What is the ruling on working to promote and install credit card machines for restaurants that serve pork, and for supermarkets that sell cigarettes and alcohol, knowing that the company takes a percentage of the income of these establishments and gives me a percentage of that percentage?

It is permissible for shops and restaurants to deal with credit card devices, and the sin for this falls upon the buyer, the cardholder, if it is interest-based. It is permissible to promote these devices to those who use them for permissible things, but it is not permissible to promote them to those who use them for forbidden things. If a restaurant sells both permissible and forbidden items, it is permissible to provide it with the device, while disposing of the money that corresponds to the sale of forbidden items. It is permissible for the fee for using the devices to be a percentage of what is sold through them, according to the Hanbalis, in contrast to the majority.