What is Expert Advisor (EA)?
An automated trading program for MetaTrader 4/5 that executes trades based on pre-programmed rules.
An Expert Advisor (EA) is an automated trading program written in MQL4 (MT4) or MQL5 (MT5) that executes trades automatically based on coded rules. EAs can run 24/5 without supervision, react to market conditions in milliseconds, and avoid emotional decision-making.
EAs come in two flavors. Trend-following EAs catch directional moves using moving averages, breakouts, or momentum indicators — they perform well in trending markets and lose in chop. Mean-reversion EAs trade reversals using overbought/oversold signals or grid patterns — they perform well in ranging markets and can blow up in trends.
EA execution requires a broker that allows automated trading (most do — explicitly check Terms of Service), low latency (a VPS near the broker's server is standard for serious EAs), and adequate spreads (a 10-pip spread destroys EAs designed for 5-pip targets). Backtesting alone is insufficient — forward-test on a demo or small live account before scaling capital.