Is it permissible to purchase online using credit cards without hand-to-hand exchange of currencies, and is the commission that the bank takes for this service permissible?

It is permissible to use unsecured credit cards if they do not involve usurious interest, provided that a fixed fee is paid upon issuance or renewal.

If the card is permissible, it is permissible to make purchases with it from websites, even if the currencies differ, as long as there is a constructive قبض (possession), such as a bank entry.

If the bank changes the exchange rate and sells the currency at a higher price, there is no harm in that if the constructive قبض occurs by deducting the counter-value from the cardholder's account, because the increase is not influential as long as the two currencies are different, or if the bank pays the foreign currency on behalf of the cardholder as a loan and then collects it from him in another currency at the rate of the payment day. However, if the bank settles the price as a currency exchange (sarf) and does not determine the amount of the बदले (substitute) until the day of payment, then it is not permissible.

There is no harm in the commission that the bank takes, whether from the seller or the buyer, if the card is secured. However, if it is unsecured, it is not permissible to take an additional amount other than the issuance or renewal fees from the cardholder, as this is considered usury.