What is the ruling on taking a 2% fee in exchange for the mediation of a website for selling virtual products, with a guarantee of the buyer's rights, and does the ruling change if the transaction is conducted with currencies, and is it permissible to deal with these websites?

It is permissible for the website to take a percentage or commission for its agency on behalf of the seller in receiving the price, and on behalf of the buyer in delivering it, because it is permissible to take a fee for agency. As for currency exchange transactions, it is stipulated that possession must take place in the contracting session. If this condition is violated and the transaction becomes invalid, then intermediation and taking a commission are not permissible, due to the assistance in sin involved therein.