Is it permissible to employ workers in an institution for a lump sum fee that they pay me at the end of the month, with their consent to that?

It is not permissible to take sums of money from workers because such dealings involve gharar (definition) (excessive uncertainty), which is prohibited by Islamic law. Furthermore, an unspecified fee for an unknown duration is not permissible. However, it is permissible to take a known fee paid either in a single installment or in installments. Attention must be paid to Islamic transgressions, poor treatment, and the unlawful seizure of people's rights in such work and contracts.