A complete free of setup fees and accessible for everyone FIX API implementation is e.g. offered by fxpig.com. I don't know how reliable they are but this shouldn't matter if they provide a FIX API playground ... demo account I mean.
Wow, you're right. I can't open live accounts with them but they let me open a FIX demo anyways. How nice.
So they do FIX 4.4, which is relatively common. I am uncertain of how much tinkering is required to make the messages compatible with an individual broker - hopefully this is minimal.
What I might have to do is make a FIX 4.4 plugin and require a certain BrokerCommand or username "flag" to enforce message compatibility (i.e. BrokerCommand(SET_BROKER,BROKER_FXPIG)).
To be honest, this is low priority on my own list, but maybe I can get to it within a year.
