An Expert Advisor (EA) is a program that trades automatically on MetaTrader (written in MQL4/MQL5). cTrader has cBots; TradingView uses Pine Script.
1Ideaclear rules
2CodeMQL5 / Pine
3Backtestyears of data
4Forward testdemo 1–3 months
5Go smallthen scale
The good
- No emotions, perfect consistency, works 24 hours.
- Years of data can be tested in minutes.
The risks
- Curve fitting: perfect backtest, terrible live results.
- Martingale and grid systems: they double down on losers and look amazing until one trend wipes the account.
- Execution differences between brokers.
- Tech failures: many traders run EAs on a VPS.
Judging an EA
| Check | Good sign |
|---|---|
| Track record | Verified live results, not just backtests |
| Max drawdown | Clearly stated and survivable |
| Profit factor | Above ~1.3 over many trades |
| Logic | Uses stop losses, no endless averaging down |
Wick says
A robot follows rules perfectly. Make sure they're good rules.
Key takeaways
- Automation removes emotion, not risk.
- Avoid martingale/grid systems without hard stops.
- Check prop firm EA rules before running one on a challenge.