The client terminal includes a built-in editor and compiler with access to a user contributed free library of software, articles and help. The software utilizes a proprietary scripting language, MQL4, which enables traders to develop Expert Advisors, custom indicators and scripts. MetaTrader’s popularity largely stems from its support of algorithmic trading.
Yahoo! hosts a large group (over 12,000 members) devoted to development of free open source software for MetaTrader.
MT4 is designed to be used as a stand alone system with the broker manually managing their position and this is a common configuration used by brokers. However a number of third party developers have written software bridges enabling integration with other financial trading systems for automatic hedging of positions.
In late 2012 and early 2013, MetaQuotes Software began to work towards removing third-party plugins for its software from the market, suing and warning developers and brokers.