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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Developing a Replay System (Part 45): Chart Trade Project (IV)

Developing a Replay System (Part 45): Chart Trade Project (IV)

The main purpose of this article is to introduce and explain the C_ChartFloatingRAD class. We have a Chart Trade indicator that works in a rather interesting way. As you may have noticed, we still have a fairly small number of objects on the chart, and yet we get the expected functionality. The values present in the indicator can be edited. The question is, how is this possible? This article will start to make things clearer.
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Adaptive Social Behavior Optimization (ASBO): Two-phase evolution

Adaptive Social Behavior Optimization (ASBO): Two-phase evolution

We continue dwelling on the topic of social behavior of living organisms and its impact on the development of a new mathematical model - ASBO (Adaptive Social Behavior Optimization). We will dive into the two-phase evolution, test the algorithm and draw conclusions. Just as in nature a group of living organisms join their efforts to survive, ASBO uses principles of collective behavior to solve complex optimization problems.
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Engineering Trading Discipline into Code (Part 6): Building a Unified Discipline Framework in MQL5

Engineering Trading Discipline into Code (Part 6): Building a Unified Discipline Framework in MQL5

The article introduces a unified MQL5 discipline framework that consolidates the symbol whitelist, trading‑hours and news filters, and daily trade‑limit modules under CDisciplineEngine.mqh. It explains centralized trade validation and state synchronization shared by a chart dashboard and an enforcement Expert Advisor. Readers learn how to authorize orders through a single gate, monitor permissions in real time, and automatically enforce rules across the terminal.
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Market Simulation (Part 12): Sockets (VI)

Market Simulation (Part 12): Sockets (VI)

In this article, we will look at how to solve certain problems and issues that arise when using Python code within other programs. More specifically, we will demonstrate a common issue encountered when using Excel in conjunction with MetaTrader 5, although we will be using Python to facilitate this interaction. However, this implementation has a minor drawback. It does not occur in all cases, but only in certain specific situations. When it does happen, it is necessary to understand the cause. In today’s article, we will begin explaining how to resolve this issue.
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Feature selection and dimensionality reduction using principal components

Feature selection and dimensionality reduction using principal components

The article delves into the implementation of a modified Forward Selection Component Analysis algorithm, drawing inspiration from the research presented in “Forward Selection Component Analysis: Algorithms and Applications” by Luca Puggini and Sean McLoone.
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Feature Engineering for ML (Part 2): Implementing Fixed-Width Fractional Differentiation in MQL5

Feature Engineering for ML (Part 2): Implementing Fixed-Width Fractional Differentiation in MQL5

This article delivers a production-grade MQL5 implementation of fixed-width fractional differentiation for live MetaTrader 5 feeds. We introduce a header-only CFFDEngine that precomputes weights without a fixed cap, performs O(width) per-bar updates, and avoids per-tick allocations. The FFD.mq5 indicator supports all ENUM_APPLIED_PRICE types and prev_calculated optimization. Validation scripts confirm numerical equivalence with the standard Python frac diff_ffd pipeline.
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The case for using Hospital-Performance Data with Perceptrons, this Q4, in weighing SPDR XLV's next Performance

The case for using Hospital-Performance Data with Perceptrons, this Q4, in weighing SPDR XLV's next Performance

XLV is SPDR healthcare ETF and in an age where it is common to be bombarded by a wide array of traditional news items plus social media feeds, it can be pressing to select a data set for use with a model. We try to tackle this problem for this ETF by sizing up some of its critical data sets in MQL5.
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MQL5 Wizard Techniques you should know (Part 88): Using Blooms Filter with a Custom Trailing Class

MQL5 Wizard Techniques you should know (Part 88): Using Blooms Filter with a Custom Trailing Class

Our next focus in these series on ideas that can be rapidly prototyped with the MQL5 Wizard, is a Custom Trailing class that uses the Blooming Filter. Trailing Stop systems are an optional but very resourceful part to any trading system that we want to explore more in these series besides the traditional Entry Signals.
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Developing a Replay System (Part 35): Making Adjustments (I)

Developing a Replay System (Part 35): Making Adjustments (I)

Before we can move forward, we need to fix a few things. These are not actually the necessary fixes but rather improvements to the way the class is managed and used. The reason is that failures occurred due to some interaction within the system. Despite attempts to find out the cause of such failures in order to eliminate them, all these attempts were unsuccessful. Some of these cases make no sense, for example, when we use pointers or recursion in C/C++, the program crashes.
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Feature Engineering for ML (Part 2): Implementing Fixed-Width Fractional Differentiation in MQL5

Feature Engineering for ML (Part 2): Implementing Fixed-Width Fractional Differentiation in MQL5

This article delivers a production-grade MQL5 implementation of fixed-width fractional differentiation for live MetaTrader 5 feeds. We introduce a header-only CFFDEngine that precomputes weights without a fixed cap, performs O(width) per-bar updates, and avoids per-tick allocations. The FFD.mq5 indicator supports all ENUM_APPLIED_PRICE types and prev_calculated optimization. Validation scripts confirm numerical equivalence with the standard Python frac diff_ffd pipeline.
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Bivariate Copulae in MQL5 (Part 3): Implementation and Tuning of Mixed Copula Models in MQL5

Bivariate Copulae in MQL5 (Part 3): Implementation and Tuning of Mixed Copula Models in MQL5

The article extends our copula toolkit with mixed copulas implemented natively in MQL5. We construct Clayton–Frank–Gumbel and Clayton–Student–t–Gumbel mixtures, estimate them via EM, and enable sparsity control through SCAD with cross‑validation. Provided scripts tune hyperparameters, compare mixtures using information criteria, and save trained models. Practitioners can apply these components to capture asymmetric tail dependence and embed the selected model in indicators or Expert Advisors.
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Developing a Replay System (Part 55): Control Module

Developing a Replay System (Part 55): Control Module

In this article, we will implement a control indicator so that it can be integrated into the message system we are developing. Although it is not very difficult, there are some details that need to be understood about the initialization of this module. The material presented here is for educational purposes only. In no way should it be considered as an application for any purpose other than learning and mastering the concepts shown.
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MQL5 Trading Tools (Part 25): Expanding to Multiple Distributions with Interactive Switching

MQL5 Trading Tools (Part 25): Expanding to Multiple Distributions with Interactive Switching

In this article, we expand the MQL5 graphing tool to support seventeen statistical distributions with interactive cycling via a header switch icon. We add type-specific data loading, discrete and continuous histogram computation, and theoretical density functions for each model, with dynamic titles, axis labels, and parameter panels that adapt automatically. The result lets you overlay distribution models on the same sample and compare fit across families without reloading the tool.
All about Automated Trading Championship: Reporting the Championship 2007
All about Automated Trading Championship: Reporting the Championship 2007

All about Automated Trading Championship: Reporting the Championship 2007

The present article contains Weekly Reports of the ATC 2007. These materials are like snapshots, they are interesting-to-read not only during the Championship, but years later as well.
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MQL5 Trading Tools (Part 25): Expanding to Multiple Distributions with Interactive Switching

MQL5 Trading Tools (Part 25): Expanding to Multiple Distributions with Interactive Switching

In this article, we expand the MQL5 graphing tool to support seventeen statistical distributions with interactive cycling via a header switch icon. We add type-specific data loading, discrete and continuous histogram computation, and theoretical density functions for each model, with dynamic titles, axis labels, and parameter panels that adapt automatically. The result lets you overlay distribution models on the same sample and compare fit across families without reloading the tool.
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Markets Positioning Codex in MQL5 (Part 2):  Bitwise Learning, with Multi-Patterns for Nvidia

Markets Positioning Codex in MQL5 (Part 2): Bitwise Learning, with Multi-Patterns for Nvidia

We continue our new series on Market-Positioning, where we study particular assets, with specific trade directions over manageable test windows. We started this by considering Nvidia Corp stock in the last article, where we covered 5 signal patterns from the complimentary pairing of the RSI and DeMarker oscillators. For this article, we cover the remaining 5 patterns and also delve into multi-pattern options that not only feature untethered combinations of all ten, but also specialized combinations of just a pair.
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Market Positioning Codex for VGT with Kendall's Tau and Distance Correlation

Market Positioning Codex for VGT with Kendall's Tau and Distance Correlation

In this article, we look to explore how a complimentary indicator pairing can be used to analyze the recent 5-year history of Vanguard Information Technology Index Fund ETF. By considering two options of algorithms, Kendall’s Tau and Distance-Correlation, we look to select not just an ideal indicator pair for trading the VGT, but also suitable signal-pattern pairings of these two indicators.
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From Novice to Expert: Animated News Headline Using MQL5 (V)—Event Reminder System

From Novice to Expert: Animated News Headline Using MQL5 (V)—Event Reminder System

In this discussion, we’ll explore additional advancements as we integrate refined event‑alerting logic for the economic calendar events displayed by the News Headline EA. This enhancement is critical—it ensures users receive timely notifications a short time before key upcoming events. Join this discussion to discover more.
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Feature Engineering for ML (Part 4): Implementing Time Features in MQL5

Feature Engineering for ML (Part 4): Implementing Time Features in MQL5

Applying Python session boundaries to MQL5 broker timestamps misclassifies session membership by two to three hours on any non-UTC broker, corrupting session flags across the full backtest history. We implement CTimeFeatures.mqh, containing CRingBuffer and CTimeFeatures, with three EA-facing methods: Initialize (UTC offset capture and frequency gate configuration), Update (log return push to session-conditional ring buffers), and Calculate (cyclical encoding, session flags, and session volatility). The output is a flat double array drop-compatible with Python's get_time_features for sub-hourly, hourly, and daily timeframes.
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Mastering Log Records (Part 2): Formatting Logs

Mastering Log Records (Part 2): Formatting Logs

In this article, we will explore how to create and apply log formatters in the library. We will see everything from the basic structure of a formatter to practical implementation examples. By the end, you will have the necessary knowledge to format logs within the library, and understand how everything works behind the scenes.
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The MQL5 Standard Library Explorer (Part 12): Multi-Timeframe Composite-Score Dashboard

The MQL5 Standard Library Explorer (Part 12): Multi-Timeframe Composite-Score Dashboard

The article implements CMultiTimeframeMatrix, a reusable dashboard that maps symbols vs. timeframes and displays a numeric, colour‑coded score. The score combines trend, momentum, and volatility, updates by timer, and respects performance constraints. You will learn how to build the UI with CAppDialog/CLabel, compute metrics via CMatrixDouble, and embed the component into a thin EA for a consistent, real-time overview.
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MQL5 Trading Tools (Part 27): Rendering Parametric Butterfly Curve on Canvas

MQL5 Trading Tools (Part 27): Rendering Parametric Butterfly Curve on Canvas

In this article, we explore the butterfly curve, a parametric mathematical equation, and render it visually on a MQL5 canvas. We build an interactive display with a draggable, resizable canvas window, supersampled curve rendering, gradient backgrounds, and a color-segmented legend. By the end, we have a fully functional visual tool that plots the butterfly curve directly on the MetaTrader 5 chart.
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Engineering Trading Discipline into Code (Part 7): Automating Equity Protection Through Governance Logic

Engineering Trading Discipline into Code (Part 7): Automating Equity Protection Through Governance Logic

Automated trading systems often focus heavily on signal generation while neglecting the mechanisms required to protect capital during periods of stress. This article presents an Equity Governance Framework in MQL5 that monitors drawdown conditions, evaluates equity pressure, and dynamically controls trading activity through a state-driven risk management model. By combining drawdown analysis, cooldown logic, trade authorization, and execution restrictions, the framework demonstrates how trading discipline can be engineered directly into code using a modular and extensible architecture.
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Reimagining Classic Strategies (Part VII) : Forex Markets And Sovereign Debt Analysis on the USDJPY

Reimagining Classic Strategies (Part VII) : Forex Markets And Sovereign Debt Analysis on the USDJPY

In today's article, we will analyze the relationship between future exchange rates and government bonds. Bonds are among the most popular forms of fixed income securities and will be the focus of our discussion.Join us as we explore whether we can improve a classic strategy using AI.
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Developing an MQTT client for Metatrader 5: a TDD approach — Part 5

Developing an MQTT client for Metatrader 5: a TDD approach — Part 5

This article is the fifth part of a series describing our development steps of a native MQL5 client for the MQTT 5.0 protocol. In this part we describe the structure of PUBLISH packets, how we are setting their Publish Flags, encoding Topic Name(s) strings, and setting Packet Identifier(s) when required.
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Stepwise feature selection in MQL5

Stepwise feature selection in MQL5

In this article, we introduce a modified version of stepwise feature selection, implemented in MQL5. This approach is based on the techniques outlined in Modern Data Mining Algorithms in C++ and CUDA C by Timothy Masters.
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File-Based Versioning of EA Parameters in MQL5

File-Based Versioning of EA Parameters in MQL5

This article explains how to implement parameter versioning in MQL5 using binary files and packed structures. It shows how to write and read fixed-size records with FileWriteStruct and FileReadStruct in FILE_BIN mode, including version numbers, timestamps, and a checksum. You will also see how to detect changes via checksums, append records safely, and load the latest configuration without overwriting prior settings.
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Data Science and ML (Part 48): Are Transformers a Big Deal for Trading?

Data Science and ML (Part 48): Are Transformers a Big Deal for Trading?

From ChatGPT to Gemini and many model AI tools for text, image, and video generation. Transformers have rocked the AI-world. But, are they applicable in the financial (trading) space? Let's find out.
All about Automated Trading Championship: Reporting the Championship 2006
All about Automated Trading Championship: Reporting the Championship 2006

All about Automated Trading Championship: Reporting the Championship 2006

This article contains Weekly Reports of the ATC 2006. These materials are like snapshots, they are interesting-to-read not only during the Championship, but years later as well.
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From Basic to Intermediate: Union (I)

From Basic to Intermediate: Union (I)

In this article we will look at what a union is. Here, through experiments, we will analyze the first constructions in which union can be used. However, what will be shown here is only a core part of a set of concepts and information that will be covered in subsequent articles. 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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Implementing Practical Modules from Other Languages in MQL5 (Part 05): The Logging module from Python, Log Like a Pro

Implementing Practical Modules from Other Languages in MQL5 (Part 05): The Logging module from Python, Log Like a Pro

Integrating Python's logging module with MQL5 empowers traders with a systematic logging approach, simplifying the process of monitoring, debugging, and documenting trading activities. This article explains the adaptation process, offering traders a powerful tool for maintaining clarity and organization in trading software development.
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Building a Trade Analytics System (Part 2): How to Capture Closed Trades and Send JSON in MQL5

Building a Trade Analytics System (Part 2): How to Capture Closed Trades and Send JSON in MQL5

We build a lightweight bridge that captures closed trades in MetaTrader 5 and sends them to an external backend over HTTP as JSON. It uses OnTradeTransaction for event detection, reads details from deal history, assembles a JSON payload, and posts it via WebRequest. A local Flask API is used to test the flow, delivering a working path to move trade data outside the terminal.
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Developing a Replay System (Part 39): Paving the Path (III)

Developing a Replay System (Part 39): Paving the Path (III)

Before we proceed to the second stage of development, we need to revise some ideas. Do you know how to make MQL5 do what you need? Have you ever tried to go beyond what is contained in the documentation? If not, then get ready. Because we will be doing something that most people don't normally do.
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Graph Theory: Traversal Breadth-First Search (BFS) Applied in Trading

Graph Theory: Traversal Breadth-First Search (BFS) Applied in Trading

Breadth First Search (BFS) uses level-order traversal to model market structure as a directed graph of price swings evolving through time. By analyzing historical bars or sessions layer by layer, BFS prioritizes recent price behavior while still respecting deeper market memory.
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Introduction to MQL5 (Part 39): Beginner Guide to File Handling in MQL5 (I)

Introduction to MQL5 (Part 39): Beginner Guide to File Handling in MQL5 (I)

This article introduces file handling in MQL5 using a practical, project-based workflow. You will use FileSelectDialog to choose or create a CSV file, open it with FileOpen, and write structured account headers such as account name, balance, login, date range, and last update. The result is a clear foundation for a reusable trading journal and safe file operations in MetaTrader 5.
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Developing a Replay System (Part 41): Starting the second phase (II)

Developing a Replay System (Part 41): Starting the second phase (II)

If everything seemed right to you up to this point, it means you're not really thinking about the long term, when you start developing applications. Over time you will no longer need to program new applications, you will just have to make them work together. So let's see how to finish assembling the mouse indicator.
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Developing a Replay System (Part 34): Order System (III)

Developing a Replay System (Part 34): Order System (III)

In this article, we will complete the first phase of construction. Although this part is fairly quick to complete, I will cover details that were not discussed previously. I will explain some points that many do not understand. Do you know why you have to press the Shift or Ctrl key?
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From Basic to Intermediate: Events (II)

From Basic to Intermediate: Events (II)

In this article, we will see that not everything always needs to be implemented in a certain specific way. There are alternative approaches to problem-solving. To properly understand this article, it is necessary to grasp the concepts described in the previous articles. The materials presented here are for educational purposes only. Do not regard it as a finished application. Its purpose is to study the concepts presented here.
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Biogeography-Based Optimization (BBO)

Biogeography-Based Optimization (BBO)

Biogeography-Based Optimization (BBO) is an elegant global optimization method inspired by natural processes of species migration between islands within archipelagos. The algorithm is based on a simple yet powerful idea: high-quality solutions actively share their characteristics, while low-quality ones actively adopt new features, creating a natural flow of information from the best solutions to the worst. A unique adaptive mutation operator provides an excellent balance between exploration and exploitation. BBO demonstrates high efficiency on a variety of tasks.
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Analyzing Price Time Gaps in MQL5 (Part II): Creating a Heat Map of Liquidity Distribution Over Time

Analyzing Price Time Gaps in MQL5 (Part II): Creating a Heat Map of Liquidity Distribution Over Time

A detailed guide on how to create a heat map indicator for MetaTrader 5 that visualizes the price distribution over time. The article reveals the mathematical basis of time density analysis, where each price level is colored from red (minimum stay time) to blue (maximum stay time).