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Forex Scalping EA Overview

Jul 12, 2025

Overview

This lecture covers the step-by-step process of coding a Forex scalping trading robot (Expert Advisor) in MetaTrader 5 using MQL5, including strategy logic, backtesting, and detailed variable/function explanations.

Strategy Performance & Testing

  • EA (Expert Advisor) starts with $1,000 and can reach ~$41,800 over a year.
  • Achieves 92% win rate on both long and short trades; 11-17% relative drawdown.
  • No running drawdowns; best performance on USDJPY, GBPUSD, and EURUSD, 5-minute charts.
  • Performs well in trending markets; may stagnate or lose in ranging/volatile periods.
  • Requires tight spreads (<0.5 pips) and brokers that allow close trailing stops.

Strategy Logic

  • EA bets that when price breaks the last high or low, it will continue 1.5 pips further.
  • Entry orders placed at last high for buys, last low for sells, based on chosen criteria (e.g. highs/lows, moving average crossovers, RSI).
  • Trailing stop loss activates after 1.5 pips in profit, trailing by 1 pip.

MetaTrader 5 and Coding Setup

  • Download and install MetaTrader 5 for your OS from official site.
  • Use Market Watch to select currency pairs; Navigator to log in to broker account.
  • Strategy Tester is used for backtesting EAs.
  • Code EAs in MetaEditor using MQL5 language.

Key Variables & Inputs

  • User-defined inputs: risk percent per trade, chart timeframe, bars to analyze for highs/lows, TP/SL/trailing values, trading hours, magic number (EA identifier), order distances, expiry bars.
  • Use 'input' keyword for user-defined variables; provide clear descriptions for each input.

Key Functions Implemented

  • isNewBar: Checks if a new candle has opened to avoid repeating actions every tick.
  • findHigh / findLow: Identifies local highs/lows using user-defined bar range.
  • calculateLots: Calculates position size based on risk %, stop loss, account balance, and broker constraints.
  • executeBuy / executeSell: Places buy/sell stop orders at defined entry points with proper SL, TP, lot size, expiry.
  • closeAllOrders: Closes pending orders outside trading hours or after expiry.
  • trailStop: Aggressively trails stop loss once trade moves into profit; works on every tick.

EA Logic Flow

  • On EA initialization, sets magic number and loads user inputs.
  • On each new bar, checks trading hours and for existing orders/positions.
  • Finds new high/low and places stop orders if none exist.
  • During each tick, trails stop losses if position moves in profit.
  • Periodically closes pending orders if outside trading hours.

Testing & Final Advice

  • Code is visually tested and debugged using breakpoints and MetaTrader's visual mode.
  • EA is highly sensitive to market conditions and broker settings.
  • Recommended to forward-test in demo account for several months before live deployment.

Key Terms & Definitions

  • EA (Expert Advisor) — automated trading robot for MetaTrader.
  • MQL5 — programming language for MetaTrader 5 EAs.
  • Pip/Point — basic unit of price movement in Forex; 10 points = 1 pip.
  • Trailing Stop Loss — dynamic stop order that follows price movement.
  • Magic Number — unique identifier for EA’s trades.
  • Backtesting — running EA on historical data to evaluate performance.

Action Items / Next Steps

  • Download and install MetaTrader 5, set up broker account, and access Market Watch and Strategy Tester.
  • Code the EA as taught, inputting required variables and functions step by step.
  • Test the EA in a demo account for several months to observe performance.
  • Watch next lecture for modifications to support Gold, Bitcoin, and US indices trading.

Full transcript