Backtrader Slippage: Modeling Latency for HFT
What happens when your backtest shows a 20% annual return, but your live trading account bleeds out in a week? The culprit is often a flawed backtrader ...
What happens when your backtest shows a 20% annual return, but your live trading account bleeds out in a week? The culprit is often a flawed backtrader slippage model that ignores the reality of execution latency. In high-frequency trading (HFT), the difference between profit and loss is measured in milliseconds. A backtest that assumes instant execution at the closing price of a bar is not a simulation; it is a fantasy. To build a strategy that survives in live markets, you must model the friction of the real world: network delays, order book depth, and the time it takes for a signal to become a filled trade. Key fact: According to HftBacktest documentation, accurate backtesting requires accounting for both feed latency and order latency to simulate realistic market replay conditions. Standard backtesting often relies on a simple, fixed percentage to represent slippage. While this works for swing trading where execution happens over hours or days, it is catastrophic for HFT. In fast markets, slippage is not a static number; it is a dynamic function of liquidity, order size, and the precise moment your order hits the exchange.