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れんみぃ
06/21/2026 18:30
Release： 06/21/2026 18:30
Update： 06/21/2026 18:30
れんみぃ
Investment style : Trading System
Investment career : More than 10 years
Investment amount : 10 million - 50 million JPY
I’ve been trading for about 11 years with almost no discretion. I’m the kind of person who spends all my time playing around with my own Expert Advisor.
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EA's Recommendation 12: For those who are thinking of starting EA development, discussing an introduction to MQL4 and MQL5 and how to set up the development environment

Good morning everyone. This is Renmi.

This is the 12th article. We’ve been talking from the perspective of those who use EAs, but this time I’ll shift the view a little and talk for those who are interested in “creating EAs.”

The previous article is here.

https://www.gogojungle.co.jp/finance/navi/articles/117665


For those who want to create an EA themselves or have a bit of programming ability but are new to EA development, I’ll honestly share what it’s like as a developer.

What you need for EA development

An EA (Expert Advisor) is a program that runs on MT4 or MT5,written in the dedicated languagecalled MQL4/MQL5.

This is all you need at the outset.

  • MT4 or MT5 (free)

  • MetaEditor (the development environment bundled with MT4/MT5, free)

  • Motivation

There is zero cost for setting up the environment. If you install MT4 or MT5, MetaEditor comes with it too.

From which should you start, MQL4 or MQL5

To be honest,if you want to build properly, MQL5 is the better choice.

MQL4 is for MT4, and MQL5 is for MT5. MQL5 has more features, higher backtest accuracy, and will be the mainstream in the future. If possible, I recommend developing with MQL5.

However, at the stage of “just want to move something simple first,” there is truth in the fact that MQL4 has more information available and is easier to start with. As a first step, you can start with MQL4 and then move to MQL5 as you get used to it.

As a side note, GTX I sell is still in MQL4. I’m gradually working on MQL5 support, which honestly is a kind of personal homework for me (lol).

Which EA to build first

In the beginning, it’s important to narrow the logic to something simple.

What I recommend isan EA that trades based on moving average crossovers— a simple, textbook-style logic like “when the short-term MA crosses above the long-term MA, buy; when it crosses below, sell.”

The reason is that the simpler the logic, the easier it is to identify the reasons why it might not move. If you start with a complex system, even if there are bugs, you won’t know the cause.

Make something that works → verify with backtesting → gradually refine

This cycle is the basic rhythm of EA development.

Learning resources

The following are helpful when learning MQL4/MQL5.

  • MQL4/MQL5 Reference(MetaEditor help): Official documentation of function lists. It’s in English, but machine translation can be used

  • MQL5.com forumsDevelopers from around the world share code

  • Japanese blogs and YouTubeSearch for “MQL4 入門” or “MQL5 入門” for many explanatory articles

With basic programming knowledge (variables, conditionals, loops), you can create a basic EA in a few weeks.

There is also a way to create EAs using AI

For those who say, “I have no programming skills, but I want to create an EA,”have AI write the codeas another option.

If you instruct ChatGPT, etc., to “create an EA with a certain logic in MQL4,” it will output reasonable code. It’s an effective way to obtain a working EA in a short time.

However,this is important— it is essential to properly understand the content of the code that appears.

If you keep using it without understanding, when bugs appear you won’t be able to fix them, or when market conditions change you won’t know what to adjust. It becomes like you’re running a black-box EA.

AI is, at its core, a tool to speed up coding. It is not a tool to skip understanding.

What I feel after becoming a developer

My motivation to start EA development was simply, “I want to create an EA I can trust myself.”

Once you can develop, you can see the quality of EAs on the market. You can judge things like “this backtest looks overfitted” or “this logic may fail as market conditions change,” at the code level.

Both as a user and as a creator, knowledge of MQL becomes a weapon.

By the way, GTX that I sell on GogoJungle is also an EA developed in MQL4. I’ll share my experience of doing development and sales as a single person in another article.

Summary

  • The environment setup cost for EA development is zero. You can start with MT4/MT5 and MetaEditor

  • If possible, MQL5 is recommended. If you just want to try something simple, you can start with MQL4

  • In the beginning, build a simple logic (MA cross, etc.)

  • Create something that works, backtest it, and iterate to improve — this is the basic cycle

  • Generating code with AI is acceptable, but understanding the content is mandatory

You might think “this looks difficult,” but with programming experience you can make something that works faster than you expect. If you’re interested, start by opening MetaEditor.

Well then, see you next time!

Renmi’s EA list

https://www.gogojungle.co.jp/users/189446/products