Yes, we've updated to the latest Rithmic API, so we do support server side OCO for Rithmic. Their new API also allows us to offer our Market By Order feature.
We do not have an app for Rithmic, but this may work as back up on mobile https://trade.optimusfutures.com/, not an app but could be used on mobile.
This is the technology we used. Except they are not brokers, so I have no clue why he did not refer to me.