Auto Trade Copier: Mapping, Sizing and Failure Tests
Plan how an automatic trade copier translates an instruction into a follower order, then test sizing, state and recovery before enabling it.
Trace one instruction end to end
A copier receives a source instruction and turns it into an action in another account. Record the source trade identifier, destination account, instrument mapping, proposed quantity and final broker response. A connection indicator does not prove that this chain completed correctly. Keep the source and follower records so a missing, duplicate or altered instruction can be reconciled.
Translate exposure rather than copying a lot number
Instrument names, contract sizes and account currencies can differ. A source order of one lot is not a universal amount of exposure. Specify the sizing rule and its required inputs: fixed quantity, a multiplier, equity proportion or another documented model. Then apply destination minimum size, step and exposure limits.
For a fictional same-contract example, a 10,000-equity source with 0.20 lots and a 5,000-equity follower implies 0.10 lots under a simple equity-proportional rule. That arithmetic assumes matching contracts and currencies and does not establish matching risk or a suitable trade.
Create a test matrix
| Case | Evidence to retain |
|---|---|
| Open, modify, partially close, close | Matched source/follower identifiers and quantities |
| Unsupported symbol or minimum size | Explicit rejection or documented rounding |
| Disconnect and reconnect | Defined stale-message and retry behavior |
| Restart with open positions | No unexplained duplicate or orphan position |
| Follower rejects an order | Alert and a documented reconciliation action |
Define stopping and recovery
Stopping new copies, cancelling pending orders and closing positions are different operations. Identify which action an emergency control performs. Rehearse recovery in a test environment, including who owns an already-open follower position after copying is disabled. A copier should not silently “catch up” with an old instruction unless that behavior is explicitly intended.
Know the scope of the test
This is an implementation checklist, not a product endorsement or measured latency comparison. Demo results do not guarantee live fills. Provider documentation can explain configuration, but the actual broker, account and symbol mapping must be checked in the intended environment.
Related guides and tools
Sources and scope
Primary documentation checked 2026-10-16. This original guide does not reproduce the former page or claim an original product trial, audited return or professional financial review.