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 56): Adapting the Modules

Developing a Replay System (Part 56): Adapting the Modules

Although the modules already interact with each other properly, an error occurs when trying to use the mouse pointer in the replay service. We need to fix this before moving on to the next step. Additionally, we will fix an issue in the mouse indicator code. So this version will be finally stable and properly polished.
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Mastering Log Records (Part 5): Optimizing the Handler with Cache and Rotation

Mastering Log Records (Part 5): Optimizing the Handler with Cache and Rotation

This article improves the logging library by adding formatters in handlers, the CIntervalWatcher class to manage execution cycles, optimization with caching and file rotation, performance tests and practical examples. With these improvements, we ensure an efficient, scalable and adaptable logging system to different development scenarios.
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Gaussian Processes in Machine Learning (Part 1): Classification Model in MQL5

Gaussian Processes in Machine Learning (Part 1): Classification Model in MQL5

The article considers the classification model of Gaussian processes. We will start by studying its theoretical principles moving on to the practical development of the GP library in MQL5.
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Dingo Optimization Algorithm (DOA)

Dingo Optimization Algorithm (DOA)

The article presents a new metaheuristic method based on the hunting strategies of Australian dingoes: group attack, chase, and scavenging. Let's see how the Dingo Optimization Algorithm (DOA) performs algorithmically.
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MQL5 Wizard Techniques you should know (Part 92): Using B-Tree Indexing and a Bayesian NN in a Custom Signal Class

MQL5 Wizard Techniques you should know (Part 92): Using B-Tree Indexing and a Bayesian NN in a Custom Signal Class

In this article we present yet another custom MQL5 Signal Class that we are labelling ‘CSignalBTreeBayesian’. We are marrying the algorithm of a balanced tree with a neural network that is built on Bayesian principles to formulate yet another custom signal testable independently or with other signals thanks to the MQL5 Wizard.
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Overcoming Accessibility Problems in MQL5 Trading Tools (Part I): How to Add Contextual Voice Alerts in MQL5 Indicators

Overcoming Accessibility Problems in MQL5 Trading Tools (Part I): How to Add Contextual Voice Alerts in MQL5 Indicators

This article explores an accessibility-focused enhancement that goes beyond default terminal alerts by leveraging MQL5 resource management to deliver contextual voice feedback. Instead of generic tones, the indicator communicates what has occurred and why, allowing traders to understand market events without relying solely on visual observation. This approach is especially valuable for visually impaired traders, but it also benefits busy or multitasking users who prefer hands-free interaction.
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Forecasting a Conditional Distribution Using MLP

Forecasting a Conditional Distribution Using MLP

In this article, we will consider an MLP-based regression model that predicts not only the conditional expectation but also the conditional variance. In other words, we will train our network to predict the entire distribution of future prices based on the input feature vector. But for this purpose we will have to implement our own loss function.
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Introduction to MQL5 (Part 37): Mastering API and WebRequest Function in MQL5 (XI)

Introduction to MQL5 (Part 37): Mastering API and WebRequest Function in MQL5 (XI)

In this article, we show how to send authenticated requests to the Binance API using MQL5 to retrieve your account balance for all assets. Learn how to use your API key, server time, and signature to securely access account data, and how to save the response to a file for future use.
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Body in Connexus (Part 4): Adding HTTP body support

Body in Connexus (Part 4): Adding HTTP body support

In this article, we explored the concept of body in HTTP requests, which is essential for sending data such as JSON and plain text. We discussed and explained how to use it correctly with the appropriate headers. We also introduced the ChttpBody class, part of the Connexus library, which will simplify working with the body of requests.
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Market Simulation (Part 24): Position View (II)

Market Simulation (Part 24): Position View (II)

In this article, I will show how to use an indicator to track open positions on the trading server in the simplest and most practical way possible. I am doing this step by step to show that you do not necessarily have to move all of this into an Expert Advisor. Many of you have probably become used to doing that for one reason or another. In fact, that is not really justified, because as this implementation evolves, it will become clear that you can create or implement different types of indicators for this purpose.
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Strategy Configuration via External JSON Files in MQL5: Replacing Input Parameters with a Runtime Config Loader

Strategy Configuration via External JSON Files in MQL5: Replacing Input Parameters with a Runtime Config Loader

The article presents CJsonConfigLoader and a typed SStrategyConfig that move EA inputs to a shared JSON file. A hand-written, quote-aware tokenizer parses a flat object without any DLLs. A hotkey triggers reload so all instances can pick up new lot size, SL/TP, and spread limits without reattaching the EA. On malformed input, the loader falls back to safe defaults and keeps the previous configuration.
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Developing an MQTT client for Metatrader 5: a TDD approach — Part 6

Developing an MQTT client for Metatrader 5: a TDD approach — Part 6

This article is the sixth part of a series describing our development steps of a native MQL5 client for the MQTT 5.0 protocol. In this part we comment on the main changes in our first refactoring, how we arrived at a viable blueprint for our packet-building classes, how we are building PUBLISH and PUBACK packets, and the semantics behind the PUBACK Reason Codes.
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Connexus Observer (Part 8): Adding a Request Observer

Connexus Observer (Part 8): Adding a Request Observer

In this final installment of our Connexus library series, we explored the implementation of the Observer pattern, as well as essential refactorings to file paths and method names. This series covered the entire development of Connexus, designed to simplify HTTP communication in complex applications.
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Implementation of the Quantum Reservoir Computing (QRC) circuit

Implementation of the Quantum Reservoir Computing (QRC) circuit

A revolutionary approach to machine learning in trading through quantum computing. The article demonstrates a practical implementation of an adaptive QRC system with continuous retraining for predicting market movements in real time.
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Creating an Interactive Portfolio Analyzer Dashboard with CCanvas in MQL5

Creating an Interactive Portfolio Analyzer Dashboard with CCanvas in MQL5

This article presents a standalone Portfolio Analyzer dashboard implemented as an Expert Advisor for MetaTrader 5. It reads account deal history, reconstructs closed positions, and attributes results by magic number or normalized comment to deliver clear per-strategy metrics. The interface provides a vector equity curve, date filters, and strategy selectors, plus a Pearson correlation matrix to reveal strategy redundancy. You can attach it to a separate chart without modifying existing trading EAs.
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MQL5 Trading Tools (Part 34): Replacing Native Chart Objects with an Interactive Canvas Drawing Layer

MQL5 Trading Tools (Part 34): Replacing Native Chart Objects with an Interactive Canvas Drawing Layer

We replace native MetaTrader chart objects with a canvas-based drawing engine that renders tools pixel-by-pixel on a full-chart bitmap layer. The article implements persistent object storage with per-tool style memory, precise hit testing, selection, whole-object dragging, and handle manipulation. It also adds new line tools, a reorganized category system with a one-click delete action, and a rubber-band preview for multi-click placement.
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Introduction to MQL5 (Part 40): Beginner Guide to File Handling in MQL5 (II)

Introduction to MQL5 (Part 40): Beginner Guide to File Handling in MQL5 (II)

Create a CSV trading journal in MQL5 by reading account history over a defined period and writing structured records to file. The article explains deal counting, ticket retrieval, symbol and order type decoding, and capturing entry (lot, time, price, SL/TP) and exit (time, price, profit, result) data with dynamic arrays. The result is an organized, persistent log suitable for analysis and reporting.
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Modular Indicator Architecture in MQL5 (Part 1): Stop Copy-Pasting and Start Writing Scalable, Reusable Code

Modular Indicator Architecture in MQL5 (Part 1): Stop Copy-Pasting and Start Writing Scalable, Reusable Code

This article develops an object-oriented framework for MQL5 indicators by evolving a primitive example into reusable modules. It formalizes partial buffer recalculation in OnCalculate, moves logic into header-based classes (CAppliedPrice, CSma), and introduces CSubIndiBase, CIndicatorBase, and a registry to centralize requirements. You get portable components, isolated inputs, and clean buffers with minimal boilerplate, making new indicators faster to assemble and easier to maintain.
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Execution Cost and Slippage Sensitivity Analyzer

Execution Cost and Slippage Sensitivity Analyzer

Backtests often understate spread, commission, and slippage. This MQL5 analyzer loads closing deals and simulates rising execution costs to measure robustness. It computes the breakeven cost per deal, the cushion over an assumed cost, the net profit and profit factor at that cost, and how many winners turn into losers, then summarizes the result with an A+ to F grade and targeted guidance.
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Duelist Algorithm

Duelist Algorithm

What if your trading strategies could learn from each other, like real fighters? Duelist Algorithm is a new optimization method where trading system parameters literally duel for the right to be called the best.
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Beyond GARCH (Part I): Mandelbrot's MMAR versus Engle's GARCH

Beyond GARCH (Part I): Mandelbrot's MMAR versus Engle's GARCH

This article starts the MMAR pipeline on EURUSD M5 data. We load market data via the MetaTrader5 Python API and run partition-function analysis with non-overlapping intervals to test for multifractal scaling. The result is an evidence-based decision on fractality, a prerequisite for building MMAR and for choosing whether to proceed beyond GARCH.
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Feature Engineering for ML (Part 6): Microstructural Features in MQL5

Feature Engineering for ML (Part 6): Microstructural Features in MQL5

The article introduces CMicrostructureFeatures, an MQL5 class for bar‑level microstructure features: Roll spread/impact, Corwin‑Schultz spread and sigma, Kyle's Lambda, Amihud's ILLIQ, and Hasbrouck's Lambda. Calculations rely solely on OHLCV using rolling windows. It clarifies the implications of MT5 tick volume for lambda estimators and keeps spread estimators volume‑independent. A validation script asserts sizing and basic bounds on outputs.
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The View and Controller components for tables in the MQL5 MVC paradigm: Containers

The View and Controller components for tables in the MQL5 MVC paradigm: Containers

In this article, we will discuss creating a "Container" control that supports scrolling its contents. Within the process, the already implemented classes of graphics library controls will be improved.
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Developing a Replay System (Part 63): Playing the service (IV)

Developing a Replay System (Part 63): Playing the service (IV)

In this article, we will finally solve the problems with the simulation of ticks on a one-minute bar so that they can coexist with real ticks. This will help us avoid problems in the future. The material presented here is 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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From Basic to Intermediate: Struct (VII)

From Basic to Intermediate: Struct (VII)

In today's article, we will show how to approach solving problems related to structuring different elements and creating simpler and more attractive solutions. Although the content is oriented toward learning and, therefore, does not constitute production code, it is essential to thoroughly understand the concepts and knowledge that will be covered here. In this way, in the future we will be able to follow the codes we will present.
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MQL5 Wizard Techniques you should know (Part 93): Using Suffix Automation and an Auto Encoder in a Custom Money Management Class

MQL5 Wizard Techniques you should know (Part 93): Using Suffix Automation and an Auto Encoder in a Custom Money Management Class

For this article we switch to a custom MQL5 Wizard class implementation that explores Money Management. We are labelling our custom class ‘CMoneySuffixAE’ that we derive by combining the Suffix Automaton algorithm with an Autoencoder neural network. As always, this formulation is testable with MQL5 Wizard Assembled Expert Advisors that can be tuned with various entry signals and trailing stop approaches.
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Feature Engineering for ML (Part 5): Microstructural Features in Python

Feature Engineering for ML (Part 5): Microstructural Features in Python

This article implements the Chapter 19 microstructure suite in afml.features.microstructure and explains a two-layer design for OHLCV-only and tick-augmented workflows. We cover Roll and Corwin–Schultz spread/volatility, Kyle's, Amihud's, and Hasbrouck's lambdas, VPIN, and bar‑level imbalance features, all in Numba‑accelerated kernels. A single np.searchsorted pass resolves bar boundaries, enabling prange parallelization and producing a bar‑indexed feature matrix ready for downstream ML models.
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Developing a Manual Backtesting Expert Advisor: Additional Features

Developing a Manual Backtesting Expert Advisor: Additional Features

We enhance the manual backtesting EA with real-time lot adjustment, an order module for buy/sell stops and limits, and a Trade Manager to modify TP/SL and close positions individually. The article explains control setup with CButton/CBmpButton/CEdit, logic in OnTick, and workarounds for Strategy Tester input constraints. Readers can reuse these components to speed up testing workflows and implement robust trade management.
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Custom Debugging and Profiling Tools for MQL5 Development (Part III): Regression Gates for Performance and Trading Rules

Custom Debugging and Profiling Tools for MQL5 Development (Part III): Regression Gates for Performance and Trading Rules

This article adds a regression gate to the MQL5 debugging and profiling workflow. It keeps the Part II profiler, TestLite runner, and trading math helper as contracts, then compares current profiler evidence with an accepted baseline. The workflow also adds symbol-aware assertions, compact status files, and report tables so performance drift, missing tests, and broker-assumption problems are visible before a build is accepted.
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MQL5 Wizard Techniques you should know (Part 30): Spotlight on Batch-Normalization in Machine Learning

MQL5 Wizard Techniques you should know (Part 30): Spotlight on Batch-Normalization in Machine Learning

Batch normalization is the pre-processing of data before it is fed into a machine learning algorithm, like a neural network. This is always done while being mindful of the type of Activation to be used by the algorithm. We therefore explore the different approaches that one can take in reaping the benefits of this, with the help of a wizard assembled Expert Advisor.
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How To Profile MQL5 Code in MetaEditor

How To Profile MQL5 Code in MetaEditor

This article profiles a rolling z-score indicator with bands using MetaEditor's built-in sampling profiler. We read the Total CPU and Self CPU columns and follow the heat‑mapped source to the true hotspots, replace window rescans with sliding accumulators, remove a redundant array copy, and honor prev_calculated. The result is the same output with measured samples reduced from roughly 7,050 to 59.
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Introduction to MQL5 (Part 34): Mastering API and WebRequest Function in MQL5 (VIII)

Introduction to MQL5 (Part 34): Mastering API and WebRequest Function in MQL5 (VIII)

In this article, you will learn how to create an interactive control panel in MetaTrader 5. We cover the basics of adding input fields, action buttons, and labels to display text. Using a project-based approach, you will see how to set up a panel where users can type messages and eventually display server responses from an API.
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MQL5 Bootstrap (II): Essential Validators for Robust Trading Systems

MQL5 Bootstrap (II): Essential Validators for Robust Trading Systems

The article builds a reusable validation layer for Expert Advisors in MQL5. It implements lot-size rules and normalization, SL/TP and freeze-level guards, price digit normalization, margin sufficiency checks, unchanged-level filtering on modifications, account order-limit control, new-bar detection, symbol tradability checks, economic-calendar news windows, and session detectors. The result is cleaner code and fewer terminal errors in live trading.
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Bison Algorithm (BIA)

Bison Algorithm (BIA)

A new optimization method, the Bison Algorithm (BIA), uses two strategies, inspired by the behavior of bison, for solving continuous problems with a single objective function. The key features of BIA are two fundamental principles borrowed from the behavior of bison: the ability to move dynamically and a defensive strategy.
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Beyond the Clock (Part 3): Building an Indicator Window for Alternative Bars in MQL5

Beyond the Clock (Part 3): Building an Indicator Window for Alternative Bars in MQL5

AlternativeBarsViewer is a subwindow indicator that renders all ten alternative bar types as color‑coded candles using the same CBarConstructor hierarchy as BarBuilderEA, ensuring identical bars. It supports three data sources (real ticks, synthetic OHLC ticks, or the EA's CSV) and two render modes (TIME and INDEX) toggleable at runtime. Degenerate bars are highlighted and summarized on a compact panel, enabling live calibration without leaving the terminal.
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Developing a Replay System (Part 58): Returning to Work on the Service

Developing a Replay System (Part 58): Returning to Work on the Service

After a break in development and improvement of the service used for replay/simulator, we are resuming work on it. Now that we've abandoned the use of resources like terminal globals, we'll have to completely restructure some parts of it. Don't worry, this process will be explained in detail so that everyone can follow the development of our service.
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Market Simulation: (Part 11): Sockets (V)

Market Simulation: (Part 11): Sockets (V)

We are beginning to implement the connection between Excel and MetaTrader 5, but first we need to understand some key points. This way, you won't have to rack your brains trying to figure out why something works or doesn't. And before you frown at the prospect of integrating Python and Excel, let's see how we can (to some extent) control MetaTrader 5 through Excel using xlwings. What we demonstrate here will primarily focus on educational objectives. However, don't think that we can only do what will be covered here.
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From Basic to Intermediate: Indicator (III)

From Basic to Intermediate: Indicator (III)

In this article, we will explore how to declare various graphical representation indicators, such as DRAW_COLOR_LINE and DRAW_FILLING. Additionally, of course, we will learn how to plot graphs using multiple indicators in a simple, practical, and fast way. This can truly change your perspective on MetaTrader 5 and the market as a whole.
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Code, Tears, and Algo Forge

Code, Tears, and Algo Forge

This article discusses the transition to MQL5 Algo Forge as a modern and convenient format for publishing program code and article attachments. Using repositories instead of traditional ZIP archives and source code allows you to keep projects up-to-date, make edits quickly, and professionally interact with your readers. Recommendations are provided for quickly migrating developments to the cloud environment via the MetaEditor interface.
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Market Microstructure in MQL5 (Part 4): Volatility That Remembers

Market Microstructure in MQL5 (Part 4): Volatility That Remembers

This article adds eight volatility functions to MicroStructure_Foundation.mqh, including realized volatility, duration-adjusted volatility, fractional volatility, a FIGARCH-inspired proxy, a volatility clustering index, a GJR-GARCH asymmetry measure (using the Dube library), bipower-variation jump detection, and a wrapper function. The MFDFA implementation is revised to return the conventional Legendre-transform Δα with an R² confidence field, replacing the τ-spread proxy used in the original submission. Thresholds are derived from 514 NY sessions of NQ E-mini Nasdaq 100 futures (May 2024–May 2026); no new include file is created.