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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Mastering Log Records (Part 10): Avoiding Log Replay by Implementing a Suppression

Mastering Log Records (Part 10): Avoiding Log Replay by Implementing a Suppression

We created a log suppression system in the Logify library. It details how the CLogifySuppression class reduces console noise by applying configurable rules to avoid repetitive or irrelevant messages. We also cover the external configuration framework, validation mechanisms, and comprehensive testing to ensure robustness and flexibility in log capture during bot or indicator development.
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Feature Engineering for ML (Part 1): Fractional Differentiation — Stationarity Without Memory Loss

Feature Engineering for ML (Part 1): Fractional Differentiation — Stationarity Without Memory Loss

Integer differentiation forces a binary choice between stationarity and memory: returns (d=1) are stationary but discard all price-level information; raw prices (d=0) preserve memory but violate ML stationarity assumptions. We implement the fixed-width fractional differentiation (FFD) method from AFML Chapter 5, covering get_weights_ffd (iterative recurrence with threshold cutoff), frac_diff_ffd (bounded dot product per bar), and fracdiff_optimal (binary search for minimum stationary d*).
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Atmosphere Clouds Model Optimization (ACMO): Practice

Atmosphere Clouds Model Optimization (ACMO): Practice

In this article, we will continue diving into the implementation of the ACMO (Atmospheric Cloud Model Optimization) algorithm. In particular, we will discuss two key aspects: the movement of clouds into low-pressure regions and the rain simulation, including the initialization of droplets and their distribution among clouds. We will also look at other methods that play an important role in managing the state of clouds and ensuring their interaction with the environment.
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Larry Williams Market Secrets (Part 7): An Empirical Study of the Trade Day of the Week Concept

Larry Williams Market Secrets (Part 7): An Empirical Study of the Trade Day of the Week Concept

An empirical study of Larry Williams’ Trade Day of the Week concept, showing how time-based market bias can be measured, tested, and applied using MQL5. This article presents a practical framework for analyzing win rates and performance across trading days to improve short-term trading systems.
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From Basic to Intermediate: Struct (IV)

From Basic to Intermediate: Struct (IV)

In this article, we will explore how to create so-called structural code, where the entire context and methods for manipulating variables and information are placed within a structure to create a suitable context for implementing any code. Therefore, we will examine the necessity of using a private section of the code to separate what is public from what is not, thereby adhering to the rule of encapsulation and preserving the context for which the data structure was created.
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Introduction to MQL5 (Part 35): Mastering API and WebRequest Function in MQL5 (IX)

Introduction to MQL5 (Part 35): Mastering API and WebRequest Function in MQL5 (IX)

Discover how to detect user actions in MetaTrader 5, send requests to an AI API, extract responses, and implement scrolling text in your panel.
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Population optimization algorithms: Bacterial Foraging Optimization - Genetic Algorithm (BFO-GA)

Population optimization algorithms: Bacterial Foraging Optimization - Genetic Algorithm (BFO-GA)

The article presents a new approach to solving optimization problems by combining ideas from bacterial foraging optimization (BFO) algorithms and techniques used in the genetic algorithm (GA) into a hybrid BFO-GA algorithm. It uses bacterial swarming to globally search for an optimal solution and genetic operators to refine local optima. Unlike the original BFO, bacteria can now mutate and inherit genes.
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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.
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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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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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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Introduction to MQL5 (Part 41): Beginner Guide to File Handling in MQL5 (III)

Introduction to MQL5 (Part 41): Beginner Guide to File Handling in MQL5 (III)

Learn how to read a CSV file in MQL5 and organize its trading data into dynamic arrays. This article shows step by step how to count file elements, store all data in a single array, and separate each column into dedicated arrays, laying the foundation for advanced analysis and trading performance visualization.
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From Basic to Intermediate: Struct (VI)

From Basic to Intermediate: Struct (VI)

In this article, we will explore how to approach the implementation of a common structural code base. The goal is to reduce the programming workload and leverage the full potential of the programming language itself—in this case, MQL5.
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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 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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Statistical Arbitrage Through Cointegrated Stocks (Part 10): Detecting Structural Breaks

Statistical Arbitrage Through Cointegrated Stocks (Part 10): Detecting Structural Breaks

This article presents the Chow test for detecting structural breaks in pair relationships and the application of the Cumulative Sum of Squares - CUSUM - for structural breaks monitoring and early detection. The article uses the Nvidia/Intel partnership announcement and the US Gov foreign trade tariff announcement as examples of slope inversion and intercept shift, respectively. Python scripts for all the tests are provided.
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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Introduction to MQL5 (Part 43): Beginner Guide to File Handling in MQL5 (V)

Introduction to MQL5 (Part 43): Beginner Guide to File Handling in MQL5 (V)

The article explains how to use MQL5 structures with binary files to persist Expert Advisor parameters. It covers defining structures, accessing members, and distinguishing simple from complex layouts, then writing and reading entire records using FileWriteStruct and FileReadStruct in FILE BIN mode. You will learn safe patterns for fixed-size data and how shared storage (FILE COMMON) enables reuse across sessions and terminals.
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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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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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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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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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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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Using the MQL5 Economic Calendar for News Filter (Part 4): Accurate Backtesting with Static Data

Using the MQL5 Economic Calendar for News Filter (Part 4): Accurate Backtesting with Static Data

This article implements a static, CSV-based news source for the Strategy Tester, so historical economic news events can be preloaded and queried during backtesting. It replaces live calendar calls in tester mode with a fast in-memory search, preserves the live logic for trading, and delivers deterministic, repeatable results with explicit control over included events, enabling reliable validation of news-aware filters, stop suspension, and trade-blocking rules.
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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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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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MetaTrader 5 Machine Learning Blueprint (Part 14): Transaction Cost Modeling for Triple-Barrier Labels in MQL5

MetaTrader 5 Machine Learning Blueprint (Part 14): Transaction Cost Modeling for Triple-Barrier Labels in MQL5

The article replaces hardcoded cost assumptions in triple-barrier labeling with measured inputs. An MQL5 script captures spread distribution, swap rates, and symbol metadata from your broker, and a Python model converts them into a broker-calibrated min ret you can pass to get events. Labels then reflect the actual round-trip friction for your instrument and holding period.
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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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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 6): Optimizing a generated Expert Advisor

The MQL5 Standard Library Explorer (Part 6): Optimizing a generated Expert Advisor

In this discussion, we follow up on the previously developed multi-signal Expert Advisor with the objective of exploring and applying available optimization methods. The aim is to determine whether the trading performance of the EA can be meaningfully improved through systematic optimization based on historical data.
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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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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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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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MQL5 Trading Tools (Part 15): Canvas Blur Effects, Shadow Rendering, and Smooth Mouse Wheel Scrolling

MQL5 Trading Tools (Part 15): Canvas Blur Effects, Shadow Rendering, and Smooth Mouse Wheel Scrolling

In this article, we enhance the MQL5 canvas dashboard with advanced visual effects, including blur gradients for fog overlays, shadow rendering for headers, and antialiased drawing for smoother lines and curves. We add smooth mouse wheel scrolling to the text panel that does not interfere with the chart zoom scale, technically an upgrade.
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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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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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Header in the Connexus (Part 3): Mastering the Use of HTTP Headers for Requests

Header in the Connexus (Part 3): Mastering the Use of HTTP Headers for Requests

We continue developing the Connexus library. In this chapter, we explore the concept of headers in the HTTP protocol, explaining what they are, what they are for, and how to use them in requests. We cover the main headers used in communications with APIs, and show practical examples of how to configure them in the library.
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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.