Designing a kill switch that actually works

[Shadow Trader]

A kill switch is an emergency stop: one action that closes everything and prevents further trading. It sounds simple, and the details matter.

Questions to settle in advance. What does it close: open positions, pending orders, or both? Does it work if the main platform is frozen? Is there a second route, such as a mobile app or the broker's web terminal? Who can trigger it, and from where?

On the software side, a bot can check a flag file or a remote setting every few seconds. When the flag changes, it closes positions and exits. That allows a stop from any device with access to the flag.

Testing is essential. A kill switch never tried on demo is a hope. Running the drill every couple of months, including with the platform deliberately sluggish, reveals gaps.

Also useful: a written emergency card with the broker's dealing desk number and login details for backup access.

Is a kill switch in place, and when was it last tested for real?