Kill switch (STOP and flatten)

A kill switch is the single control that halts automated trading immediately: it disarms the strategy so no further decision is sent, and it requests that every open position be flattened and every working order cancelled. It is a request to the broker, not a confirmation that the account is flat.

Senzoukria · Glossary · Updated September 2026

What happens when it is pressed

  • The strategy is disarmed at once; no decision computed after that moment leaves the machine.
  • Cancel requests are sent for the working orders the platform knows about.
  • A market order in the opposite direction is sent for each open position, sized to close it.
  • The state switches to stopped and stays there; nothing restarts on its own.

Why the word request matters

Between the click and a flat account sit the connection, the broker's order handling and the market. A cancel can arrive after the order filled. A closing market order can fill with slippage, partially, or be rejected during a halt. A disconnect at the wrong second can leave the machine believing an order was sent that never arrived. Because of this, a well-designed kill switch is followed by a verification step: the trader checks positions and working orders at the broker's own interface before releasing the stop. The application's view is a hypothesis until the broker confirms it.

Kill switch versus daily loss limit

A daily loss limit is a rule evaluated before each order: it refuses new exposure once the loss threshold is reached. A kill switch is a human action that ends everything, including exposure already open. The first prevents the next mistake; the second ends the current one. Neither replaces the other, and neither removes execution risk on the closing orders themselves.

In Senzoukria

In the "Autopilot" panel, the control is labelled "STOP — disarm and flatten". After it the badge reads "STOPPED" and the panel shows a verification message: check positions and working orders on the original broker account, cancel or flatten there if needed, because releasing STOP does not confirm a broker state or restart trading. While requests are pending the panel says so and asks you to wait, then to check the account again; "Release the stop" is only a manual reset and does not re-arm. For manual trading, a separate "Flatten all" button with the tooltip "Cancel all working orders and close all open positions" is available from any screen once a broker connection is ready, with a confirmation step; it never opens a position. The "Stop filled" voice clip announces a filled protective stop.

Common mistakes

  • Pressing STOP and walking away without checking the broker's positions.
  • Expecting STOP to undo a fill that already happened; it can only close the resulting position at market.
  • Assuming that releasing the stop restarts the strategy; arming is a separate action.
  • Relying on the kill switch during a disconnect; keep a written procedure and the broker's own interface at hand.

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Frequently asked questions

Does STOP guarantee that I am flat?
No. STOP sends cancel requests and closing market orders; whether they fill, at what price, and whether all of them arrived depends on the broker and the connection. The trader verifies positions and working orders at the broker before considering the account flat.
Is a kill switch the same as flatten?
They overlap. Flatten cancels working orders and closes positions and can be used at any time in manual trading. A kill switch does the same and additionally disarms the automated strategy so it cannot re-enter. In an armed autopilot, STOP is the kill switch; the Flatten button alone would not disarm.
Should a kill switch cancel orders or close positions first?
Cancelling working orders first avoids a resting entry filling after the position was closed, which would reopen exposure. In practice both requests are sent in quick succession, and the order of broker acknowledgements is not guaranteed, which is another reason to verify at the broker afterwards.

Keep reading

Strategy researchTest a trading strategy, from observation to challenge rulesDefine an observation, question it with the copilot, write a rule and explore costs, drawdown and fictional challenge limits in an interactive example.Quant · Start hereQuant trading for beginners: from idea to backtestDefine a testable rule, choose suitable data and evaluate later periods after costs.Order flow · HubOrder flow trading: the complete guideThe hub. What order flow is, what it shows — aggression, delta, imbalance, absorption, liquidity — and the tools that read it, each linked to a full guide.