Prop Firms and Expert Advisors: What the Rules Actually Say

Check the firm’s prohibited-strategies clause, not its “EAs allowed” badge. The two frequently disagree, and the clause is the one that decides whether your profits survive a payout review.

That’s the whole practical answer. The rest of this explains why it matters and what to look for.

Two different questions people are asking

“Can I run my EA on a funded account?” — a trader with an existing automated system, wanting to know if a firm will take them.

“Which EA will pass my challenge?” — someone looking for a tool to get through an evaluation.

The first is a legitimate question with a firm-by-firm answer. The second has an uncomfortable answer that I’ll get to at the end, and it’s the reason this search result is full of people selling things.

What firms actually prohibit

Almost no firm bans “automation” as a concept and leaves it there. What they ban is a list of behaviours, and EAs get caught by those behaviours rather than by being software.

The recurring prohibitions across the sector:

Latency and price-feed arbitrage. Exploiting the gap between a firm’s quoted price and the underlying market. Universally banned, and the one that most reliably triggers profit forfeiture rather than a simple account closure.

High-frequency and tick scalping. Usually enforced through a minimum hold time rather than a frequency cap — two minutes is common. An EA scalping in seconds breaches this on every trade regardless of what the firm says about automation.

Grid and martingale sizing. Adding to losers on a schedule. Extremely common in retail EAs, and specifically named by most firms.

Order flooding. High volumes of orders, or high order-to-fill ratios, that strain the firm’s infrastructure.

Copying the same system across multiple accounts. Even your own. This gets treated as account correlation rather than automation, and it’s covered in copy trading rules.

Any tool that places, modifies, closes or manages trades without you. This is the broadest clause and the one firms use when nothing more specific fits.

Notice that a perfectly ordinary trend-following EA — holding for hours, no grid, no martingale, one account — breaches none of those. Whether it’s allowed comes down to whether the firm has a blanket automation ban, which is a separate question.

The badge and the clause

Here’s the trap.

A firm’s marketing page says “EAs allowed”. Its terms and conditions ban grid, martingale, arbitrage, sub-two-minute holds and any tool that manages trades automatically. Both statements are on the same website. The second one is what gets enforced.

So “EAs allowed” in this sector often means “EAs allowed, provided they’re not the kind of EA most people are buying”. That’s not necessarily dishonest — a discretionary trader’s custom execution helper genuinely is different from a martingale grid bot — but it’s a distinction the marketing doesn’t draw and the contract does.

What to do about it: find the prohibited-practices or prohibited-strategies page, read the whole list, and check each item against what your system actually does. If a specific behaviour isn’t addressed, email support and keep the reply. A written answer from support is worth considerably more than a badge on a landing page when a payout is being reviewed.

Disallowed versus voided — the distinction that costs money

Traders conflate two outcomes that are not remotely equivalent.

Your account is closed. You breached a rule during an evaluation. You lose the fee. Annoying, cheap, done.

Your trades are voided. You traded a funded account, made money, requested a payout, and the review found prohibited activity. The profits are reversed. The account is terminated. You’ve now spent weeks of work and lost everything it produced.

The second outcome is the one that matters, and it happens at payout review rather than in real time. Firms generally don’t stop you as you go — they check when you ask for money. That delay is why people believe a strategy is fine right up until the moment it very expensively isn’t.

If you take one thing from this page: the absence of an immediate warning is not permission.

How firms detect automation

Not by scanning for software. By looking at your trade record.

Timing distributions. Human entries cluster irregularly. Automated ones show suspiciously regular intervals, or entries at consistent sub-second offsets from a price event.

Holding-period histograms. A cluster of positions held for 8–12 seconds is not a discretionary trader.

Identical positioning across accounts. Same instrument, same direction, same lot ratio, same second — across accounts that are supposedly independent.

Order-to-fill ratios. A lot of orders and few fills suggests a system probing rather than a person trading.

Reaction speed. Consistently entering within milliseconds of a tick is not achievable manually, and firms know what manual looks like.

This is worth understanding for a reason that isn’t about evasion. A legitimate manual trader can get flagged, particularly one who trades a very mechanical system at consistent times. If that’s you, keep records — screenshots, a trading journal, session recordings if you have them. Being able to demonstrate manual execution is far easier before a dispute than during one.

The challenge-passing EA question

There’s a large market in EAs sold specifically to pass prop firm evaluations. The search results for this topic are dominated by people selling them, including at least one site with a link profile that looks nothing like an organically popular website.

Two arguments, and I think both are decisive.

The economic one. If an EA reliably passed prop firm challenges, running it would be worth vastly more than selling it. A tool that turns a $500 fee into a $100,000 funded account with, say, a 60% success rate is a money printer. Nobody sells a money printer for $199. The ones being sold are the ones that don’t work reliably, and their backtests are trivially gameable — you can curve-fit any strategy to a specific ruleset after the fact.

The mechanical one. Most of these EAs use martingale or grid sizing under the hood, because that’s what produces a smooth equity curve in a backtest. Those are explicitly banned at essentially every firm. So even in the case where it passes, you’ve built your funded account on a strategy that gets voided at payout review.

Red flags on any EA vendor, if you’re evaluating one anyway:

• No verified live track record — backtests only, or a track record on a demo
• Marketed specifically as a “challenge passer” rather than as a trading strategy
• Any use of the word “guaranteed”
• A drawdown curve that never has a meaningful drawdown, which usually means position sizes escalating into losses
• No disclosure of the strategy’s actual logic

Where TraderScale stands

Directly, because the answer is a no and you should know before you buy.

TraderScale prohibits Expert Advisors, bots, scripts and trade copiers on every account type and every account size. All trading must be executed manually. That’s not a conditional badge — it’s the rule, and it applies to instant funding, one-step and two-step accounts alike.

Also relevant: a two-minute minimum hold on every position, a mandatory stop loss on every position, and prohibitions on arbitrage, high-frequency trading, news bracketing, martingale, grid trading and hedging the same instrument.

Two things TraderScale does permit that people often assume are banned:

Manual mirroring across your own accounts. You can trade identical setups on multiple accounts you own, provided you personally place every entry. What you can’t do is add the same asset to a second account while the first holds a floating loss, hold opposing directions on the same instrument across accounts, or use secondary accounts to extend exposure beyond limits.

Pre-approved calculation tools, with support authorisation. A position-size calculator isn’t a trade manager, and the distinction is recognised.

If you run an automated system, TraderScale is not the firm for you, and finding that out at a payout review would be the worst possible version of this conversation. Firms that permit automation exist — check their prohibited-strategies clauses carefully, because “allowed” varies enormously in what it covers.

Full detail is in the TraderScale automation policy.

Common questions

Do prop firms allow EAs?
Some do, some don’t, and many that say they do prohibit most common EA behaviours in their terms — grid, martingale, arbitrage and sub-minimum-hold scalping. TraderScale prohibits automation entirely. Always read the prohibited-strategies clause rather than relying on a marketing badge.

Can prop firms detect EA usage?
Yes, from the trade record rather than from your machine: timing regularity, holding-period clustering, reaction speed and order-to-fill ratios. Detection typically happens at payout review rather than in real time.

Do prop firms really pay when the trading came from an EA?
Where the firm permits automation and the EA doesn’t breach any specific prohibition, yes. Where the firm prohibits automation, a payout review that identifies it generally results in voided profits and a closed account, regardless of how well the system performed.

Is there an EA that passes prop firm challenges?
None that’s reliably demonstrated. The economic argument is that anyone with such a tool would run it rather than sell it, and most challenge-passing EAs use grid or martingale sizing that is separately prohibited at almost every firm.

What happens if I use a banned EA and get caught?
During an evaluation, the account is usually closed and the fee lost. On a funded account, it typically means forfeited profits and termination — and because the check happens at payout review, it usually surfaces after you’ve already made the money.

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TraderScale rules read from the firm’s published help centre on 27 August 2026. Other firms’ rules vary considerably; verify with the specific firm before trading.