What is the ruling on programming pages and codes related to credit card purchase services from usurious banks, and is it obligatory to avoid working on any website that provides this service, or only the sections related to it? What is the ruling on continuing to work for a company that contracts with entities that deal with usury? And what is the ruling on creating a general code library that may later be used on prohibited websites?

It is permissible to use credit cards (Visa) for buying and selling if they are free from Shariah prohibitions. There is no objection to designing permissible websites that provide online shopping services. It is permissible for the seller to sell to someone who uses a Visa card without asking about the details of its usage, unless the sale is for something forbidden. It is not permissible for a designer or programmer to assist in anything forbidden. It is permissible to work in companies that use Visa cards, provided that one does not assist in anything unlawful. There is no objection to creating a library of codes that can be used later in e-commerce websites or for dealing with banks and hotels.