Kindly refer to the following link(s):


It is not permissible to trade in currency except if the transaction is done on the same spot and time by giving the money and receiving it hand by hand at the same time. In Forex, you need a day or two before you can cash your money, if I am not mistaken.


Ruling of Forex trading in Islam


Currency Trading: Buying Foreign Currency and exchanging it later for higher rate 


https://islamqa.info/en/answers/106094/ruling-on-dealing-in-currencies-in-the-forex-system-and-paying-fees-for-delaying-the-deal





And Allah Knows Best