Grail Sail helps you turn a hunch about the market into a clear set of rules, then shows you what would have happened if you'd followed them — using real historical data. No trading experience required, and nothing costs you money until you decide it's worth paying for. Build your strategy, and your confidence, at the same time.
No credit card. No experience needed. Nothing happens to real money unless you choose to act on what you learn.
Here's an example: "Buy when a stock has dropped a lot and looks like it's due to bounce back." Below is how that idea looks once it's turned into rules.
0–100
Simple moving average
RSI_14 < 30 AND SMA20 > SMA500–100
RSI_14 > 70 · SL 5% · TP 15%Drag conditions onto the canvas — things like "price has dropped a lot" or "this is trending up" — and combine them with simple AND/OR logic. Each one comes with a plain-language explanation, so you're never guessing what it means.
Run your idea against years of real market data, completely free. This isn't a prediction — it's a way to learn how your idea behaves in different conditions.
If you like what you see, you can get a daily list of stocks that match your rules today. You decide what to do with it — nothing is automatic.
The same tools professional traders rely on, explained in plain English so you don’t need a finance degree to use them.
Test across the full S&P 500 and Russell 1000 universe. Daily OHLCV data updated every market close.
Combine conditions with AND/OR logic across multiple rule groups. Compare indicators against values or against each other.
Set stop loss, take profit, and maximum holding days directly in the strategy builder.
Results are split across 5 distinct time periods to give you a more realistic picture — not just one lucky stretch of data.
Historical tests across hundreds of tickers complete in around a minute, not hours. Built on a vectorised Python engine.
Historical testing is free forever — practice and learn with zero risk. Upgrade only if you want daily signals.
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