A currency future contract is an agreement to buy or sell a currency under an organized exchange i.e. the futures market. Advantage of futures is that there is a central market for futures. There is no chance for any default also. Since the currency future is traded in the stock exchange there is high liquidity for the contract. Difference between the currency forward and currency future is that the former is a bilateral contract not involving a stock exchange, the latter is derivative contract undertaken in a stock exchange. The contract under futures has tradability also; while there is no tradability under a currency forward.
