The relationship is akin to a C++ source file ( .cpp ) and its compiled binary ( .exe ). The .ex4 file is what gets distributed to users, allowing them to run the program without ever seeing the underlying logic.

Do not download or purchase this software. If you have lost the source code (

: For indicators, use the MetaTrader iCustom function to reference values from an EX4 file in your own code without needing the source.

Historically, tools targeting older builds of MetaTrader 4 claimed to decompile software using version identifiers like "4.0.432". However, MetaQuotes (the creator of MetaTrader) completely overhauled the MT4 compiler structure with the release of Build 600 and subsequent versions.