All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is impermissible to participate in building or providing electricity systems, computer systems, monitoring systems, and the like to places whose original intended benefit is unlawful, such as usurious banks and pagan places of worship because this is an act of cooperating in sin. Allah, the Almighty, says: {…but do not cooperate in sin and aggression.} [Quran 5: 2]
The Messenger of Allah, sallallahu 'alayhi wa sallam, cursed the one who records it (Riba), the two who witness it (its transaction). He said: “All of them are equal (in sin).” [Muslim] An-Nawawi stated in his commentary on Sahih Muslim: “This indicates the prohibition of helping people in falsehood.” [End quote]
Accordingly, it is not permissible for the employer to accept applications for working in such places, and the employee may continue working in his company, provided that he does not participate in unlawful works, such as works related to usurious banks, pagan places of worship, and the like. He may only participate in other lawful works.
As for places whose original intended benefit is lawful, such as the benefit of staying at a hotel, the basic principle is that it is permissible to build and provide them with the required utilities such as electricity systems, computer systems, monitoring systems, and the like.
Allah knows best.