Copying between two accounts on the same platform, at the same broker, is close to a solved problem. Copying from MetaTrader 5 to cTrader — or to MT4, or across two brokers who each have their own instrument catalogue — is where the interesting failures live.
None of them are exotic. They are all mismatches between two systems that describe the same market in different words.
Symbols are not standardised
The euro against the dollar might be EURUSD, EURUSD.r, EURUSD_SB, EURUSD-ECN or EUR/USD depending on the broker and the account type. Suffixes encode the pricing model, and brokers do not agree on them.
A copier therefore needs a mapping, and the failure mode when it lacks one is binary: the trade is either skipped or rejected. That is the good case — loud and immediate.
The bad case is a mapping that resolves to the wrong instrument. Indices and commodities are where this bites: US30, DJ30, WS30 and USA30 are the same underlying at four brokers, but GOLD and XAUUSD are occasionally not the same contract size at the same broker. Which brings us to the next one.
Contract sizes differ, so "one lot" is not one thing
One lot of EURUSD is 100,000 units almost everywhere. One lot of gold is 100 ounces at most brokers and 10 at some. One lot of an index CFD is whatever the broker decided.
If a copier translates volume without normalising for contract size, a correct-looking 1:1 copy can be a 10x position. This is the single most expensive cross-platform mistake, and it is invisible in the trade log — the lot numbers match perfectly.
Check it directly: open a small position on the same instrument on both accounts and compare the notional value, not the lot size. If they differ, the mapping needs a volume factor and you have just saved yourself a very bad afternoon.
Filling modes and order types do not map cleanly
MT5 has Fill-or-Kill, Immediate-or-Cancel, and Return. cTrader's model is different again, and MT4 has none of this. A partial fill on the master can become a full fill, a rejected order, or two separate positions on the follower, depending on the pair.
The practical consequences:
- A partially filled master order may copy at full size, or not at all.
- Position accounting differs — MT5 can net positions per symbol while cTrader keeps them separate, so "close the position" means different things.
- Some brokers reject market orders entirely during news windows, and the copier's retry behaviour then decides whether you get a late fill or none.
Stops, levels and the trades that get rejected
Brokers enforce a minimum distance between the market price and any stop or limit. If the master's broker allows a 2-pip stop and the follower's requires 10, that copied order is rejected — and rejected after the position opened, if stops are attached in a second step.
That leaves the follower holding an unprotected position. It is the most dangerous state in cross-platform copying, and it is worth knowing your copier's answer in advance: does it close the position, retry at the minimum allowed distance, or leave it open and warn?
Ask what happens to a position whose stop was rejected. The answer separates tools that are safe to leave running from tools that need supervision.
Before you go live
- Map every instrument you actually trade, and verify each one by notional value rather than lot size.
- Run a demo follower on the target platform for at least a full week of your normal trading.
- Deliberately test the ugly cases: a partial fill, a very tight stop, a partial close, and a trade during a news release.
- Confirm that rejections reach you as alerts rather than as log lines nobody reads.
- Only then attach a live account, and start at a fraction of intended size.
Cross-platform copying works well once the mapping is right. Almost every horror story is a mapping that was assumed rather than verified — and the verification is an afternoon of work against instruments you already trade.
