Algorithmic trading system based on the MetaTrader4 online trading terminal using the built-in programming language MetaQuotes Language 4 are considered in this article. The mechanical trading system based on the Bollinger Bands indicator are considered. The main blocks of automated trading system have described. The results of system testing on historical data are given. The developed algorithmic trading system allows you to carry out transactions in financial markets automatically, that is, without human participation.

Keywords: automation, programming, financial markets, technical analysis, trading method, trading system, algorithmic trading