Is the monthly percentage of profits that a friend working in supplies gives as a result of solving a problem between my company and his company considered a bribe, knowing that my work is in sales and does not affect the purchasing department, and is it permissible or forbidden?

The question involves two matters: the ruling on taking a commission for brokerage, and the ruling on this commission being a percentage of the profit.

Firstly: The ruling on taking a commission for brokerage: If the brokerage takes place outside working hours: It is permissible to take the commission from one party or from both parties, because this time belongs to you. If the brokerage takes place during working hours: It is not permissible except with the company's permission, because you are a private employee.

Secondly: The ruling on the commission being a percentage of the profit: The view of the majority of scholars: It is not permissible, because the commission (ju'alah) must be known, and a share of the profit is unknown. The Prophet, peace be upon him, forbade hiring a worker until his wage is made clear to him. The view of some scholars (which is well-known from Imam Ahmad): It is permissible, citing the permissibility of giving a garment to someone who sews it or yarn to someone who weaves it for a known portion of the profit. In the event that the transaction is void due to unknown wages: You are only entitled to the wage of the like (ujrat al-mithl), and it is not permissible to exceed that.