I have built on an EA that trades Binary Options. I found it really quite difficult to get information from brokers on what MQL syntax to use to send binary option orders i.e. trade size, expiry times etc... I also couldn't find much info on the www about it either. I have put the code below, hope someone finds it useful....
OrderSend(Symbol(),OP_BUY,Lots, Bid,3,0,0,'BO exp:900', MagicNumber,0,DodgerBlue);
OrderSend(Symbol(),OP_SELL,Lots, Ask,3,0,0,'BO exp:900', MagicNumber,0,DeepPink);
Lots = 0.01 would be $10 trade size for example
BO exp:900 = Expiry time in seconds so 900 would be 15 mins