Rule Audit review: backtest your trading rules before you pay for a prop firm challenge

The short answer

Rule Audit is a focused, honest backtester for forex and gold traders who trade by rules. Its best decision is to default to the sceptical view: costs are on unless you take them off, a run without costs is flagged, results are labelled in-sample, and the verdict tells you when there are simply too few trades to judge. For a prop firm trader, that is the right order of questions: is there an edge after costs, on enough trades, before you pay to find out live?

• Good for: checking a rule-based forex or gold strategy before a challenge, comparing versions of your rules side by side, and catching strategies that only work with zero costs.
• Not for: discretionary trading, stocks, indices or crypto, automated live trading, or simulating a specific firm’s drawdown rules (you still check those yourself; we show how below).
• To try it: new accounts get 3 backtests free; an account is required.

Why prop firm challenges are lost

The odds are not in the average trader’s favour. In March 2025, Finance Magnates reported that The Funded Trader’s challenge pass rate ranged from 5 to 10%, and that only around 20% of those who passed received any payout. In the same piece, data from FPFX Tech, a technology provider to prop firms, put the share of 300,000 accounts that reached a payout at 7%. These are figures from the industry itself, measured in different ways, but they point the same way: most challenge fees are never earned back.

The reason is built into the rules. A challenge does not end when a strategy is wrong on average; it ends the first time the account touches a limit. A strategy with a small real edge can still fail a challenge if its normal losing streaks are deeper than the drawdown allows. And a strategy that looks fine on a chart can have no edge at all once spread, slippage and commission come out of every trade.

That leaves three things to know before you pay:

1. Is there an edge after costs? Not on a clean chart, on prices you would actually have paid.
2. Is it based on enough trades? Twenty good trades tell you very little. A strategy needs enough trades that luck is not the simplest explanation.
3. Do its normal bad runs fit inside the firm’s limits at the risk per trade you plan to use?

Rule Audit is built around the first two. The third is a short sum you do with its results, covered below.

What Rule Audit is (and what it is not)

Rule Audit is a web app, currently in beta, for testing rule-based strategies on historical data. Its homepage sums it up as “Audit your trading rules before you trade them.” Four ideas run through the product:

• Rules you can read. Every strategy is also written out in plain English, so you can check it says what you meant before you trust its results.
• Costs included. Spread, slippage and commission are on by default, and every report states which costs it used.
• An honest verdict. Each run ends with a verdict and the reasons for it, and the thresholds behind the verdict are shown, not hidden.
• Every run is a version. Each run saves the exact rules it used, so you can compare versions side by side.

What it is not: a signal service, a trading bot, a broker or a promise. It does not trade for you, and its terms describe it as a research and education tool that is not investment advice. It tests your ideas; it does not give you any.

How it works, step by step

1. Build. Assemble the strategy from 33 building blocks: prices, indicators, conditions, logic, entries and exits, stops and sizing. No code. If you can write your rules down as “when this and this, enter; exit when that”, you can build them.
2. Read. Rule Audit writes the strategy back to you in plain English. Read it carefully. A rule that says something slightly different from what you meant is the cheapest bug you will ever find.
3. Backtest. Run it on a major or cross forex pair, or gold (XAUUSD), on a timeframe from M1 to D1, with costs applied by default. How much history is available depends on the timeframe.
4. Verdict. Each run ends with one of four verdicts and the reasons for it.
5. Iterate. Change a rule and run it again. Each run keeps the exact rules it used, so you can see what the change did instead of trying to remember.

The plain-English step deserves more credit than it sounds. Most backtesting mistakes are not maths mistakes; they are rules that do not say what the trader thinks they say. A stop measured from the wrong price, a condition that checks the current candle instead of the closed one, an “and” that should be an “or”. Seeing the strategy in words is a fast way to catch those before they cost you a run, or a challenge.

The four verdicts and what to do with each

Every backtest ends in one of four verdicts: too few trades, no edge, fragile or promising. Rule Audit shows the thresholds behind them, so read the reasons, not just the label. Here is how we would act on each one if a challenge were on the line.

The most valuable verdict is often the disappointing one. “No edge” after three free backtests costs you nothing. Finding out the same thing halfway through a paid challenge costs the fee, and often a second one when you try again.

Why costs on by default matter

Costs are where many good-looking strategies quietly die. You pay the spread on every trade, slippage when the fill is worse than the price you saw, and commission on many prop firm and ECN accounts. None of that shows on a chart, and the more often a strategy trades, the bigger the share of its edge that goes to costs.

A made-up but typical example: a scalping strategy that averages 3 pips per trade before costs looks healthy. If spread, slippage and commission come to 1.5 pips a round trip, half of that edge is gone. At 2.5 pips, almost all of it is, and a small rise in spreads during news would push it negative. The same rules on a higher timeframe, with bigger targets, might shrug the same costs off.

Rule Audit treats costs as the default rather than an option you have to remember. Every report states which costs were applied, and a strategy tested without costs is flagged. That matters most for exactly the strategies prop firm traders are tempted by: frequent, small, intraday trades on gold and the major pairs.

Using Rule Audit before you buy a challenge

Here is a workflow that fits Rule Audit’s free tier and scales to a paid plan. Write your firm’s rules down first: the profit target, the daily loss limit, the maximum drawdown and whether it is static or trailing, and when the trading day resets. Firms word these differently, so read their own rules page, not a summary.

1. Write the strategy down as rules

Entry, exit, stop, size. If part of it is “I just know when it looks right”, that part cannot be backtested, and it is worth knowing that before the challenge rather than during it.

2. Build it and read it back

Build it from the blocks and read the plain-English version line by line. Fix anything that is not exactly what you trade.

3. Run it with realistic costs on the market you will trade

Use the pair or gold and the timeframe you will actually trade in the challenge. Keep costs on. If the verdict is “too few trades”, add history before you change anything else.

4. Check it somewhere you did not build it

Rule Audit labels its results in-sample: they describe the data the rules were tested on. If you tuned the rules on EURUSD, run the final version, unchanged, on a pair you never looked at while building it. An edge that only exists on the pair you tuned it on is a warning sign.

5. Do the drawdown sum

A backtest tells you whether the rules had an edge. The challenge asks a different question: will the normal bad runs fit inside the limits? Losing streaks are longer than most traders expect, even for a decent strategy. If trades are independent, these are the chances of at least one losing streak of a given length somewhere in 100 trades:

Now put your risk per trade next to it. Say a challenge has a 5% daily loss limit and a 10% maximum drawdown (common numbers, but use your firm’s). Risking 2% a trade, five losses in a row take about 10% off the account: the whole drawdown, from a streak that a 50% strategy has an 81% chance of hitting somewhere in 100 trades. Risking 1%, the same streak costs about 5%, and eight in a row about 8%. Risking 0.5%, even ten in a row costs about 5%.

The rule of thumb that falls out of this: size each trade so the longest losing streak you can reasonably expect, at your strategy’s win rate, fits inside the maximum drawdown with room to spare, and the losses you could take in one day fit inside the daily limit. A strategy with a real edge and the wrong size still fails the challenge.

6. Demo trade it before you pay

A promising, out-of-sample-checked result with a sensible size is a reason to trade it on a demo account for a few weeks, not to skip that step. A demo shows you what a backtest cannot: whether you actually follow the rules when you are in a losing streak.

What it leaves to you

A fair review says where a product stops. From what Rule Audit describes on its site as of October 2026:

• No prop firm rule simulation. The site does not mention modelling a specific firm’s daily loss limit, trailing drawdown or consistency rules. The streak sum above covers the basics; a firm’s exact rule wording still needs reading.
• Forex and gold only. Major and cross pairs and XAUUSD. Index and futures traders, and crypto traders, will need something else.
• In-sample results. Rule Audit is upfront that its results describe the data tested. Checking on data you did not build on is up to you.
• Swaps are not mentioned. The costs listed are spread, slippage and commission. If your strategy holds trades overnight or over weekends, allow for swap charges yourself.
• Rule-based only. If your edge is discretionary, a backtester can only test the parts you can write down.
• Beta, and data from third parties. The terms say the market data comes from third-party providers and can contain gaps or errors. Treat an extreme result as a reason to look closer.

None of these are hidden. The product is clear about what a backtest is and is not, which is more than most tools in this space manage.

Plans and pricing

Rule Audit prices by how many backtests you run a month:

Plans bill monthly or yearly. The homepage did not list prices when we wrote this, so check them on ruleaudit.com before you choose. Its refund policy says payments are generally non-refundable, with full refunds for billing mistakes such as a double charge or a charge after cancelling. Cancelling keeps the plan active until the end of the period you paid for.

The useful comparison is not with other software but with a challenge fee. If a month of backtests saves you one failed evaluation, it has paid for itself.

Who it is for, and who should skip it

Rule Audit fits you if:

• You trade forex or gold by rules you can write down, and you are about to pay for a prop firm challenge.
• You have failed a challenge and want to know whether it was the strategy, the size or the execution.
• You want an honest “no” more than a flattering equity curve.
• You do not code, or you do not want to write a backtest from scratch every time you have an idea.

Skip it, for now, if:

• You trade indices, futures, stocks or crypto.
• Your trading is discretionary and cannot be written as rules.
• You want a tool that trades for you, or tells you what to trade.

The pre-challenge checklist

Questions traders ask