Hi all, I am developing my high speed trading platform. However, I would like to know if there are good open source high speed trading platform so that I can avoid reinventing the wheel. My questions are: 1. For order execution, is FIX the most popular (standard) approach? 2. For order management, what's the best method to handle that? Let's say you want to submit long/short orders to maintain market neutrality, what if one of the order gets executed and the other side doesn't so the legs are broken? How to manage these types of situation? 3. What's the best approach to incorporate a backtest platform to seamlessly connect to the execution and order management? Any thoughts? Thanks a lot!