Playbook

Prop Firm EA Architecture

Design EAs that respect firm rules, protect your account, and give you the best chance to pass challenges and stay funded.

15 min read

Advanced

Firm Requirements EA Architecture Compliance Checklist

Understanding Prop Firm Requirements

Daily Loss Limit

Typical: 5% of starting balance

Maximum loss allowed in a single trading day. Breach = instant fail.

Implementation: Track daily P&L, halt trading when approaching 4% loss.

Max Drawdown

Typical: 10% of starting balance

Total drawdown from highest equity point. Trailing or fixed depending on firm.

Implementation: Monitor equity continuously, reduce position sizing as drawdown increases.

Profit Target

Typical: 8-10% for challenges

Required profit to pass challenge phase. Not usually relevant for funded phase.

Implementation: Focus on consistency rather than aggressive targets.

Trading Hours

Typical: Varies by firm

Some firms restrict weekend holding, news trading, or late Friday positions.

Implementation: Implement time filters to close positions before restricted periods.

Prohibited Strategies

Typical: Martingale, grid, HFT

Many firms ban scaling strategies, copy trading, and high-frequency approaches.

Implementation: Use fixed lot sizing, single entry per signal, reasonable trade frequency.

EA Architecture Components

Equity Guardian

Monitors account equity in real-time and enforces drawdown limits

// Check before every trade
if (AccountEquity() < StartEquity * 0.91) {
  // Within 1% of max drawdown - HALT
  CloseAllPositions();
  DisableTrading();
}

Daily Loss Tracker

Resets at midnight broker time, tracks cumulative daily P&L

// Track daily starting equity
if (IsNewDay()) {
  DailyStartEquity = AccountEquity();
}
DailyPnL = AccountEquity() - DailyStartEquity;
if (DailyPnL < -DailyLossLimit) {
  HaltUntilNextDay();
}

Position Sizer

Calculates lot size based on remaining risk budget

// Dynamic position sizing
RemainingRisk = MaxDailyLoss - CurrentDailyLoss;
MaxLotSize = RemainingRisk / (StopLossPips * PipValue);
ActualLotSize = MathMin(MaxLotSize, DefaultLotSize);

Time Filter

Prevents trading during restricted hours

// Friday closure example
if (DayOfWeek() == 5 && Hour() >= 20) {
  CloseAllPositions();
  return; // No new trades
}

Prop Firm Compliance Checklist

Before deploying your EA on a prop firm account, verify all these items. Critical items are absolute requirements — missing any can result in instant failure.

Hard stop at 90% of max drawdown (with buffer)Critical

Daily loss tracking with automatic haltCritical

No martingale or grid scaling logicCritical

Fixed lot sizing or conservative dynamic sizingCritical

Time filters for firm-specific restrictionsCritical

Position closure before weekends (if required)

News filter to avoid high-impact events

Maximum concurrent positions limit

Logging for trade review and compliance

Emergency close-all button/function

Common Prop Firm Mistakes

Cutting it too close to drawdown limits

Why it matters: Slippage, gaps, and spread widening can push you over. A 9.8% drawdown can become 10.5% in seconds.

Fix: Set internal limits 1-2% tighter than firm limits. Halt at 8% if firm allows 10%.

Not accounting for overnight/weekend gaps

Why it matters: Holding through weekends means gap risk that can blow through stop losses.

Fix: Implement Friday closure or significantly reduce position size before close.

Using the same EA settings across different firms

Why it matters: Each firm has different rules. What passes FTMO might fail MFF.

Fix: Create firm-specific presets. Document each firm's exact requirements.

Aggressive trading to hit profit targets quickly

Why it matters: Rushing leads to overtrading, larger positions, and blown accounts.

Fix: Aim for 1-2% weekly. Slow and steady beats fast and failed.

No testing on prop firm demo/trial

Why it matters: Your regular demo won't have the same rules enforcement.

Fix: Most firms offer free trials or cheap retries. Test your EA there first.

Templates & Presets

FTMO-Compatible Settings

Pre-configured for 5% daily / 10% max drawdown with Friday closure.

MFF-Compatible Settings

Optimized for My Forex Funds rules with trailing drawdown protection.

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