Expert Advisor (EA)
An Expert Advisor is a piece of software written in MQL (MQL4 for MetaTrader 4, MQL5 for MetaTrader 5) that attaches to a chart and trades on your behalf. It reads price data, applies the rules its author programmed, and sends orders to your broker without you clicking anything.
An EA is only as good as its rules. It does not think, adapt beyond what it was programmed to do, or know anything about the market that isn't in its code. When someone sells an EA, they are selling a fixed set of decisions packaged as software.
Covered in depth in Lesson 01: What an Expert Advisor actually is — and what it isn't.
Related terms
- MQL5 — The programming language used to write Expert Advisors and indicators for MetaTrader 5.
- Backtest — Running a strategy against historical price data to see how its rules would have behaved in the past.
- Slippage — The difference between the price an order requested and the price it actually filled at.
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