modbender Vynn Backtester
Backtest any trading strategy with natural language. Get Sharpe ratio, returns, drawdown, and full equity curves in seconds.
What it does
- Natural language strategies: Describe your strategy in plain English and Vynn translates it into a runnable backtest
- Structured strategies: Power users can pass precise entry/exit rules as JSON
- Full metrics: Sharpe ratio, total return, max drawdown, win rate, trade count, and equity curve
- Multi-ticker: Backtest across any combination of stocks, ETFs, or indices
- Strategy comparison: Compare multiple strategies head-to-head, ranked by Sharpe ratio
- No infrastructure: No local data downloads, no dependencies beyond Python stdlib
Setup
- Get a free API key at the-vynn.com (10 backtests/month, no credit card)
- Set
VYNN_API_KEYin your environment or skill config - Run
/backtest "your strategy here"from any OpenClaw agent
Quick start
# Sign up (instant, returns your API key)
curl -X POST https://the-vynn.com/v1/signup -H "Content-Type: application/json" -d '{"email": "you@example.com"}'
# Set the key
export VYNN_API_KEY="vynn_free_..."
Usage examples
Simple natural language backtest
/backtest "RSI mean reversion on AAPL, 2 year lookback"
Momentum strategy
/backtest "MACD crossover on SPY with 20/50 EMA filter"
Multi-ticker portfolio
/backtest --tickers AAPL,MSFT,GOOGL --strategy "momentum top 3"
Structured entry/exit rules
/backtest '{"entries": [{"indicator": "RSI", "op": "<", "value": 30}], "exits": [{"indicator": "RSI", "op": ">", "value": 70}]}' --tickers AAPL
Compare strategies
from plugin import VynnBacktesterPlugin
vynn = VynnBacktesterPlugin()
results = vynn.compare(
strategies=[
"RSI mean reversion",
"MACD crossover",
"Bollinger band breakout",
],
tickers=["SPY"],
)
for r in results:
print(f"{r.strategy}: Sharpe={r.sharpe_ratio}, Return={r.total_return_pct}%")
Environment Variables
| Variable | Required | Description | Default |
|---|---|---|---|
VYNN_API_KEY |
Yes | Your API key from the-vynn.com | -- |
VYNN_BASE_URL |
No | Override API base URL (for self-hosted instances) | https://the-vynn.com/v1 |
External Endpoints
| Endpoint | Purpose | Data Sent |
|---|---|---|
https://the-vynn.com/v1/backtest |
Execute a strategy backtest | Strategy text, ticker list, lookback period |
https://the-vynn.com/v1/signup |
Free API key registration | Email address |
Security & Privacy
- All requests authenticated via
X-API-Keyheader - Strategy descriptions and ticker lists are sent to the Vynn API for backtest execution
- No trading data, portfolio holdings, or personal information is stored beyond the backtest run
- Backtest results are ephemeral and not persisted on Vynn servers
- No credentials are stored by the skill -- only your API key in environment variables
- Source code is fully open: github.com/beee003/astrai-openclaw
Model Invocation
This skill does not invoke any LLM models. It sends strategy descriptions to the Vynn backtest engine, which is a quantitative execution engine (not an AI model). No prompts or completions are generated.
Pricing
- Free: 10 backtests/month, all features, no credit card required
- Pro ($29/mo): Unlimited backtests, priority execution, extended lookback periods