+1 ------- Only thing you can do is Adjust your position SIZE, Intraday or on 4H / 8H. time frame to maximize Profit. Goodluck.
-1 It can be done. Trend, counter trend < daily bars. Combine many strats and pairs, keep correlations minimal for the timeframes considered, keep bets small to allow for when non correlated strats become correlated (they will). I agree you cannot beat the banks everyday, but if you can go thru periods days/ weeks in drawdown then you can come out ahead. Personally I cannot win everyday, so I don't even try, but I can say that you must always let your tested ideas run (Automated) all the time.
I suggest http://www.lmaxtrader.co.uk/ (relatively well-regulated real marketplace with sometimes low spreads, low startup costs and a free API with TCP/IP interface) and http://esper.codehaus.org (NEsper if you don't want to use Java). This should be enough to cover all needs.
http://www.lmaxtrader.co.uk/apply-for-an-account "Please note we are unable to accept applications from US residents." That's a shame... Another option is Dukascopy, with a $1000 minimum opening balance. However, their API is a Java one: http://www.dukascopy.com/swiss/english/forex/jforex/library/ Another option is to use MBTrading's FIX interface (as one of the few retail brokers, TCP/IP based) - http://www.mbtrading.com/developersMbtFixGateway.aspx . However, it's unclear if it can be used for trading FX. Also see http://fixprotocol.org . And unfortunately, that's basically it, in retail land... Of course there's MetaTrader (http://www.metatrader5.com/ or -4.com), but it's not really as "custom" as you want it.
There's also http://www.forex.com/forex-api.html , but the list of bad reviews of forex.com/GAIN capital is quite large, the question is if you want to associate yourself with them.
The OP needs to answer this question for himself: What Competitive Advantage do you have... Over bank traders with decades of experience... And multi-million $$$ tech budgets... And access to large quantities of Inside Information? And also the converse question... What Competitive Disadvantages do you have? I've been running a trading business for 15 years... Because I can give very specific answers in this regard. It all boils down to this.
what would a messaging mechanism provide for this? I do use a messaging but its not needed for order handling
I like to discuss only the bad scenario. so, if all correlated " I agree 100% this will happen, and maybe the first hour you trade ". Do you think that starting small is the major defense? if not, how will you deal with?