How a trade copier works
A trade copier watches one trading account, the master, and places the same trades on one or more other accounts, the followers. When the master opens, changes or closes a trade, the copier does the same on each follower, usually within a second.
1. Watching the master
The copier needs to see the master's trades the moment they happen. On cTrader this is done through cTrader's official connection with read-only access: the copier can see trades but can't place any or touch money on the master. On MT4 and MT5 a small program (an "EA") runs inside the terminal and reports each change.
2. Deciding the size
A follower with $500 shouldn't trade the same lots as a master with $50,000. Copiers size each copy using a rule you choose:
- Same lots: the follower trades exactly the master's size.
- Ratio: for example half the master's size.
- By balance: in proportion to the two accounts' balances.
- By risk %: each trade risks the same % of the follower's balance, based on the stop loss.
3. Placing the copy
The copier places the trade on the follower's account at its broker, with the stop loss and take profit. If brokers name the symbol differently (XAUUSD at one, GOLD at another), symbol mapping translates it.
4. Following every change
Moving the stop loss, closing half, closing the rest: each is copied. A good copier remembers which follower trade belongs to which master trade, even after a restart, so closes always go to the right trade.
5. Safety limits
Because a copier acts automatically, limits matter: a daily loss limit, an equity stop, caps on lot size and open trades. They stop new copies when a follower has taken enough risk.
What can go wrong
- Slippage: the follower's price can differ slightly from the master's, especially in fast markets.
- Broker rejections: a follower's broker may refuse a size below its minimum, or a trade outside its hours.
- Connection: MT4/MT5 terminals must be running; if one is closed, its account stops copying.