Quote from dandxg:
Use the search in the top right, been covered many times.
FYI, futures fx trade a centralized market place, forex is typically against your broker, unless you trade enough size to trade against big banks.
If you trade size and can trade against real banks, not your broker, there may be more volume on spot fx, but that's questionable.
Forex is a casino in most cases, unregulated for the most part.
It's much easier, due to lack of regulation, to have your broker go under and you lose your money, adios. It's changing, but slowly.