Running an EA in a prop firm challenge

Plenty of challenges fail while the account is still in profit. Not because the trading was bad, but because a rule was broken that the trader never read. Automation makes this worse: a bot follows its instructions perfectly, including the ones that violate the agreement.

1. Is the EA allowed at all?

Some firms permit expert advisors freely, some ban them, and many sit in between: your own bot is fine, a commercially sold one is not, and a bot that many funded traders run simultaneously counts as prohibited copy trading. Get this answer in writing from support before you pay the fee.

2. How is the daily loss limit measured?

This clause ends more challenges than any other. Some firms measure from the previous day's closing balance, others from peak equity, and the difference is enormous for a strategy holding open positions overnight. Floating losses usually count. A grid sitting in a 4% unrealised drawdown can breach a 5% daily limit without closing a single trade.

Set the bot's own daily stop below the firm's limit, and have it halt rather than hope.

3. What happens at the weekend and around news?

• Some firms require all positions closed before Friday's close
• Many prohibit opening trades within a window either side of high-impact releases
• Others restrict holding through a rollover on certain instruments

Each of these needs to be a filter inside the EA. Remembering to do it manually works until the one Friday you are away from the screen.

4. Minimum trading days and consistency rules

A bot that hits the profit target in three days can fail a challenge requiring ten trading days. A newer and stricter rule caps how much of your total profit may come from a single day — clear the target in one lucky session and the payout is denied. Configure the bot to trade at a steady pace rather than sprinting.

5. Lot size limits and scaling

Firms usually cap the maximum lot size and total open volume. An EA that sizes as a percentage of balance can exceed that cap on a larger account without warning. Set a hard maximum in the inputs, below the firm's limit, and test that the bot respects it.

A realistic view

The challenge is a risk-management exam wearing the costume of a profit target. The most reliable approach is dull: small size, the same routine every day, a daily stop that triggers well before the firm's, and no attempt to finish early. Passing slowly still pays.