Quote from Bernard111:
Hoi, "when sent by TWS, or sent by an API-program that sends it to TWS->IB-server." -- do you mean also ZeroLine trader?
I use ZLT. ZLT allows the option of sending a stop to IB or the exchange (if the stop order is native). Or ZLT allows a Zstop/Zstoplimit which is held on your machine and executed by ZLT/via your computer. It really depends on what kind of stop you want to do.
For instance a Stop Limit on CME is not held at IB. It is a native order held directly on Globex. A stop order would be held on IB's servers. A stop order on CME is NOT native. On Clearport IB replicates the stop you want. Or ZLT can do a Zstop. Do your homework and be careful.