Tools like or Ghidra (with custom MQL4 loaders) can show the assembly-level logic. This requires deep expertise but produces accurate, malware-free output.
Decompilation might be ethically acceptable if:
Obfuscation transforms your MQL4 code into a form that's much harder for humans to understand while maintaining functionality:
If you have an old EA (check the file date; pre-2014 is safe), here’s how to use the classic decompiler:
Many marketplaces and developers selling MQL4/EX4 programs include specific terms of service or End-User License Agreements (EULAs) that explicitly . Violating these terms can lead to legal action.
Software, including MQL4 indicators and EAs, is typically protected by copyright law. The creator of the MQL4 code holds the copyright. Decompiling an EX4 file to obtain the source code, especially for redistribution or creating derivative works without explicit permission, is a .
Most commercial EAs are protected by copyright. Decompiling them to steal the logic or remove a license check is software piracy. Developers spend hundreds of hours coding; using a decompiler to steal their work is illegal in most jurisdictions and violates MetaQuotes’ terms of service.
Many downloadable utilities found on unverified forums or sketchy file-sharing sites are Trojan horses. Once executed, they can install ransomware, lock files, or steal sensitive personal information.
Human-readable code written in MQL4, which can be edited in the MetaEditor.
For developers who prefer working from the command line, there's an unofficial CLI wrapper called ex4_to_mq4_cli available on GitHub. : This is a wrapper, not the decompiler itself! It requires the actual decompiler executable to function.
Free EX4 decompilers are largely a trap – technically obsolete, security hazards, and legally problematic. No reliable free solution exists for modern MT4 (build 600+).
If you write MQL4 code, always keep multiple backups of your .mq4 files in secure cloud storage.
Most free decompilers on YouTube or shady download sites are . They will: