Most traders blow prop firm evaluations for two reasons: they trade an edge that was never real, or they size correctly for profit but not for the trailing drawdown. Both are solvable before you ever wire an evaluation fee — if you treat the eval as a quant problem instead of a gamble.
1. Prove the edge is real first
A strategy that won once out of a hundred variations isn't an edge — it's luck in a costume. Before you take it near a funded account, it should survive an untouched holdout, a Monte-Carlo reshuffle, and an overfitting check (deflated Sharpe, PBO). If it dies in simulation, it was going to die on your evaluation too — you just saved the fee.
2. Simulate the firm's actual rules
Every firm — Topstep, Apex, FundedNext and the rest — has its own profit target, daily-loss limit, trailing/EOD drawdown, and consistency rules. The right question isn't "is my strategy good?" but "what are my pass odds under this firm's exact rules?" A prop-firm simulator runs your strategy through each rulebook and returns pass probability, how often you'd brush the trailing drawdown, daily-loss odds, and median days to pass.
3. Size for the drawdown, not the target
The trailing drawdown is what fails funded accounts, not the profit target. Position sizing that maximises expectancy will happily ruin you the first time a normal losing streak hits the trailing line. Model the ruin path explicitly and size so a routine drawdown doesn't end the account.
4. Survive after funding
Passing is half the job. The consistency cap and the trailing drawdown keep applying after you're funded, so "share of accounts still alive at day 60" matters more than a hero month.
TapeScript runs a 10-firm prop-firm simulator on every strategy — pass odds, trailing-drawdown near-misses, consistency-cap checks, time-to-payout, and post-funding survival — so you buy the evaluation you're actually likely to pass. See how it works →