# Backtesting Trading Strategies
## Overview
Validate trading strategies against historical data before risking real capital. This skill provides a complete backtesting framework with 8 built-in strategies, comprehensive performance metrics, and parameter optimization.
**Key Features:**
- 8 pre-built trading strategies (SMA, EMA, RSI, MACD, Bollinger, Breakout, Mean Reversion, Momentum)
- Full performance metrics (Sharpe, Sortino, Calmar, VaR, max drawdown)
- Parameter grid search optimization
- Equity curve visualization
- Trade-by-trade analysis
## Prerequisites
Install required dependencies:
```bash
pip install pandas numpy yfinance matplotlib
```
Optional for advanced features:
```bash
pip install ta-lib scipy scikit-learn
```
## Instructions
### Step 1: Fetch Historical Data
```bash
python {baseDir}/scripts/fetch_data.py --symbol BTC-USD --period 2y --interval 1d
```
Data is cached to `{baseDir}/data/{symbol}_{interval}.csv` for reuse.
### Step 2: Run Backtest
Basic backtest with default parameters:
```bash
python {baseDir}/scripts/backtest.py --strategy sma_crossover --symbol BTC-USD --period 1y
```
Advanced backtest with custom parameters:
```bash
# Example: backtest with specific date range
python {baseDir}/scripts/backtest.py \
--strategy rsi_reversal \
--symbol ETH-USD \
--period 1y \
--capital 10000 \
--params '{"period": 14, "overbought": 70, "oversold": 30}'
```
### Step 3: Analyze Results
Results are saved to `{baseDir}/reports/` including:
- `*_summary.txt` - Performance metrics
- `*_trades.csv` - Trade log
- `*_equity.csv` - Equity curve data
- `*_chart.png` - Visual equity curve
### Step 4: Optimize Parameters
Find optimal parameters via grid search:
```bash
python {baseDir}/scripts/optimize.py \
--strategy sma_crossover \
--symbol BTC-USD \
--period 1y \
--param-grid '{"fast_period": [10, 20, 30], "slow_period": [50, 100, 200]}'
```
## Output
### Performance Metrics
| Metric | Description |
|--------|-------------|
| Total Return | Overall percentage gain/loss |
| CAGR | Compound annual growth rate |
| Sharpe Ratio | Risk-adjusted return (target: >1.5) |
| Sortino Ratio | Downside risk-adjusted return |
| Calmar Ratio | Return divided by max drawdown |
### Risk Metrics
| Metric | Description |
|--------|-------------|
| Max Drawdown | Largest peak-to-trough decline |
| VaR (95%) | Value at Risk at 95% confidence |
| CVaR (95%) | Expected loss beyond VaR |
| Volatility | Annualized standard deviation |
### Trade Statistics
| Metric | Description |
|--------|-------------|
| Total Trades | Number of round-trip trades |
| Win Rate | Percentage of profitable trades |
| Profit Factor | Gross profit divided by gross loss |
| Expectancy | Expected value per trade |
### Example Output
```
================================================================================
BACKTEST RESULTS: SMA CROSSOVER
BTC-USD | [start_date] to [end_date]
================================================================================
PERFORMANCE | RISK
Total Return: +47.32% | Max Drawdown: -18.45%
CAGR: +47.32% | VaR (95%): -2.34%
Sharpe Ratio: 1.87 | Volatility: 42.1%
Sortino Ratio: 2.41 | Ulcer Index: 8.2
--------------------------------------------------------------------------------
TRADE STATISTICS
Total Trades: 24 | Profit Factor: 2.34
Win Rate: 58.3% | Expectancy: $197.17
Avg Win: $892.45 | Max Consec. Losses: 3
================================================================================
```
## Supported Strategies
| Strategy | Description | Key Parameters |
|----------|-------------|----------------|
| `sma_crossover` | Simple moving average crossover | `fast_period`, `slow_period` |
| `ema_crossover` | Exponential MA crossover | `fast_period`, `slow_period` |
| `rsi_reversal` | RSI overbought/oversold | `period`, `overbought`, `oversold` |
| `macd` | MACD signal line crossover | `fast`, `slow`, `signal` |
| `bollinger_bands` | Mean reversion on bands | `period`, `std_dev` |
| `breakout` | Price breakout from range | `lookback`, `threshold` |
| `mean_reversion` | Return to moving average | `period`, `z_threshold` |
| `momentum` | Rate of change momentum | `period`, `threshold` |
## Configuration
Create `{baseDir}/config/settings.yaml`:
```yaml
data:
provider: yfinance
cache_dir: ./data
backtest:
default_capital: 10000
commission: 0.001 # 0.1% per trade
slippage: 0.0005 # 0.05% slippage
risk:
max_position_size: 0.95
stop_loss: null # Optional fixed stop loss
take_profit: null # Optional fixed take profit
```
## Error Handling
See `{baseDir}/references/errors.md` for common issues and solutions.
## Examples
See `{baseDir}/references/examples.md` for detailed usage examples including:
- Multi-asset comparison
- Walk-forward analysis
- Parameter optimization workflows
## Files
| File | Purpose |
|------|---------|
| `scripts/backtest.py` | Main backtesting engine |
| `scripts/fetch_data.py` | Historical data fetcher |
| `scripts/strategies.py` | Strategy definitions |
| `scripts/metrics.py` | Performance calculations |
| `scripts/optimize.py` | Parameter optimization |
## Resources
- [yfinance](https://github.com/ranaroussi/yfinance) - Yahoo Finance data
- [TA-Lib](https://ta-lib.org/) - Technical analysis library
- [QuantStats](https://github.com/ranaroussi/quantstats) - Portfolio analytics