Prophet Muhammad, peace and blessings be upon him?

Allah has permitted Muslims to engage in buying and selling with non-believers, provided that the transaction is not related to something forbidden. The Prophet, peace and blessings be upon him, and his companions interacted with them. If Muslims see a legitimate benefit in boycotting the goods of non-believers economically, they must adhere to it. Therefore, if the program you are assigned promotes or assists in promoting goods that scholars deem beneficial to boycott, then it is not permissible for you to work on it. However, if the program has no relation to what has been decided to be boycotted, and there is no assistance in sin and aggression in it, then there is no objection to working on it.