Is my job as a bank employee forbidden or permissible (haram or halal)?

It is not permissible to work in interest-based (usurious) banks, due to the involvement in consuming usury, or authorizing it, or writing it down, or bearing witness to it. All of these fall under thecursion of the Messenger, peace and blessings be upon him, upon the one who consumes usury, its authorizer, its scribe, and its two witnesses.

Even if the worker is not directly involved in these roles, he is still assisting in sin and transgression, and Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."