Risk & safety · updated 2026

The engine command strip, explained

Every engine control lives in one place: the command strip at the top of the trading pages, Trade Desk, Accounts, Copy Rules and Risk Management. It is the same strip on each of them: a state dot and the status word on the left, then only the button that applies right now, a thin divider, and Flatten all. There are no engine controls anywhere else (your Overview start screen links to these pages rather than carrying a strip of its own), so you never have to hunt for the off switch. Every strip drives the same engine: your own copier, which no other customer's actions can stop or flatten.

On a phone the strip is shorter on some tabs. The Desk and Rules tabs carry it in full, Risk keeps the state and Flatten all (plus Resume copying while copying is paused), and Accounts leaves it out. Start and Stop are always one tap away on the Desk tab.

Which button you see

The strip only shows a button that can act right now. While the copier is stopped you see Start copying. While it runs, starts or reconnects you see Stop. After Flatten all has paused copying, Resume copying appears beside Stop. Flatten all is always there, after the divider. For a moment after you open the app, before it has heard from the copier, the strip shows no Start or Stop button (only a faded Flatten all) rather than a wrong one.

Start copying

The blue button, shown while the copier is stopped. From the moment you press it, every leader fill places real orders on your follower accounts. It looks faded until there is something to copy: at least one broker connection switched on, and a saved copy group with a leader. Press it while it is faded and a message says which step is missing. It will not start half-configured.

Stop

Shown while the copier runs. Copying stops immediately. Open positions stay open on every account. Nothing is closed. Stop is for "stop mirroring new fills", not for "get me flat". If you want flat, that is the next button.

Flatten all

The outlined red button, always on the strip. One click closes every open position (the leader's as well as the followers') at market, and pauses copying until you press Resume copying. It is faded when nothing is open, so you can read its state as "is anything at risk right now". Full detail in the Flatten all kill switch.

Resume copying

Shown beside Stop after Flatten all, or a leader's risk limit, has paused copying, including while a connection is reconnecting. It re-enables every group, including a group that stopped itself because its leader hit a risk limit. If a leader's own limit paused its group, that leader is also locked: unlock it on Risk Management first, or the group still copies nothing after Resume copying. After a full flatten, Resume copying re-opens nothing: the leader is flat, so there is nothing left to copy. The engine reconciles from the broker's live book and waits for the next fill.

When the copier stops without you

Four things other than your own Stop can stop your copier, and each one tells you:

• The broker signed the login out because the same login connected somewhere else (Rithmic or Volumetrica). The strip reads an amber Stopped, a toast stays on screen until you close it, and the forced-logout alert goes out. See what happens on a disconnect.
• Your plan no longer covers copying: it was cancelled and the paid period ended, a failed payment ran past its grace period, or a downgrade left your setup bigger than the new plan. The copier stops within about a minute and a Plan limit message says which. See payment failures and the grace period and plans and account limits.
• MirrorFill support stopped it. The strip reads an amber Stopped, Order history records "MirrorFill support stopped this copier.", and the copier-stopped alert arrives titled "Your copier was stopped by support" if you have that alert on. If you did not expect it, contact us.
• The MirrorFill server restarted, for example for an update. Your copier stops with it and does not start again by itself: the strip reads Stopped, and a planned restart sends the copier-stopped alert (a crash cannot send anything, see notifications and alerts). When you press Start copying, your positions are read back from the broker, not re-traded (see restarting while positions are open).

Each is an ordinary stop: open positions stay open at your broker, and nothing in your setup changes. Press Start copying when you're ready (once the plan is sorted, in the second case).

One click by default

Every button acts on a single click. There is no arming stage and no typed confirmation. If you want a second look before the big ones, the Risk Management page has three opt-in switches: Ask before Flatten all, Ask before Start copying, and Ask before Stop, under Confirmations (a fold on a phone). They are off by default and apply in that browser only.

Using Flatten all, or the copier stopping for any reason, also raises an alert: an e-mail or Telegram message if you have those on (Flatten all also answers with a toast on screen). That is deliberate: an engine that stops while you are away from the screen is exactly the thing you would want to be told about. See notifications and alerts.

Quick answers