AI-powered strategy backtesting

Backtest any trading idea in plain English.

Describe your strategy in a sentence. Stratfy parses it with AI, simulates it against real historical market data, and stress-tests it across 1,000 Monte Carlo scenarios — all in your browser.

See how it works
No credit card · Free forever with your own AI key
What Stratfy is

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 real historical daily price data for US equities, ETFs and Brazilian B3 tickers, with commissions and slippage 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. The free tier is unlimited when you supply your own Claude, OpenAI or Gemini API key; paid tiers include hosted AI so you never handle an API key at all.

See it live

Backtest your strategy against real market data.

app.stratfy.io/backtest
stratfy
Backtest Monte CarloOptionsCompare
∞ BYO key
Total Return
+148.2%
Sharpe
1.84
Max DD
−12.4%
CAGR
+13.9%
Equity Curve — real historical data
LIVE
Keep scrolling to unlock live trading ↓
Monte Carlo · 1,000 paths
5th pctile+38.2%
Median+112%
95th pctile+247%
Risk of ruin0.4%
Win rate
Hit rate61.4%
Avg win2.1R
Profit factor1.94
Trades214
Strategy parsed by AI
The pipeline

How AI strategy backtesting works.

You type

Buy when the 9-day moving average crosses above the 21-day one and the 14-period RSI is above 50. Add to the position on pullbacks to the 9-day average, but only while the trend is up. Exit when RSI pushes past 70, and always cap the loss with a 2% stop while taking profit at 4%.

AI parses

Rules out

entry: EMA(9) × EMA(21)
filter: RSI(14) > 50
stop 2% · target 4%
exit: RSI ≥ 70
The lab

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 real historical prices with commissions and slippage — not synthetic curves.

Monte Carlo

1,000 reshuffled futures. Ruin probability, confidence bands and drawdown distributions.

Options Lab

Black-Scholes pricing, Greeks and rolling expiration backtests for multi-leg structures.

Compare Strategies

Run saved strategies side by side over the same window, capital and cost assumptions.

Python Export

Broker-ready script for Interactive Brokers, Alpaca or any broker with a Python API.

Specifications

Capabilities at a glance.

Stratfy technical specification
CategoryTrading strategy backtesting software
PlatformBrowser-based. No install, no local Python environment.
Strategy inputPlain English sentence, parsed into rules by AI. No coding required.
Markets coveredUS equities and ETFs, major international tickers, and Brazilian B3 equities, FIIs and BDRs (.SA suffix)
IndicatorsSMA, EMA, RSI, MACD, Bollinger Bands, ADX, ATR, Stochastic, OBV, VWAP
Risk-free rateUS T-bill for USD strategies; CDI / Selic for BRL strategies
Monte Carlo1,000 resampled paths per run, with ruin probability, percentile bands and drawdown distribution
Portfolio modeMulti-ticker basket, up to 20 tickers per strategy on paid tiers
OptionsBlack-Scholes pricing, full Greeks, multi-leg structures, rolling expirations
Costs modelledCommission in basis points per side, plus realistic slippage
Export formatsPython script (Interactive Brokers, Alpaca), CSV trade log, PNG charts
LanguagesEnglish and Brazilian Portuguese
PricingFree with your own AI API key; Pro $19/month; Elite $49/month. BRL billing via Pix and boleto.
Pricing

Backtesting software that starts free.

Free forever with your own AI key. Credits only apply when we host the AI for you.

Free

$0forever
Your own AI key · no credits
  • Unlimited backtests & Monte Carlo
  • Bring your own Claude / GPT / Gemini key
  • No credits, no card — ever
  • Strategy library & Python export
Most popular

Pro

$19/mo
500 AI credits / month
  • No API key needed — we host the AI
  • Options Lab & strategy compare
  • Priority parsing queue
  • Email support

Elite

$49/mo
2,000 AI credits / month
  • Everything in Pro
  • Credit rollover up to 2×
  • Early access to new features
  • Priority support
Free versus paid, feature by feature
Free (BYO key) Paid (credits, no key)
AI strategy analysisYes — but you paste your own key + pay Anthropic yourselfWe handle the key. Nothing to set up, one bill
Backtest engineFullFull
Saved strategies3 max, this-browser-only (localStorage)Unlimited, synced to your account across devices
Price history depth~2 yearsFull history (10+ yrs)
Tickers per strategyUp to 3Up to 20
Portfolio mode / Compare tabLocked (preview only)Unlocked
Monte CarloShort runFull iterations
Chart / Python exportWatermarked "Powered by Stratfy"Clean, unwatermarked
Support / speedCommunityPriority
1 hosted AI analysis = 10 credits · Pix & boleto accepted for BRL
FAQ

Questions, answered.

Do I need to know how to code?

No. You write your strategy as an ordinary sentence and the AI turns it into rules. Stratfy is built specifically for traders who do not write code. If you do code, you can still export the finished strategy as a Python script.

Is there a free version?

Yes. Bring your own Claude, OpenAI or Gemini API key and the entire engine is free forever — unlimited backtests and Monte Carlo runs, no credits and no credit card. You only pay if you want Stratfy to host the AI for you.

What are credits, then?

Credits only apply on hosted plans, where Stratfy runs the AI so you never touch an API key. One hosted strategy analysis costs 10 credits. Backtests, Monte Carlo runs and charts are always free and never consume credits.

Does it support Brazilian stocks, B3 and FIIs?

Yes. Stratfy supports B3 equities, FIIs and BDRs using the .SA ticker suffix — for example PETR4.SA, VALE3.SA or HGLG11.SA. Brazilian strategies are benchmarked against IBOV and use CDI or Selic as the risk-free rate rather than US T-bills. Billing is available in BRL via Pix and boleto.

What data does it use?

Real historical daily OHLCV prices for US equities, ETFs, major international tickers and Brazilian B3 tickers. Every simulation applies commission in basis points per side plus realistic slippage, so the equity curve reflects trading costs rather than an idealised fill.

Is backtesting accurate?

A backtest is an estimate, not a promise. Stratfy improves on naive backtests by charging commission and slippage on every fill and by running 1,000 Monte Carlo resamples that reshuffle the order of wins and losses — which exposes how much of a result came from luck. It cannot eliminate overfitting: a strategy tuned until it looks perfect on past data usually disappoints in future data.

How is this different from TradingView, QuantConnect or Composer?

TradingView needs Pine Script and QuantConnect needs Python or C#; both assume you can code. Composer uses a visual block editor and is limited to US symphonies. Stratfy takes an ordinary English sentence as the input, covers Brazilian B3 tickers alongside US markets, runs entirely in the browser, and is free without limits if you supply your own AI key.

Can I cancel anytime?

Yes. Cancel in one click from your account page. Remaining credits stay usable until the end of your billing cycle, and you can keep using the free tier with your own API key afterwards.

Is this financial advice?

No. Stratfy is simulation software, not an advisor or a broker. Results are hypothetical and past performance never guarantees future results. Nothing on this page is a recommendation to buy or sell any security.