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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Formulating Dynamic Multi-Pair EA (Part 7): Cross-Pair Correlation Mapping for Real-Time Trade Filtering

Formulating Dynamic Multi-Pair EA (Part 7): Cross-Pair Correlation Mapping for Real-Time Trade Filtering

In this part, we will integrate a real-time correlation matrix into a multi-symbol Expert Advisor to prevent redundant or risk-stacked trades. By dynamically measuring cross-pair relationships, the EA will filter entries that conflict with existing exposure, improving portfolio balance, reducing systemic risk, and enhancing overall trade quality.
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Hidden Markov Models in Machine Learning-Based Trading Systems

Hidden Markov Models in Machine Learning-Based Trading Systems

Hidden Markov Models (HMMs) are a powerful class of probabilistic models designed to analyze sequential data, where observed events depend on some sequence of unobserved (hidden) states that form a Markov process. The main assumptions of HMM include the Markov property for hidden states, meaning that the probability of transition to the next state depends only on the current state, and the independence of observations given knowledge of the current hidden state.
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MQL5 Wizard Techniques you should know (Part 62): Using Patterns of ADX and CCI with Reinforcement-Learning TRPO

MQL5 Wizard Techniques you should know (Part 62): Using Patterns of ADX and CCI with Reinforcement-Learning TRPO

The ADX Oscillator and CCI oscillator are trend following and momentum indicators that can be paired when developing an Expert Advisor. We continue where we left off in the last article by examining how in-use training, and updating of our developed model, can be made thanks to reinforcement-learning. We are using an algorithm we are yet to cover in these series, known as Trusted Region Policy Optimization. And, as always, Expert Advisor assembly by the MQL5 Wizard allows us to set up our model(s) for testing much quicker and also in a way where it can be distributed and tested with different signal types.
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Developing a Replay System — Market simulation (Part 07): First improvements (II)

Developing a Replay System — Market simulation (Part 07): First improvements (II)

In the previous article, we made some fixes and added tests to our replication system to ensure the best possible stability. We also started creating and using a configuration file for this system.
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Market Simulation (Part 16): Sockets (X)

Market Simulation (Part 16): Sockets (X)

We are close to completing this challenge. However, before we begin, I want you to try to understand these two articles—this one and the previous one. That way, you will truly understand the next article, in which I will cover exclusively the part related to MQL5 programming. But I will also try to make it understandable. If you do not understand these last two articles, it will be difficult for you to understand the next one, because the material accumulates. The more things there are to do, the more you need to create and understand in order to achieve the goal.
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Neural Networks in Trading: A Hybrid Trading Framework with Predictive Coding (Final Part)

Neural Networks in Trading: A Hybrid Trading Framework with Predictive Coding (Final Part)

We continue our examination of the StockFormer hybrid trading system, which combines predictive coding and reinforcement learning algorithms for financial time series analysis. The system is based on three Transformer branches with a Diversified Multi-Head Attention (DMH-Attn) mechanism that enables the capturing of complex patterns and interdependencies between assets. Previously, we got acquainted with the theoretical aspects of the framework and implemented the DMH-Attn mechanisms. Today, we will talk about the model architecture and training.
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Markets Positioning Codex in MQL5 (Part 1): Bitwise Learning for Nvidia

Markets Positioning Codex in MQL5 (Part 1): Bitwise Learning for Nvidia

We commence a new article series that builds upon our earlier efforts laid out in the MQL5 Wizard series, by taking them further as we step up our approach to systematic trading and strategy testing. Within these new series, we’ll concentrate our focus on Expert Advisors that are coded to hold only a single type of position - primarily longs. Focusing on just one market trend can simplify analysis, lessen strategy complexity and expose some key insights, especially when dealing in assets beyond forex. Our series, therefore, will investigate if this is effective in equities and other non-forex assets, where long only systems usually correlate well with smart money or institution strategies.
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Creating a Trading Administrator Panel in MQL5 (Part XI): Modern feature communications interface (I)

Creating a Trading Administrator Panel in MQL5 (Part XI): Modern feature communications interface (I)

Today, we are focusing on the enhancement of the Communications Panel messaging interface to align with the standards of modern, high-performing communication applications. This improvement will be achieved by updating the CommunicationsDialog class. Join us in this article and discussion as we explore key insights and outline the next steps in advancing interface programming using MQL5.
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Statistical Arbitrage Through Cointegrated Stocks (Part 3): Database Setup

Statistical Arbitrage Through Cointegrated Stocks (Part 3): Database Setup

This article presents a sample MQL5 Service implementation for updating a newly created database used as source for data analysis and for trading a basket of cointegrated stocks. The rationale behind the database design is explained in detail and the data dictionary is documented for reference. MQL5 and Python scripts are provided for the database creation, schema initialization, and market data insertion.
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MetaTrader 5 Machine Learning Blueprint (Part 7): From Scattered Experiments to Reproducible Results

MetaTrader 5 Machine Learning Blueprint (Part 7): From Scattered Experiments to Reproducible Results

In the latest installment of this series, we move beyond individual machine learning techniques to address the "Research Chaos" that plagues many quantitative traders. This article focuses on the transition from ad-hoc notebook experiments to a principled, production-grade pipeline that ensures reproducibility, traceability, and efficiency.
All about Automated Trading Championship: Registration
All about Automated Trading Championship: Registration

All about Automated Trading Championship: Registration

This article comprises useful materials that will help you learn more about the procedure of registration for participation in the Automated Trading Championship.
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Visualizing deals on a chart (Part 1): Selecting a period for analysis

Visualizing deals on a chart (Part 1): Selecting a period for analysis

Here we are going to develop a script from scratch that simplifies unloading print screens of deals for analyzing trading entries. All the necessary information on a single deal is to be conveniently displayed on one chart with the ability to draw different timeframes.
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Neural Networks in Trading: Models Using Wavelet Transform and Multi-Task Attention

Neural Networks in Trading: Models Using Wavelet Transform and Multi-Task Attention

We invite you to explore a framework that combines wavelet transforms and a multi-task self-attention model, aimed at improving the responsiveness and accuracy of forecasting in volatile market conditions. The wavelet transform allows asset returns to be decomposed into high and low frequencies, carefully capturing long-term market trends and short-term fluctuations.
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Population optimization algorithms: Resistance to getting stuck in local extrema (Part II)

Population optimization algorithms: Resistance to getting stuck in local extrema (Part II)

We continue our experiment that aims to examine the behavior of population optimization algorithms in the context of their ability to efficiently escape local minima when population diversity is low and reach global maxima. Research results are provided.
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MQL5 Wizard Techniques you should know (Part 76):  Using Patterns of Awesome Oscillator and the Envelope Channels with Supervised Learning

MQL5 Wizard Techniques you should know (Part 76): Using Patterns of Awesome Oscillator and the Envelope Channels with Supervised Learning

We follow up on our last article, where we introduced the indicator couple of the Awesome-Oscillator and the Envelope Channel, by looking at how this pairing could be enhanced with Supervised Learning. The Awesome-Oscillator and Envelope-Channel are a trend-spotting and support/resistance complimentary mix. Our supervised learning approach is a CNN that engages the Dot Product Kernel with Cross-Time-Attention to size its kernels and channels. As per usual, this is done in a custom signal class file that works with the MQL5 wizard to assemble an Expert Advisor.
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Adaptive Social Behavior Optimization (ASBO): Schwefel, Box-Muller Method

Adaptive Social Behavior Optimization (ASBO): Schwefel, Box-Muller Method

This article provides a fascinating insight into the world of social behavior in living organisms and its influence on the creation of a new mathematical model - ASBO (Adaptive Social Behavior Optimization). We will examine how the principles of leadership, neighborhood, and cooperation observed in living societies inspire the development of innovative optimization algorithms.
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From Basic to Intermediate: Recursion

From Basic to Intermediate: Recursion

In this article we will look at a very interesting and quite challenging programming concept, although it should be treated with great caution, as its misuse or misunderstanding can turn relatively simple programs into something unnecessarily complex. But when used correctly and adapted perfectly to equally suitable situations, recursion becomes an excellent ally in solving problems that would otherwise be much more laborious and time-consuming. The materials presented here are intended for educational purposes only. Under no circumstances should the application be viewed for any purpose other than to learn and master the concepts presented.
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Developing a Replay System (Part 72): An Unusual Communication (I)

Developing a Replay System (Part 72): An Unusual Communication (I)

What we create today will be difficult to understand. Therefore, in this article I will only talk about the initial stage. Please read this article carefully, it is an important prerequisite before we proceed to the next step. The purpose of this material is purely didactic as we will only study and master the presented concepts, without practical application.
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MQL5 Wizard Techniques you should know (Part 45): Reinforcement Learning with Monte-Carlo

MQL5 Wizard Techniques you should know (Part 45): Reinforcement Learning with Monte-Carlo

Monte-Carlo is the fourth different algorithm in reinforcement learning that we are considering with the aim of exploring its implementation in wizard assembled Expert Advisors. Though anchored in random sampling, it does present vast ways of simulation which we can look to exploit.
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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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Bivariate Copulae in MQL5 (Part 2): Implementing Archimedean copulae in MQL5

Bivariate Copulae in MQL5 (Part 2): Implementing Archimedean copulae in MQL5

In the second installment of the series, we discuss the properties of bivariate Archimedean copulae and their implementation in MQL5. We also explore applying copulae to the development of a simple pairs trading strategy.
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Three MACD Filters on US_TECH100: Five Years of Broker Data

Three MACD Filters on US_TECH100: Five Years of Broker Data

This article tests three common filters on a standard MACD crossover for US_TECH100 H1 using five years of broker-native data. Filters are layered incrementally: regime, higher timeframe (HTF) alignment, and US session timing, to isolate each one's marginal impact. Results show session timing contributes far more than indicator refinements, while regime and HTF add little on their own. Includes a reproducible MQL5 regime classifier.
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Resampling techniques for prediction and classification assessment in MQL5

Resampling techniques for prediction and classification assessment in MQL5

In this article, we will explore and implement, methods for assessing model quality that utilize a single dataset as both training and validation sets.
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Introduction to MQL5 (Part 30): Mastering API and WebRequest Function in MQL5 (IV)

Introduction to MQL5 (Part 30): Mastering API and WebRequest Function in MQL5 (IV)

Discover a step-by-step tutorial that simplifies the extraction, conversion, and organization of candle data from API responses within the MQL5 environment. This guide is perfect for newcomers looking to enhance their coding skills and develop robust strategies for managing market data efficiently.
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Developing a Replay System (Part 47): Chart Trade Project (VI)

Developing a Replay System (Part 47): Chart Trade Project (VI)

Finally, our Chart Trade indicator starts interacting with the EA, allowing information to be transferred interactively. Therefore, in this article, we will improve the indicator, making it functional enough to be used together with any EA. This will allow us to access the Chart Trade indicator and work with it as if it were actually connected with an EA. But we will do it in a much more interesting way than before.
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MQL5 Trading Tools (Part 24): Depth-Perception Upgrades with 3D Curves, Pan Mode, and ViewCube Navigation

MQL5 Trading Tools (Part 24): Depth-Perception Upgrades with 3D Curves, Pan Mode, and ViewCube Navigation

In this article, we enhance the 3D binomial distribution graphing tool in MQL5 by adding a segmented 3D curve for improved depth perception of the probability mass function, integrating pan mode for view target shifting, and implementing an interactive view cube with hover zones and animations for quick orientation changes. We incorporate clickable sub-zones on the view cube for faces, edges, and corners to animate camera transitions to standard views, while maintaining switchable 2D/3D modes, real-time updates, and customizable parameters for immersive probabilistic analysis in trading.
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Visual assessment and adjustment of trading in MetaTrader 5

Visual assessment and adjustment of trading in MetaTrader 5

The strategy tester allows you to do more than just optimize your trading robot's parameters. I will show how to evaluate your account's trading history post-factum and make adjustments to your trading in the tester by changing the stop-losses of your open positions.
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Integrating MQL5 with Data Processing Packages (Part 7): Building Multi-Agent Environments for Cross-Symbol Collaboration

Integrating MQL5 with Data Processing Packages (Part 7): Building Multi-Agent Environments for Cross-Symbol Collaboration

The article presents a complete Python–MQL5 integration for multi‑agent trading: MT5 data ingestion, indicator computation, per‑agent decisions, and a weighted consensus that outputs a single action. Signals are stored to JSON, served by Flask, and consumed by an MQL5 Expert Advisor for execution with position sizing and ATR‑derived SL/TP. Flask routes provide safe lifecycle control and status monitoring.
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Population optimization algorithms: Boids Algorithm

Population optimization algorithms: Boids Algorithm

The article considers Boids algorithm based on unique examples of animal flocking behavior. In turn, the Boids algorithm serves as the basis for the creation of the whole class of algorithms united under the name "Swarm Intelligence".
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Neural Networks in Trading: Detecting Anomalies in the Frequency Domain (CATCH)

Neural Networks in Trading: Detecting Anomalies in the Frequency Domain (CATCH)

The CATCH framework combines Fourier transform and frequency patching to accurately identify market anomalies beyond the reach of traditional methods. Let us examine how this approach reveals hidden patterns in financial data.
How to Become a Participant of Automated Trading Championship 2008?
How to Become a Participant of Automated Trading Championship 2008?

How to Become a Participant of Automated Trading Championship 2008?

The main purpose of the Championship is to popularize automated trading and accumulate practical information in this field of knowledge. As the Organizer of the Championship, we are doing our best to provide a fair competition and suppress all attempts to “play booty”. It is this reasoning that sets the strict Rules of the Championship.
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From Novice to Expert: Market Periods Synchronizer

From Novice to Expert: Market Periods Synchronizer

In this discussion, we introduce a Higher-to-Lower Timeframe Synchronizer tool designed to solve the problem of analyzing market patterns that span across higher timeframe periods. The built-in period markers in MetaTrader 5 are often limited, rigid, and not easily customizable for non-standard timeframes. Our solution leverages the MQL5 language to develop an indicator that provides a dynamic and visual way to align higher timeframe structures within lower timeframe charts. This tool can be highly valuable for detailed market analysis. To learn more about its features and implementation, I invite you to join the discussion.
Idleness is the Stimulus to Progress, or How to Work with Graphics Interacively
Idleness is the Stimulus to Progress, or How to Work with Graphics Interacively

Idleness is the Stimulus to Progress, or How to Work with Graphics Interacively

An indicator for interactive working with trend lines, Fibo levels, icons manually imposed on a chart. It allows you to draw the colored zones of Fibo levels, shows the moments of the price crossing the trend line, manages the "Price label" object.
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MQL5 Wizard Techniques you should know (Part 34): Price-Embedding with an Unconventional RBM

MQL5 Wizard Techniques you should know (Part 34): Price-Embedding with an Unconventional RBM

Restricted Boltzmann Machines are a form of neural network that was developed in the mid 1980s at a time when compute resources were prohibitively expensive. At its onset, it relied on Gibbs Sampling and Contrastive Divergence in order to reduce dimensionality or capture the hidden probabilities/properties over input training data sets. We examine how Backpropagation can perform similarly when the RBM ‘embeds’ prices for a forecasting Multi-Layer-Perceptron.
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Overcoming The Limitation of Machine Learning (Part 3): A Fresh Perspective on Irreducible Error

Overcoming The Limitation of Machine Learning (Part 3): A Fresh Perspective on Irreducible Error

This article takes a fresh perspective on a hidden, geometric source of error that quietly shapes every prediction your models make. By rethinking how we measure and apply machine learning forecasts in trading, we reveal how this overlooked perspective can unlock sharper decisions, stronger returns, and a more intelligent way to work with models we thought we already understood.
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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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Simplifying Databases in MQL5 (Part 2): Using metaprogramming to create entities

Simplifying Databases in MQL5 (Part 2): Using metaprogramming to create entities

We explored the advanced use of #define for metaprogramming in MQL5, creating entities that represent tables and column metadata (type, primary key, auto-increment, nullability, etc.). We centralized these definitions in TickORM.mqh, automating the generation of metadata classes and paving the way for efficient data manipulation by the ORM, without having to write SQL manually.
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Developing a Replay System (Part 62): Playing the service (III)

Developing a Replay System (Part 62): Playing the service (III)

In this article, we will begin to address the issue of tick excess that can impact application performance when using real data. This excess often interferes with the correct timing required to construct a one-minute bar in the appropriate window.
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The case for using a Composite Data Set this Q4 in weighing SPDR XLY's next performance

The case for using a Composite Data Set this Q4 in weighing SPDR XLY's next performance

We consider XLY, SPDR’s consumer discretionary spending ETF and see if with tools in MetaTrader’s IDE we can sift through an array of data sets in selecting what could work with a forecasting model with a forward outlook of not more than a year.
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From Basic to Intermediate: Array (II)

From Basic to Intermediate: Array (II)

In this article, we will look at what a dynamic array and a static array are. Is there a difference between using one or the other? Or are they always the same? When should you use one and when the other type? And what about constant arrays? We will try to understand what they are designed for and consider the risks of not initializing all the values in the array.