Using a Python-based tool (most reliable free option):
If you just want to learn, look for "Open Source" MQ4 indicators on the MQL5 codebase 6. The Better Alternative how to convert ex4 to mq4 free upd
Websites that ask you to upload your EX4 file to their server for a "free preview" of the MQ4 code often just steal your proprietary trading strategy and sell it to someone else. Using a Python-based tool (most reliable free option):
If your EX4 file is highly complex and you absolutely require the source code, you may have to look beyond free options. Professional decompilation services exist, but they are paid and carry risks. Professional decompilation services exist, but they are paid
They usually ask you to upload your EX4 file and provide an email address.
Most of these sites are automated traps. They will either present a paid paywall after you upload the file, send you corrupted data, or use the form to harvest your email and custom trading indicators. 2. Free Decompiler Software Downloads (The Danger)
Nevertheless, legitimate needs exist: