I have a project for making electronic programs which transmit information on riba-based loans between banks, so that they can find out about the loans that a person has taken out before giving him a riba-based loan. But this program does other things besides that. Is this permissible?.
If this program can be used by the riba-based banks to get information about those to whom they are going to give riba-based loans, then it is not permissible to sell it to them, or to work on it, because that is helping in sin and transgression, and Allaah, may He be exalted, says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment”
And the Prophet (blessings and peace of Allaah be upon him) said: “Whoever calls to misguidance will have a burden of sin like that of those who follow him, without that detracting from their burden in the slightest.” Narrated by Muslim (4831).
There is a stern warning concerning riba, and curses for those who do it, write it down and witness it; this is a deterrent to every wise person from getting involved in it or helping in it.
Allaah, may He be exalted, says (interpretation of the meaning):
“O you who believe! Fear Allaah and give up what remains (due to you) from Ribaa (from now onward) if you are (really) believers.
279. And if you do not do it, then take a notice of war from Allaah and His Messenger but if you repent, you shall have your capital sums. Deal not unjustly (by asking more than your capital sums), and you shall not be dealt with unjustly (by receiving less than your capital sums)”
and Muslim (1598) narrated that Jaabir (may Allaah be pleased with him) said: The Messenger of Allaah (blessings and peace of Allaah be upon him) cursed the one who consumes riba and the one who pays it, the one who writes it down and the two who witness it, and he said: they are all the same.
So beware lest you be helping in this grave sin.
We ask Allaah to protect you against that and to make it easy for you to find halaal and blessed ways of earning a living.
And Allaah knows best.