I should say up front what I'm building, since it's the reason this sub exists and you'll all work it out anyway.

**Prop Desk** is a day trading simulator. You replay a real recorded market session candle by candle, watch each bar form, and trade it by hand at your cursor — without knowing what the next candle does. Five timeframes from daily to one-minute, seven indicators, speeds from 0.1× to 4×, fully offline. First build is **September 11**.

That's the product. Here's the part I actually care about, and the reason I think it belongs in a sub about methodology rather than a sub about trading.

**The premise: a simulator that flatters you is worse than no simulator.**

If practice is even slightly generous, it doesn't just fail to teach — it hands you confidence you haven't earned, and you carry that to a live account. That's the most expensive thing a practice tool can do to someone.

So the engine runs on rules it isn't allowed to break:

* **Scrolling can never improve a fill.** Viewport and execution are separate systems that don't share state.
* **Cash is derived from actual fills.** It can't drift and there's no path that nudges it.
* **Nothing renders before the bar that confirms it.** Auto-detected zones can't draw a bar early, so the chart can't foreshadow.
* **Execution never trusts the view layer.** Fills clamp to the replay index regardless of what's drawn.
* **A rejected rule never shows its good week in green.**

I didn't arrive at that list by being careful. I arrived at it by shipping the opposite — a missing timeframe case let the forming candle aggregate the whole day's sub-bars, so fills were being priced against a candle that contained the session high and low. Future prices, in execution, silently. I'll write that one up properly as its own post.

**The strategy lab is the part I'd most like torn apart.**

It ships with backtested rules, and it shows you the ones that **failed** alongside the one that didn't. Current numbers: **46 candidates tested, 1 survivor.** Significance corrected across 180 experiments rather than a single run. Holdout sealed and never touched. If a rule doesn't beat a no-mechanism drift baseline, it's labelled rejected and stays rejected everywhere in the UI — with the full argument for why the idea *should* have worked, and the specific weakness that sinks it.

I've not seen another retail trading product do that, and I'd genuinely like to know whether anyone here thinks showing failures is actively harmful rather than useful.

**Where it is:** built and playable, not finished. Still to come before launch — a session coach that puts your trades next to what a graded rule would have done, a harder session pack so the practice isn't biased toward setups that worked, and the tutorial.

**If you want it on day one:** [propdesktrading.netlify.app](http://propdesktrading.netlify.app) — one email, September 11, nothing else.

And if you'd rather just argue with the methodology than sign up for anything, that's genuinely more useful to me. Tell me where the five rules above are insufficient.

*Simulation for practice. Not financial advice, not connected to any broker, no real money involved.*

I'm building Prop Desk — a day trading simulator that's engineered to never flatter you