Backtrader Backtrader is a Python event-driven backtesting framework that processes data bar-by-bar, simulating realistic execution with a built-in broker, order management, and position tracking. Unlike vectorized frameworks (vectorbt, pandas), backtrader walks through history one bar at a time, firing callbacks that let you implement complex order logic that depends on previous fills, partial executions, and conditional brackets. Event-Driven vs Vectorized | Aspect | Backtrader (event-driven) | vectorbt (vectorized) | |---|---|---| | Execution model | Bar-by-bar callbacks | Whole-array oper…