To develop to the T4 FIX API, you need a dedicated SSL connection to a T4 FIX API server. Your FIX client will negotiate a socket TCP connection and authenticate login parameters. To assist in development, we can provide a FIX Simulator system with market depth and execution 24x5, regardless of real market hours. From the FIX API’s perspective, the FIX Simulator works exactly the same as a live FIX system. FIX Technology