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 30): Expert Advisor project — C_Mouse class (IV)

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

Today we will learn a technique that can help us a lot in different stages of our professional life as a programmer. Often it is not the platform itself that is limited, but the knowledge of the person who talks about the limitations. This article will tell you that with common sense and creativity you can make the MetaTrader 5 platform much more interesting and versatile without resorting to creating crazy programs or anything like that, and create simple yet safe and reliable code. We will use our creativity to modify existing code without deleting or adding a single line to the source code.
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Reimagining Classic Strategies (Part 22): Ensemble Mean Reverting Strategy

Reimagining Classic Strategies (Part 22): Ensemble Mean Reverting Strategy

This article will illustrate to the reader how to implement a mean-reverting strategy for the EURUSD pair. The strategy follows contrarian trading rules. Our strategy implements a weekly moving average channel, with one moving average on the high-price feed and the latter on the low-price feed. We enter short positions when the price falls beneath the low moving average and long positions when the price rises above the high moving average. Additionally, we will export daily market data to build a simple ONNX model of the market to provide an additional filter for our entries. This provides the reader with a reproducible template for strategy development and backtesting.
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Neural Networks in Trading: LSTM Optimization for Multivariate Time Series Forecasting (DA-CG-LSTM)

Neural Networks in Trading: LSTM Optimization for Multivariate Time Series Forecasting (DA-CG-LSTM)

This article introduces the DA-CG-LSTM algorithm, which offers new approaches to time series analysis and forecasting. It explains how innovative attention mechanisms and model flexibility can improve forecast accuracy.
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Developing a Terminal Manager (Part 2): Running Multiple Terminal Instances

Developing a Terminal Manager (Part 2): Running Multiple Terminal Instances

Let's move on to using multiple terminal instances on the server by setting up a simple control panel for starting and stopping them. Now it is time to expand the functionality and move on to the next stages — implementing more complex features, such as managing multiple terminal instances, state persistence, integration with the MetaTrader 5 API, and a web interface with comprehensive information about the terminals.
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Table and Header Classes based on a table model in MQL5: Applying the MVC concept

Table and Header Classes based on a table model in MQL5: Applying the MVC concept

This is the second part of the article devoted to the implementation of the table model in MQL5 using the MVC (Model-View-Controller) architectural paradigm. The article discusses the development of table classes and the table header based on a previously created table model. The developed classes will form the basis for further implementation of View and Controller components, which will be discussed in the following articles.
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Covariance Matrix Adaptation Evolution Strategy (CMA-ES)

Covariance Matrix Adaptation Evolution Strategy (CMA-ES)

The article explores one of the most interesting non-gradient optimization algorithms, which learns to understand the geometry of the objective function. We will focus on the classical implementation of CMA-ES with a slight modification - replacing the normal distribution with the power one. We will thoroughly examine the math behind the algorithm, as well as practical implementation, and check where CMA-ES is unbeatable and where it should be avoided.
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Evaluating the Quality of Forex Spread Trading Based on Seasonal Factors in MetaTrader 5

Evaluating the Quality of Forex Spread Trading Based on Seasonal Factors in MetaTrader 5

The article examines the quality of a seasonal trading approach on a daily timeframe, both for individual symbols and for spreads. Particular attention is paid to identifying recurring monthly cycles and the possibilities of their application in trading within the current year.
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Overcoming The Limitation of Machine Learning (Part 8): Nonparametric Strategy Selection

Overcoming The Limitation of Machine Learning (Part 8): Nonparametric Strategy Selection

This article shows how to configure a black-box model to automatically uncover strong trading strategies using a data-driven approach. By using Mutual Information to prioritize the most learnable signals, we can build smarter and more adaptive models that outperform conventional methods. Readers will also learn to avoid common pitfalls like overreliance on surface-level metrics, and instead develop strategies rooted in meaningful statistical insight.
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From Novice to Expert: Candlestick Momentum Confirmation for Classic Crossover Strategies

From Novice to Expert: Candlestick Momentum Confirmation for Classic Crossover Strategies

In this article, we refine a moving average crossover strategy with a momentum candle filter and an immediate retracement bar confirmation. When both conditions are met, a pending stop order is placed using a pivot-based stop loss and a 2R take profit. The complete MQL5 Expert Advisor code, finite-state-machine logic, and chart annotations are detailed.
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Reimagining Classic Strategies (Part VIII): Currency Markets And Precious Metals on the USDCAD

Reimagining Classic Strategies (Part VIII): Currency Markets And Precious Metals on the USDCAD

In this series of articles, we revisit well-known trading strategies to see if we can improve them using AI. In today's discussion, join us as we test whether there is a reliable relationship between precious metals and currencies.
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Measuring broker execution quality in MQL5: Why your live account doesn't match the backtest

Measuring broker execution quality in MQL5: Why your live account doesn't match the backtest

Live performance often drifts from backtests because of execution friction. We introduce an MQL5 diagnostic EA that records entry and exit slippage, asymmetry, observed spread, requotes, and per-leg latency, using a precise probe mode and an approximate passive mode, and writes every sample to CSV. Use the results to distinguish strategy issues from execution effects across your terminal, network, broker, and liquidity.
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Client in Connexus (Part 7): Adding the Client Layer

Client in Connexus (Part 7): Adding the Client Layer

In this article we continue the development of the connexus library. In this chapter we build the CHttpClient class responsible for sending a request and receiving an order. We also cover the concept of mocks, leaving the library decoupled from the WebRequest function, which allows greater flexibility for users.
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RiskGate: Centralized Risk Management for Multiple EAs

RiskGate: Centralized Risk Management for Multiple EAs

Many MetaTrader 5 setups run several EAs on one account, so risk gets fragmented and correlated exposure slips through. The article introduces RiskGate, a centralized Service that evaluates EA intents account‑wide: EAs send a JSON signal, the Service returns approved, lot and reason. You will see the client/server wiring, example rules (daily loss, exposure and correlation caps), unit‑tested handler design, and an EA example. The result is consistent portfolio‑level risk with simpler EAs.
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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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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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Mastering Log Records (Part 9): Implementing the builder pattern and adding default configurations

Mastering Log Records (Part 9): Implementing the builder pattern and adding default configurations

This article shows how to drastically simplify the use of the Logify library with the Builder pattern and automatic default configurations. It explains the structure of the specialized builders, how to use them with smart auto-completion, and how to ensure a functional log even without manual configuration. It also covers tweaks for MetaTrader 5 build 5100.
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Building a Hierarchical Market Structure Framework (Prototype) in MQL5 Using Modular Architecture and Event-Driven Design

Building a Hierarchical Market Structure Framework (Prototype) in MQL5 Using Modular Architecture and Event-Driven Design

This article describes a prototype reusable market structure framework for MQL5, built with a clean modular architecture and an internal event queue. It shows how to detect swing points, classify break-of-structure and change-of-character events, maintain a deterministic market state, and persist data to CSV. The focus is entirely on software engineering, component separation, and extensibility, not on trading signals. The prototype is a foundation for further development, not a production-ready library.
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Measuring What Matters (Part 3): The Reconstruction Engine — Validating Risk Footprints with Matrix Algebra

Measuring What Matters (Part 3): The Reconstruction Engine — Validating Risk Footprints with Matrix Algebra

This article performs a numerical verification of MQL5 eigendecomposition for a covariance matrix using the spectral theorem A = V Λ Vᵀ. It reconstructs the matrix with Diag(), Transpose(), and MatMul(), computes the residual and its Frobenius norm, and shows that deviations remain at floating‑point precision, with results printed to the Experts journal.
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From Basic to Intermediate: Objects (II)

From Basic to Intermediate: Objects (II)

In today's article, we will look at how to control some object properties in a simple way using code. We will also see how a custom application can place more than one object on the same chart. In addition, we will begin to understand the importance of assigning a short name to any indicator we plan to implement.
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Neural Networks in Trading: Actor—Director—Critic (Final Part)

Neural Networks in Trading: Actor—Director—Critic (Final Part)

The Actor–Director–Critic framework is an evolution of the classic agent learning architecture. The article presents practical experience of its implementation and adaptation to financial market conditions.
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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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MQL5 Wizard Techniques you should know (Part 23): CNNs

MQL5 Wizard Techniques you should know (Part 23): CNNs

Convolutional Neural Networks are another machine learning algorithm that tend to specialize in decomposing multi-dimensioned data sets into key constituent parts. We look at how this is typically achieved and explore a possible application for traders in another MQL5 wizard signal class.
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Backtracking Search Algorithm (BSA)

Backtracking Search Algorithm (BSA)

What if an optimization algorithm could remember its past journeys and use that memory to find better solutions? BSA does just that – balancing exploration with revisiting the tried and true. In this article, we reveal the secrets of the algorithm. A simple idea, minimum parameters and a stable result.
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Automating Trading Strategies in MQL5 (Part 51): The Bread and Butter Judas Swing Model with Premium and Discount

Automating Trading Strategies in MQL5 (Part 51): The Bread and Butter Judas Swing Model with Premium and Discount

We build a session-based reversal program in MQL5 using the Bread and Butter Judas Swing model. It derives a higher-timeframe daily bias, defines New York kill zones, maps each session's premium and discount from the live range, and requires a sweep before a market structure shift confirms entry. Readers get a ready approach to arm setups only during active sessions and execute in the bias direction with clear, testable rules.
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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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Graph Theory: Network Flow of Commodities (Ford-Fulkerson Algorithm), Used as a Liquidity-Capacity Engine

Graph Theory: Network Flow of Commodities (Ford-Fulkerson Algorithm), Used as a Liquidity-Capacity Engine

The article presents an MQL5 Expert Advisor that adapts the Ford–Fulkerson max-flow method into a liquidity-capacity filter. Market structures—Swing Highs/Lows, Fair Value Gaps, Order Blocks, and Liquidity Pools—form a directed graph with edge capacities from volume, price reaction, distance, and structure quality. Maximum flow qualifies ICT setups, filters weak paths, and drives dynamic position sizing for a consistent, two-stage decision process.
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Neural networks made easy (Part 70): Closed-Form Policy Improvement Operators (CFPI)

Neural networks made easy (Part 70): Closed-Form Policy Improvement Operators (CFPI)

In this article, we will get acquainted with an algorithm that uses closed-form policy improvement operators to optimize Agent actions in offline mode.
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From Basic to Intermediate: Union (II)

From Basic to Intermediate: Union (II)

Today we have a very funny and quite interesting article. We will look at Union and will try to solve the problem discussed earlier. We'll also explore some unusual situations that can arise when using union in applications. The materials presented here are intended for didactic 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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Implementing Walk-Forward Efficiency Ratio Scoring in MQL5 to Detect Over-Optimized Strategies

Implementing Walk-Forward Efficiency Ratio Scoring in MQL5 to Detect Over-Optimized Strategies

Parameter optimization inside MetaTrader 5's Strategy Tester routinely produces strategies that perform well in-sample and collapse on forward data. This article builds a native MQL5 Walk-Forward Efficiency scoring engine that quantifies how much of a strategy's in-sample Sharpe ratio transfers to each out-of-sample window. The distribution is rendered as a CCanvas histogram and validated against real EURUSD Daily backtest data.
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Risk Manager for Trading Robots (Part I): Risk Control Include File for Expert Advisors

Risk Manager for Trading Robots (Part I): Risk Control Include File for Expert Advisors

Trading is characterized by high demands on risk management discipline. The article presents an analysis of the main reasons for traders' failures and proposes a technical solution in the form of the CEnhancedRiskManager class for the MQL5 platform. It includes practical testing on an aggressive grid EA.
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MetaTrader 5 Machine Learning Blueprint (Part 16): Nested CV for Unbiased Evaluation

MetaTrader 5 Machine Learning Blueprint (Part 16): Nested CV for Unbiased Evaluation

The article presents a V-in-V nested cross-validation pipeline for financial data that breaks leakage at three decision points: hyperparameter search, calibration, and final evaluation. A temporal three‑zone split isolates an inner walk‑forward search with the 1‑SE rule from an outer walk‑forward or CPCV evaluation, while OOF isotonic calibration is fitted independently. The resulting UnifiedValidationCalibrator delivers unbiased out‑of‑sample scores and well‑calibrated probabilities for deployment.
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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.
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Encoding Candlestick Patterns (Part 3): Frequency Analysis for Single Candlestick Type Structure

Encoding Candlestick Patterns (Part 3): Frequency Analysis for Single Candlestick Type Structure

This article introduces a frequency-analysis framework for encoded candlestick patterns in MQL5. By transforming candlesticks into alphabetic symbols, historical price action can be analyzed as a statistical sequence rather than a visual chart. Using GBPUSD and Gold across multiple timeframes, the study examines the occurrence frequency of individual candlestick types, identifies dominant market structures, and reveals the symmetry between bullish and bearish price movements. The results establish a quantitative foundation for pattern discovery and prepare the way for analyzing multi-candlestick sequences and their predictive potential in algorithmic trading systems.
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Community of Scientists Optimization (CoSO): Theory

Community of Scientists Optimization (CoSO): Theory

Secrets of effective optimization of trading strategies in metaheuristic approaches. Community of Scientists Optimization is a new population-based algorithm inspired by the mechanisms of the scientific community. Unlike traditional nature-inspired metaphors, CoSO models unique aspects of human scientific activity: publishing results in journals, competing for grants, and forming research teams.
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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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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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Self Optimizing Expert Advisors in MQL5 (Part 14): Viewing Data Transformations as Tuning Parameters of Our Feedback Controller

Self Optimizing Expert Advisors in MQL5 (Part 14): Viewing Data Transformations as Tuning Parameters of Our Feedback Controller

Preprocessing is a powerful yet quickly overlooked tuning parameter. It lives in the shadows of its bigger brothers: optimizers and shiny model architectures. Small percentage improvements here can have disproportionately large, compounding effects on profitability and risk. Too often, this largely unexplored science is boiled down to a simple routine, seen only as a means to an end, when in reality it is where signal can be directly amplified, or just as easily destroyed.
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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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Neural Networks in Trading: An Intelligent Forecast Pipeline (Sparse Mixture of Experts)

Neural Networks in Trading: An Intelligent Forecast Pipeline (Sparse Mixture of Experts)

We invite you to explore the practical implementation of a sparse mixture of experts block for time series in the OpenCL computing environment. This article provides a step-by-step explanation of how masked multi-window convolution works, as well as how gradient-based training is organized in the presence of multiple information streams.
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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.