Backtest any trading idea in plain English.
Describe your strategy in a sentence. Stratfy parses it with AI, simulates it against a price file you bring, and stress-tests it across 1,000 Monte Carlo scenarios — all in your browser, with your data never leaving it.
Trading strategy backtesting software that runs in your browser.
Stratfy is a browser-based trading strategy backtester. You describe a strategy in plain English — for example, "buy the 9/21 EMA cross when RSI is above 50, exit at RSI 70 with a 2% stop" — and an AI model converts that sentence into explicit entry, exit, stop-loss and filter rules. Those rules are then simulated against daily OHLCV price data you supply as a CSV for US equities, ETFs or Brazilian B3 tickers, with per-side commission and a modelled slippage assumption applied, and stress-tested across 1,000 Monte Carlo resamples.
It is built for discretionary and systematic traders who want to validate an idea without writing code. There is nothing to install and no spreadsheet to maintain. You paste your own Claude, OpenAI or Gemini API key, so usage is unlimited and your provider bills you directly at cost.
Backtest your strategy against real market data.
The figures and chart below are illustrative, not the result of a real backtest.
How AI strategy backtesting works.
AI parses
Rules out
Everything you need to test a trading strategy.
AI Strategy Parse
Plain English in, precise rules out. Entries, exits, stops and filters extracted automatically by AI.
Real-Data Backtests
Simulated on the prices you load, with per-side commission and a modelled slippage assumption — not synthetic curves. Order size is not modelled, so costs are a floor; the Options Lab additionally models an assumed bid-ask spread.
Monte Carlo
1,000 futures resampled from your trades with replacement. Ruin probability, confidence bands and drawdown distributions.
Options Lab
Payoff diagrams and Greeks for multi-leg structures, priced with Black-Scholes. The historical backtest sits behind them as a secondary, assumption-heavy view.
Compare Strategies
Run saved strategies side by side over the same date range and starting capital. Each keeps its own commission setting.
Python Export
A readable Python translation of your strategy rules, to inspect and build on. Not a trading bot: it places no orders.
Capabilities at a glance.
| Category | Trading strategy backtesting software |
|---|---|
| Platform | Browser-based. No install, no local Python environment. |
| Strategy input | Plain English sentence, parsed into rules by AI. No coding required. |
| Markets covered | US equities and ETFs, major international tickers, and Brazilian B3 equities, FIIs and BDRs (.SA suffix) |
| Indicators | SMA, EMA, RSI, MACD, Bollinger Bands, ATR, Stochastic, VWAP |
| Risk-free rate | US T-bill for USD strategies; CDI / Selic for BRL strategies |
| Monte Carlo | 1,000 resampled paths per run, with ruin probability, percentile bands and drawdown distribution |
| Portfolio mode | Multi-ticker basket, up to 20 tickers per strategy |
| Options | Black-Scholes pricing, full Greeks, multi-leg structures, rolling expirations. European pricing applied to American contracts, one flat volatility across strikes, realized volatility as an IV proxy, dividends as a trailing continuous yield, and a modelled bid-ask spread: the payoff and Greeks are exact for the structure you define, the historical P&L is an approximation |
| Costs modelled | Equity: commission in basis points per side, plus a modelled slippage of bps + a fraction of ATR per side — grounded in shape, a stated assumption in size, and blind to order size, so it is a floor. Options: commission plus a modelled bid-ask spread that widens out of the money — also a stated assumption, not quoted data |
| Export formats | Python translation of the strategy rules (not a trading bot), CSV trade log, strategy library JSON |
| Languages | English and Brazilian Portuguese |
| Price | Free. No account, no credits, no subscription — you supply your own Claude, OpenAI or Gemini API key and pay that provider directly. |