Using TCP Sockets for Two-Way Communication with MetaTrader 5
Summary
This article introduces sockets as a way to exchange data between MetaTrader 5 and external programs in both directions. It contrasts TCP stream sockets, which aim to deliver data reliably and in order, with UDP datagram sockets, which prioritize speed while allowing messages to be lost or arrive out of order. The examples frame sockets as a means to feed externally generated analysis or signals into an Expert Advisor or other chart application.
The practical demonstration uses MQL5 for a client and an external server, with a simple echo server that returns the data it receives. MetaTrader requires the user to allow the relevant external connection before the client can connect. The article presents this as introductory material for later replay and simulator development, rather than a complete trading system. Its server handles only one connection and is not designed for continued use, and the discussion does not compare socket performance or establish a trading advantage.
Key ideas
- Sockets can provide bidirectional data exchange between MetaTrader 5 and external applications.
- TCP is suited to ordered, reliable communication, while UDP can be faster but does not guarantee delivery or order.
- An external program can send analysis or signal data for an MQL5 application to use.
- The demonstration pairs an MQL5 client with a limited echo server that handles one connection.
- MetaTrader requires explicit permission for connections to servers beyond its trading server.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.