What is the ruling on working in programming software for companies that use it in activities related to tobacco, such as documentary credit programs for salaries?

Selling software to a company that sells tobacco, and working for this company in the future, is impermissible because it is assisting in sin. Therefore, repentance for what has passed is obligatory, and one must not return to it.

As for the money received for it, what is permissible from it is the equivalent of the software's price if it were sold to someone who would use it for permissible purposes. Any excess should be given in charity because it is an unlawful price. Some scholars have gone further, stating that the entire price should be given in charity.