Standard backtesting engines assume tight, fixed spreads. Trade exotic pairs like USD/ZAR or USD/TRY, and that assumption will ruin your res

Standard backtesting engines assume tight, fixed spreads. Trade exotic pairs like USD/ZAR or USD/TRY, and that assumption will ruin your results. At INTERMEDIATE level, you need a backtester that models variable spreads, slippage, and rollover costs specific to exotic pairs. Let's build one. Core components of an exotic-aware backtester: Variable spread model: Read historical spread data or approximate using session-based spread tables (e.g., 20 pips during NY for USD/MXN, 60 pips during Asian hours). Apply the spread at entry and exit, not just a flat 15-pip assumption. Slippage simulation: Exotics can slip 5-10 pips on market orders during liquid windows...