Expert advisor / algorithmic trading
A strategy with its rules written in code that runs automatically on a platform (MT4/MT5, cTrader, Python). It guarantees discipline, but not the quality of the rules.
Automation takes emotion out, runs 24 hours a day and makes backtesting easier. But the "buy a ready-made EA and make money" model is almost always overfit or martingale-based.
Coding your own rules is one of the best ways to pin down your strategy, and a VPS lets you run it without interruption.
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