Copy trading
Copy trading uses software to mirror the trades of one account onto another automatically — another trader's account, a paid signal service, or a second account of your own.
In retail trading it is a product: platforms let users allocate money to a strategy provider and replicate every position. In the prop world the term mostly appears in rulebooks, because firms draw a hard line through the middle of it. Copying between your own accounts — including accounts at different firms running the same strategy — is commonly permitted; copying anyone else, whether a signal group, a paid "pass service", or another trader, is commonly prohibited.
The rationale is that an evaluation certifies you. A thousand accounts running identical third-party order flow tell the firm nothing about any individual, and paid pass services sell exactly that. Firms compare order timing across their client base and against known signal feeds; matches commonly surface at payout review, where the applied penalties are denied payouts, voided profits, or closure — a conduct-based account breach without any loss limit being touched.
In a prop-firm challenge
Paying a service to copy-trade you through a challenge is against most firms' terms even when it works: the account is typically voided at review, and bans commonly extend across a firm's related brands. Which copying arrangements survive scrutiny, and which clauses cover them, is part of prop firm rules explained.