Prop firms (FTMO, FundedNext, The5ers and others) promise you capital to manage if you pass their challenge. Many traders take their shot with an Expert Advisor. The problem: prop firm rules kill most robots — especially the ones that look most profitable on paper. Here is why, and how to check your EA before paying for a challenge.

The 3 rules that make robots fail

1. The daily loss limit. Most prop firms impose a maximum loss per day (often 5%). A robot that averages down or holds on to losing positions can breach that threshold in a single bad session — challenge over, even if the robot would have recovered afterwards.

2. The overall maximum drawdown. Often 10%. An EA with a historical drawdown of 15-20% is mathematically incompatible with a 10% challenge.

3. News and weekends. Many prop firms forbid (or penalise) trading during major announcements and holding positions over the weekend. A robot that ignores the economic calendar walks straight into the trap.

Why "profitable" robots so often fail

The irony: the most appealing EAs — martingale, grid, high-frequency scalping — are the worst candidates for a challenge. They produce smooth curves… then a drawdown spike that blows through the daily limit. A prop firm judges your worst day, not your average.

How to audit your EA before attempting a challenge

Before spending €100-500 on challenge fees, check four things:

  1. Intraday drawdown: has your EA ever gone below −5% within a single day? If so, it will fail sooner or later.
  2. Maximum drawdown: is it below the prop firm's limit (often 10%), with room to spare?
  3. Martingale / position sizing: does it increase size after a loss? → risk of a sudden breach.
  4. Behaviour around news: does it trade during high-impact announcements?

Check compatibility in a few minutes

Judgebot analyses your MT4/MT5 statement, calculates the real drawdown (intraday included), detects martingale behaviour, and a challenge simulator estimates your probability of passing a prop firm evaluation with that robot — the diagnostic is free.

👉 Scan your EA for free before paying for a challenge.

In summary

  • The daily loss limit and the maximum drawdown are the two challenge killers.
  • Martingale, grid and oversized positions are incompatible with a prop firm.
  • Audit your EA's real intraday drawdown before you pay — not after you fail.