What is the ruling on creating services and auxiliary programs for usurious banks, especially if they are specific to the loans department, and what is the ruling on the programmer and administrative manager participating in that, and what is the ruling if the bank is Islamic?

It is not permissible to assist an interest-based bank by producing programs that help it in its forbidden transactions, because that is considered cooperation in sin and aggression. The Prophet, peace and blessings be upon him, cursed the one who consumes interest, the one who pays it, its scribe, and its two witnesses. However, if the bank is Islamic, there is no harm in creating programs for it to be used in its Sharia-compliant transactions.