Praise be to Allaah.
It is not permissible to offer assistance or services or
programming to riba-based banks or companies that produce alcohol, because
that is helping in sin and transgression, and Allah 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”
[al-Maa’idah 5:2].
The one who helps another to do evil or shows him the way to
it is a partner in the sin and has failed to do what Allah has enjoined of
denouncing and disavowing evil.
Thus you know that it is not permissible to contribute to
maintenance or programming that has to do with these haraam companies,
whether that is done regularly or rarely. If you know that a client has a
company that does haraam things, it is not permissible to you to provide
services to him.
There is nothing wrong with you remaining in your job if you
can avoid participating in haraam work. But if you can find another job that
is free of the things we have mentioned, then that is better.
See also the answer to questions no.
85441 and
102923
And Allah knows best.