Expert Advisors (EAs) are software programs written in MetaQuotes language (MQL), that can be used to automate trading on the MetaTrader 4 and 5 (MT4/MT5) platforms.

EAs use different algorithms to monitor and trade financial markets. They follow predefined parameters to identify opportunities and can either notify you or automatically open a position. Expert Advisors can also set conditions for closing positions, such as stops, trailing stops, and limits.

Expert Advisors work by allowing you to define rules for finding opportunities and making trading decisions, and use complex mathematical models that combine multiple yes/no rules. This enables them to execute advanced trading strategies and make quick decisions based on computational power.

According to their trading strategies, EAs are usually classified within:

• Scalpers: These Expert Advisors aim to capture small profits whenever they become available. They continuously open and close trades, depending on market conditions.

• Hedge EAs: These Expert Advisors engage in hedging strategies by taking two opposing positions. This approach helps to mitigate losses in one position while facilitating profits in the other.

• News EAs: As the name suggests, the primary objective of these Expert Advisors is to capitalize on news events and significant price movements that occur during major news releases.

• Breakout EAs: These Expert Advisors are specifically designed to initiate trades when the price breaks through predefined resistance and support levels.

• Grid EAs: Grid trading is a trading system that involves using multiple orders to average the open price. Typically, the trading grid adds new positions to existing ones when they start experiencing losses.