MQL4 and MQL5 Programming Articles

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Study the MQL5 language for programming trading strategies in numerous published articles mostly written by you - the community members. The articles are grouped into categories to help you quicker find answers to any questions related to programming: Integration, Tester, Trading Strategies, etc.

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DoEasy. Controls (Part 33): Vertical ScrollBar

DoEasy. Controls (Part 33): Vertical ScrollBar

In this article, we will continue the development of graphical elements of the DoEasy library and add vertical scrolling of form object controls, as well as some useful functions and methods that will be required in the future.
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From Basic to Intermediate: Array (IV)

From Basic to Intermediate: Array (IV)

In this article, we'll look at how you can do something very similar to what's implemented in languages like C, C++, and Java. I am talking about passing a virtually infinite number of parameters inside a function or procedure. While this may seem like a fairly advanced topic, in my opinion, what will be shown here can be easily implemented by anyone who has understood the previous concepts. Provided that they were really properly understood.
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Population optimization algorithms: Artificial Multi-Social Search Objects (MSO)

Population optimization algorithms: Artificial Multi-Social Search Objects (MSO)

This is a continuation of the previous article considering the idea of social groups. The article explores the evolution of social groups using movement and memory algorithms. The results will help to understand the evolution of social systems and apply them in optimization and search for solutions.
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Forecasting exchange rates using classic machine learning methods: Logit and Probit models

Forecasting exchange rates using classic machine learning methods: Logit and Probit models

In the article, an attempt is made to build a trading EA for predicting exchange rate quotes. The algorithm is based on classical classification models - logistic and probit regression. The likelihood ratio criterion is used as a filter for trading signals.
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Developing a Replay System (Part 65): Playing the service (VI)

Developing a Replay System (Part 65): Playing the service (VI)

In this article, we will look at how to implement and solve the mouse pointer issue when using it in conjunction with a replay/simulation application. The content presented here is intended solely for educational purposes. Under no circumstances should the application be viewed for any purpose other than to learn and master the concepts presented.
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MetaTrader tick info access from MQL5 services to Python application using sockets

MetaTrader tick info access from MQL5 services to Python application using sockets

Sometimes everything is not programmable in the MQL5 language. And even if it is possible to convert existing advanced libraries in MQL5, it would be time-consuming. This article tries to show that we can bypass Windows OS dependency by transporting tick information such as bid, ask and time with MetaTrader services to a Python application using sockets.
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MQL5 Trading Tools (Part 7): Informational Dashboard for Multi-Symbol Position and Account Monitoring

MQL5 Trading Tools (Part 7): Informational Dashboard for Multi-Symbol Position and Account Monitoring

In this article, we develop an informational dashboard in MQL5 for monitoring multi-symbol positions and account metrics like balance, equity, and free margin. We implement a sortable grid with real-time updates, CSV export, and a glowing header effect to enhance usability and visual appeal.
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Generative Adversarial Networks (GANs) for Synthetic Data in Financial Modeling (Part 2): Creating Synthetic Symbol for Testing

Generative Adversarial Networks (GANs) for Synthetic Data in Financial Modeling (Part 2): Creating Synthetic Symbol for Testing

In this article we are creating a synthetic symbol using a Generative Adversarial Network (GAN) involves generating realistic Financial data that mimics the behavior of actual market instruments, such as EURUSD. The GAN model learns patterns and volatility from historical market data and creates synthetic price data with similar characteristics.
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From Basic to Intermediate: Arrays and Strings (III)

From Basic to Intermediate: Arrays and Strings (III)

This article considers two aspects. First, how the standard library can convert binary values to other representations such as octal, decimal, and hexadecimal. Second, we will talk about how we can determine the width of our password based on the secret phrase, using the knowledge we have already acquired.
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MQL5 Wizard Techniques you should know (Part 47): Reinforcement Learning with Temporal Difference

MQL5 Wizard Techniques you should know (Part 47): Reinforcement Learning with Temporal Difference

Temporal Difference is another algorithm in reinforcement learning that updates Q-Values basing on the difference between predicted and actual rewards during agent training. It specifically dwells on updating Q-Values without minding their state-action pairing. We therefore look to see how to apply this, as we have with previous articles, in a wizard assembled Expert Advisor.
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Role of random number generator quality in the efficiency of optimization algorithms

Role of random number generator quality in the efficiency of optimization algorithms

In this article, we will look at the Mersenne Twister random number generator and compare it with the standard one in MQL5. We will also find out the influence of the random number generator quality on the results of optimization algorithms.
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Developing a Replay System (Part 30): Expert Advisor project — C_Mouse class (IV)

Developing a Replay System (Part 30): Expert Advisor project — C_Mouse class (IV)

Today we will learn a technique that can help us a lot in different stages of our professional life as a programmer. Often it is not the platform itself that is limited, but the knowledge of the person who talks about the limitations. This article will tell you that with common sense and creativity you can make the MetaTrader 5 platform much more interesting and versatile without resorting to creating crazy programs or anything like that, and create simple yet safe and reliable code. We will use our creativity to modify existing code without deleting or adding a single line to the source code.
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Self Optimizing Expert Advisors in MQL5 (Part 8): Multiple Strategy Analysis (2)

Self Optimizing Expert Advisors in MQL5 (Part 8): Multiple Strategy Analysis (2)

Join us for our follow-up discussion, where we will merge our first two trading strategies into an ensemble trading strategy. We shall demonstrate the different schemes possible for combining multiple strategies and also how to exercise control over the parameter space, to ensure that effective optimization remains possible even as our parameter size grows.
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From Basic to Intermediate: Passing by Value or by Reference

From Basic to Intermediate: Passing by Value or by Reference

In this article, we will practically understand the difference between passing by value and passing by reference. Although this seems like something simple and common and not causing any problems, many experienced programmers often face real failures in working on the code precisely because of this small detail. Knowing when, how, and why to use pass by value or pass by reference will make a huge difference in our lives as programmers. The content presented here is intended solely for educational purposes. Under no circumstances should the application be viewed for any purpose other than to learn and master the concepts presented.
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Mutual information as criteria for Stepwise Feature Selection

Mutual information as criteria for Stepwise Feature Selection

In this article, we present an MQL5 implementation of Stepwise Feature Selection based on the mutual information between an optimal predictor set and a target variable.
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Creating a Trading Administrator Panel in MQL5 (Part IV): Login Security Layer

Creating a Trading Administrator Panel in MQL5 (Part IV): Login Security Layer

Imagine a malicious actor infiltrating the Trading Administrator room, gaining access to the computers and the Admin Panel used to communicate valuable insights to millions of traders worldwide. Such an intrusion could lead to disastrous consequences, such as the unauthorized sending of misleading messages or random clicks on buttons that trigger unintended actions. In this discussion, we will explore the security measures in MQL5 and the new security features we have implemented in our Admin Panel to safeguard against these threats. By enhancing our security protocols, we aim to protect our communication channels and maintain the trust of our global trading community. Find more insights in this article discussion.
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Population optimization algorithms: Charged System Search (CSS) algorithm

Population optimization algorithms: Charged System Search (CSS) algorithm

In this article, we will consider another optimization algorithm inspired by inanimate nature - Charged System Search (CSS) algorithm. The purpose of this article is to present a new optimization algorithm based on the principles of physics and mechanics.
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MQL5 Wizard Techniques you should know (Part 33): Gaussian Process Kernels

MQL5 Wizard Techniques you should know (Part 33): Gaussian Process Kernels

Gaussian Process Kernels are the covariance function of the Normal Distribution that could play a role in forecasting. We explore this unique algorithm in a custom signal class of MQL5 to see if it could be put to use as a prime entry and exit signal.
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African Buffalo Optimization (ABO)

African Buffalo Optimization (ABO)

The article presents the African Buffalo Optimization (ABO) algorithm, a metaheuristic approach developed in 2015 based on the unique behavior of these animals. The article describes in detail the stages of the algorithm implementation and its efficiency in finding solutions to complex problems, which makes it a valuable tool in the field of optimization.
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Analyzing weather impact on currencies of agricultural countries using Python

Analyzing weather impact on currencies of agricultural countries using Python

What is the relationship between weather and Forex? Classical economic theory has long ignored the influence of such factors as weather on market behavior. But everything has changed. Let's try to find connections between the weather conditions and the position of agricultural currencies on the market.
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Developing a Replay System (Part 68): Getting the Time Right (I)

Developing a Replay System (Part 68): Getting the Time Right (I)

Today we will continue working on getting the mouse pointer to tell us how much time is left on a bar during periods of low liquidity. Although at first glance it seems simple, in reality this task is much more difficult. This involves some obstacles that we will have to overcome. Therefore, it is important that you have a good understanding of the material in this first part of this subseries in order to understand the following parts.
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Population optimization algorithms: Whale Optimization Algorithm (WOA)

Population optimization algorithms: Whale Optimization Algorithm (WOA)

Whale Optimization Algorithm (WOA) is a metaheuristic algorithm inspired by the behavior and hunting strategies of humpback whales. The main idea of WOA is to mimic the so-called "bubble-net" feeding method, in which whales create bubbles around prey and then attack it in a spiral motion.
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Data Science and ML (Part 36): Dealing with Biased Financial Markets

Data Science and ML (Part 36): Dealing with Biased Financial Markets

Financial markets are not perfectly balanced. Some markets are bullish, some are bearish, and some exhibit some ranging behaviors indicating uncertainty in either direction, this unbalanced information when used to train machine learning models can be misleading as the markets change frequently. In this article, we are going to discuss several ways to tackle this issue.
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ALGLIB library optimization methods (Part I)

ALGLIB library optimization methods (Part I)

In this article, we will get acquainted with the ALGLIB library optimization methods for MQL5. The article includes simple and clear examples of using ALGLIB to solve optimization problems, which will make mastering the methods as accessible as possible. We will take a detailed look at the connection of such algorithms as BLEIC, L-BFGS and NS, and use them to solve a simple test problem.
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An introduction to Receiver Operating Characteristic curves

An introduction to Receiver Operating Characteristic curves

ROC curves are graphical representations used to evaluate the performance of classifiers. Despite ROC graphs being relatively straightforward, there exist common misconceptions and pitfalls when using them in practice. This article aims to provide an introduction to ROC graphs as a tool for practitioners seeking to understand classifier performance evaluation.
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Reimagining Classic Strategies (Part 14): Multiple Strategy Analysis

Reimagining Classic Strategies (Part 14): Multiple Strategy Analysis

In this article, we continue our exploration of building an ensemble of trading strategies and using the MT5 genetic optimizer to tune the strategy parameters. Today, we analyzed the data in Python, showing our model could better predict which strategy would outperform, achieving higher accuracy than forecasting market returns directly. However, when we tested our application with its statistical models, our performance levels fell dismally. We subsequently discovered that the genetic optimizer unfortunately favored highly correlated strategies, prompting us to revise our method to keep vote weights fixed and focus optimization on indicator settings instead.
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Neural networks made easy (Part 63): Unsupervised Pretraining for Decision Transformer (PDT)

Neural networks made easy (Part 63): Unsupervised Pretraining for Decision Transformer (PDT)

We continue to discuss the family of Decision Transformer methods. From previous article, we have already noticed that training the transformer underlying the architecture of these methods is a rather complex task and requires a large labeled dataset for training. In this article we will look at an algorithm for using unlabeled trajectories for preliminary model training.
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Causal analysis of time series using transfer entropy

Causal analysis of time series using transfer entropy

In this article, we discuss how statistical causality can be applied to identify predictive variables. We will explore the link between causality and transfer entropy, as well as present MQL5 code for detecting directional transfers of information between two variables.
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From Novice to Expert: Animated News Headline Using MQL5 (VII) — Post Impact Strategy for News Trading

From Novice to Expert: Animated News Headline Using MQL5 (VII) — Post Impact Strategy for News Trading

The risk of whipsaw is extremely high during the first minute following a high-impact economic news release. In that brief window, price movements can be erratic and volatile, often triggering both sides of pending orders. Shortly after the release—typically within a minute—the market tends to stabilize, resuming or correcting the prevailing trend with more typical volatility. In this section, we’ll explore an alternative approach to news trading, aiming to assess its effectiveness as a valuable addition to a trader’s toolkit. Continue reading for more insights and details in this discussion.
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Redefining MQL5 and MetaTrader 5 Indicators

Redefining MQL5 and MetaTrader 5 Indicators

An innovative approach to collecting indicator information in MQL5 enables more flexible and streamlined data analysis by allowing developers to pass custom inputs to indicators for immediate calculations. This approach is particularly useful for algorithmic trading, as it provides enhanced control over the information processed by indicators, moving beyond traditional constraints.
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MQL5 Wizard Techniques you should know (Part 63): Using Patterns of DeMarker and Envelope Channels

MQL5 Wizard Techniques you should know (Part 63): Using Patterns of DeMarker and Envelope Channels

The DeMarker Oscillator and the Envelopes' indicator are momentum and support/resistance tools that can be paired when developing an Expert Advisor. We therefore examine on a pattern by pattern basis what could be of use and what potentially avoid. We are using, as always, a wizard assembled Expert Advisor together with the Patterns-Usage functions that are built into the Expert Signal Class.
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From Basic to Intermediate: Operator Precedence

From Basic to Intermediate: Operator Precedence

This is definitely the most difficult question to be explained purely theoretically. That is why you need to practice everything that we're going to discuss here. While this may seem simple at first, the topic of operators can only be understood in practice combined with constant education.
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Population optimization algorithms: Micro Artificial immune system (Micro-AIS)

Population optimization algorithms: Micro Artificial immune system (Micro-AIS)

The article considers an optimization method based on the principles of the body's immune system - Micro Artificial Immune System (Micro-AIS) - a modification of AIS. Micro-AIS uses a simpler model of the immune system and simple immune information processing operations. The article also discusses the advantages and disadvantages of Micro-AIS compared to conventional AIS.
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Creating a Trading Administrator Panel in MQL5 (Part X): External resource-based interface

Creating a Trading Administrator Panel in MQL5 (Part X): External resource-based interface

Today, we are harnessing the capabilities of MQL5 to utilize external resources—such as images in the BMP format—to create a uniquely styled home interface for the Trading Administrator Panel. The strategy demonstrated here is particularly useful when packaging multiple resources, including images, sounds, and more, for streamlined distribution. Join us in this discussion as we explore how these features are implemented to deliver a modern and visually appealing interface for our New_Admin_Panel EA.
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Developing an MQL5 RL agent with RestAPI integration (Part 4): Organizing functions in classes in MQL5

Developing an MQL5 RL agent with RestAPI integration (Part 4): Organizing functions in classes in MQL5

This article discusses the transition from procedural coding to object-oriented programming (OOP) in MQL5 with an emphasis on integration with the REST API. Today we will discuss how to organize HTTP request functions (GET and POST) into classes. We will take a closer look at code refactoring and show how to replace isolated functions with class methods. The article contains practical examples and tests.
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Price Action Analysis Toolkit Development (Part 34): Turning Raw Market Data into Predictive Models Using an Advanced Ingestion Pipeline

Price Action Analysis Toolkit Development (Part 34): Turning Raw Market Data into Predictive Models Using an Advanced Ingestion Pipeline

Have you ever missed a sudden market spike or been caught off‑guard when one occurred? The best way to anticipate live events is to learn from historical patterns. Intending to train an ML model, this article begins by showing you how to create a script in MetaTrader 5 that ingests historical data and sends it to Python for storage—laying the foundation for your spike‑detection system. Read on to see each step in action.
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Causal inference in time series classification problems

Causal inference in time series classification problems

In this article, we will look at the theory of causal inference using machine learning, as well as the custom approach implementation in Python. Causal inference and causal thinking have their roots in philosophy and psychology and play an important role in our understanding of reality.
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MQL5 Wizard Techniques you should know (Part 20): Symbolic Regression

MQL5 Wizard Techniques you should know (Part 20): Symbolic Regression

Symbolic Regression is a form of regression that starts with minimal to no assumptions on what the underlying model that maps the sets of data under study would look like. Even though it can be implemented by Bayesian Methods or Neural Networks, we look at how an implementation with Genetic Algorithms can help customize an expert signal class usable in the MQL5 wizard.
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Overcoming The Limitation of Machine Learning (Part 2): Lack of Reproducibility

Overcoming The Limitation of Machine Learning (Part 2): Lack of Reproducibility

The article explores why trading results can differ significantly between brokers, even when using the same strategy and financial symbol, due to decentralized pricing and data discrepancies. The piece helps MQL5 developers understand why their products may receive mixed reviews on the MQL5 Marketplace, and urges developers to tailor their approaches to specific brokers to ensure transparent and reproducible outcomes. This could grow to become an important domain-bound best practice that will serve our community well if the practice were to be widely adopted.
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Developing a Replay System (Part 64): Playing the service (V)

Developing a Replay System (Part 64): Playing the service (V)

In this article, we will look at how to fix two errors in the code. However, I will try to explain them in a way that will help you, beginner programmers, understand that things don't always go as you expect. Anyway, this is an opportunity to learn. The content presented here is intended solely for educational purposes. In no way should this application be considered as a final document with any purpose other than to explore the concepts presented.