MetaTrader 4, often called MT4, is a trading platform mainly used for forex but also supports CFDs for commodities, indices, and more. Developed by MetaQuotes in 2005, MT4 is designed with simplicity and functionality in mind, offering tools that help traders analyze price trends and execute trades efficiently. 

MT4 is best known for its technical analysis capabilities, including a wide variety of chart types and indicators to help traders analyze price trends. The platform supports automated trading through Expert Advisors (EAs), which are trading robots that execute trades based on pre-set conditions.  

MetaTrader 4 is also highly accessible, available on desktop, web, and mobile devices, allowing traders to stay connected to the market wherever they are. Its popularity has made it a standard in the forex trading community, with a wide network of educational resources and community support.