Almost every prop firm allows expert advisors. Almost every prop firm has closed accounts for using one. Both statements are true because the permission comes with limits that are rarely spelled out on the sales page.
Automation is not the issue. Certain kinds of automation are. Understanding which is which decides whether your EA is an asset on a funded account or a refunded fee.
What is normally allowed
- Fully automated strategies that trade your own logic on your own account
- Semi-automated tools: signal alerts, trade managers, partial-close and trailing-stop utilities
- Strategy testers and backtesting tools run outside the live account
- Custom indicators that only visualise data
- EAs that manage risk: position sizing, break-even, time-based exits
A discretionary trader using a position-size calculator and a trade manager is using automation in the way firms expect. So is a fully systematic trader running one EA on one account.
What gets an account closed
| Prohibited behaviour | Why firms care | How it shows up |
|---|---|---|
| Latency arbitrage | Firm pays for a price feed, not a speed exploit | Sub-second entries clustered on feed updates |
| Tick scalping on stale quotes | Profit comes from the platform, not the market | Hundreds of tiny trades, near-zero hold time |
| Copying between accounts | Doubles exposure on one signal | Identical entries across accounts |
| Sharing or reselling an EA licence | One licence, many accounts | Same trade fingerprint on unlinked accounts |
| Martingale / grid with size escalation | Small edge hides tail risk | Lot size grows after losses |
| Exploiting demo or server glitches | Not a real market edge | Impossible fills reported by risk engine |
| High-frequency trades above a stated cap | Server load and abuse | Trade counts in the thousands per day |
Most of these are not about the EA itself. They are about where the profit comes from. If your bot makes money by being faster than the price feed, on a trade the market never really offered, you are the counterparty the firm did not agree to.
How firms detect automation
Detection is mostly statistical, and it does not require deep inspection of your machine. Risk systems look at:
- Time from price event to order submission, measured in milliseconds
- Hold time distribution. Human traders rarely close 90% of positions in under 20 seconds
- Correlation between your account and other accounts, by timestamp and instrument
- Consistency of lot size to four decimal places on every trade
- Trade count per day versus the account’s stated limits
- Entries that are impossible to fill at the displayed price
A strategy running on five-minute bars with a stop and a target looks nothing like latency arbitrage in this data. A bot chasing 2-pip moves on a 1-second chart looks exactly like it, whether or not that was your intent.
The permission you actually bought
Prop firm agreements differ by account type. Higher-tier and promotional accounts frequently restrict or forbid full automation, while standard evaluations allow it. Two things to confirm in writing before you attach an EA:
- Whether the specific account type permits fully automated trading, not just ‘EAs’
- Whether the EA must be registered with the firm before use. Some firms require an EA declaration form
Get the confirmation in a support ticket and keep it. If a payout is later refused with a vague reference to automated trading, the ticket is your evidence.
Running an EA without losing the payout
| Habit | Why it protects you |
|---|---|
| One EA, one account, one licence | Removes the copy-trading flag entirely |
| Trade your own logic, not a purchased signal EA | Fingerprint matches thousands of other users |
| Test drawdown under the firm’s rules, not generic ones | Trailing drawdown can fail an EA that passes a static test |
| Cap trades per day well below the firm limit | Stays clear of the HFT threshold |
| Avoid sub-minute timeframes on funded accounts | The single biggest automation red flag |
| Keep a human kill switch | Risk engine failures and news gaps are not in your backtest |
| Log every trade with server timestamp | Lets you prove behaviour if questioned |
The drawdown math that kills EAs
An EA that survives a 10% static drawdown can fail a 10% trailing drawdown on the same trades, because the trailing floor rises with every equity high. Backtests almost never model this. Before attaching any bot to a trailing-drawdown account, take its worst 30-day window and apply the firm’s trailing rule to the equity curve, then check whether the account would still be alive. The drawdown calculator does the arithmetic for both rule types.
Equally important: EAs produce their losses in clusters, because a regime change invalidates multiple setups at once. A 1%-per-trade risk with five simultaneous positions is a 5% risk event, and many firms cap simultaneous exposure for exactly this reason. Check the concurrent position limit before your bot opens its sixth trade.
What to do if you want to build one
The realistic path for most traders is a single-purpose EA: a rule set you can describe in one paragraph, tested on one instrument, with hard-coded risk caps. Bots that try to detect and trade every regime tend to produce the trade-count and hold-time patterns that get accounts closed, and they are hard to debug when a funded account is on the line.
If you are commissioning a build, specify the risk constraints as requirements, not afterthoughts: maximum lots, maximum concurrent positions, no size increase after a loss, a hard daily stop, and a news blackout window. Those five constraints are what separate a bot that survives a prop firm review from one that gets flagged.
We build and repair trading robots (MT4/MT5, MQL5) for a fixed price on Fiverr: view our MQL5 development services.
Our own expert advisor, VitalEdge Gold, is live on the MQL5 Market: fixed risk per trade, hard daily stop, no martingale. See the VitalEdge Gold EA on MQL5.
Written by Justice Manyika — trading systems builder, Johannesburg. Educational content only, not financial advice. See our disclaimer.
The firm whose rules these calculators are built around
Blueberry Funded’s drawdown type, daily loss limit and consistency wording are the reference numbers on this site. I read their rules line by line and wrote up every catch, including the parts I do not like, in the full review.
Check Blueberry Funded’s current terms or read the full review first
Disclosure: affiliate links on this page may earn me a commission if you sign up, at no extra cost to you. It does not affect the maths or the rules described above.