I copied the following from the Waka Waka website!
Does your EA support FIFO?
The EA itself supports FIFO without problems, so there are no problems in principle here. However, most of the brokers available in the USA provide terrible trading conditions, so profitable scalping is only possible with a few of the US brokers.
I spent a good deal of time testing brokers available for US citizens and so far found only two brokers with trading conditions that allow scalping to be profitable: Oanda and Coinexx. Oanda is heavily regulated, but with worse trading conditions compared to top choices like IC Markets, Pepperstone, RannForex.
I estimate that with risks of 0.01 lot per $100 of your deposit one can have about 50% made per the average year with Oanda (while it is about 100% with other brokers listed above). The other 50% will be eaten away by higher spreads, slippages and commissions. Now, Coinexx provides good trading conditions comparable to IC Markets. But it is an offshore broker, so not everyone will be comfortable working with it