5 Code Refactoring Techniques For Writing Clean Code

Did you know that developers spend up to 42% of their time dealing with technical debt? Without regular refactoring, codebases can quickly become cluttered, error-prone, and difficult to scale or debug. Fortunately, there are several effective techniques to tackle messy code, and choosing the right one depends on your project scope, team practices, and long-term maintainability goals. In this article, we’ll explore 5 code refactoring techniques to help you write cleaner, more maintainable code. Let’s get started!

What is Code Refactoring?

Code refactoring is the structured process of improving the internal design, clarity, and maintainability of a software codebase, without altering its external behavior. It’s important in improving code quality and reducing technical debt by reorganizing, simplifying, or fine-tuning the code to make it more efficient, modular, and easier for developers to read and work with.

People often confuse code refactoring with optimization, since both involve changing code, but the intent is completely different. You can check key differences in the table below:

Benefits of Code Refactoring

When code is intentionally refactored, it unlocks a range of long-term advantages, such as:

✅ Easier understanding – Clearer structure and naming make the codebase easier for teams to read, navigate, and maintain.

✅ Faster tech adoption – Clean, decoupled code makes it simpler to upgrade libraries or adopt new technologies without breaking things.

✅ Fewer hidden issues – Refactoring eliminates code smells that can lead to bugs, bottlenecks, and technical debt. This kind of debt can cost organizations an average of $3.61 per line of code annually.

✅ More reusable components – Modular, well-defined structures support reuse across features and teams, speeding up development.

✅ Smoother scaling – A clean foundation makes it easier to introduce new features or expand the system without major rewrites.

✅ Lower maintenance overhead – Simplified code reduces debugging time and reduces the effort needed for routine updates, leading to a resulting in maintenance costs by up to 30%.

6 Code Refactoring Techniques to Try in 2025

1. Red-Green-Refactor Technique

Red-Green-Refactor is a fundamental technique in Test-Driven Development (TDD), a software development methodology that prioritizes writing tests before implementing the actual code. This step-by-step process includes three main phases:

🔴 Red – Begin by writing a test that fails. This test should target a specific feature or behavior that has not yet been implemented, ensuring that the test is both valid and capable of detecting the absence of the required functionality.

🟢 Green – Next, write the simplest possible code necessary to make the test pass. The focus during this phase is solely on passing the test, without concern for code quality or optimization.

🔵 Refactor – With the test now passing, refine and optimize the codebase while maintaining the test’s green status. This phase involves improving code structure, readability, and maintainability, all while using the test as a safeguard to confirm that functionality remains intact.

💡 Pro Tip

Implementing the Red-Green-Refactor technique effectively requires a disciplined, test-first mindset and maintaining that across a growing codebase can be challenging. Zencoder’s Unit Test Agent simplifies this process with realistic, editable tests that follow your project’s existing patterns and standards. It accelerates development by automatically generating both tests and implementation code, reinforcing each phase of the Red-Green-Refactor cycle and supporting a strong test-driven culture from the outset.

2. Refactoring Through Abstraction

Refactoring through abstraction involves identifying common functionality across multiple classes or methods and extracting that shared logic into an abstract class or interface. Abstracting shared behavior into a common parent or contract centralizes logic in a single location, making updates more straightforward and more consistent. It also aligns the codebase with core object-oriented principles such as DRY (Don't Repeat Yourself) and the Open/Closed Principle, leading to cleaner and more scalable architecture.

For example, imagine you are building a payment system that supports multiple payment methods, such as credit cards and PayPal. Initially, the logic for transaction validation is duplicated across the different payment classes. To streamline the system, you can refactor the shared validation logic into an abstract base class.

Here is how the code may look before refactoring:

Here is how it will look after refactoring through abstraction:

The inclusion of multiple methods, such as authorize and capture, highlights how shared functionality can coexist with method-specific implementations across different classes. This design makes it straightforward to introduce additional payment methods, such as Apple Pay or Bank Transfer, with minimal code duplication.

💡 Pro Tip

While refactoring through abstraction helps maintain a clean architecture, identifying and restructuring duplicated logic across a large codebase can be tedious and error-prone. Zencoder’s Code Review Agent helps streamline this process with intelligent, context-aware insights that highlight opportunities to apply abstraction effectively. It helps improve design quality with actionable feedback that promotes consistent, maintainable, and standards-aligned code across your project.

3. Composing

Composing is a refactoring technique aimed at decomposing large classes or methods into smaller, more focused components. The primary objective is to ensure that each unit adheres to the Single Responsibility Principle. This methodology promotes a modular, well-organized codebase, making it easier to understand, evolve, and extend over time.

To decompose large classes into smaller ones, you should:

• Identify complexity – Look for large methods or classes managing multiple responsibilities.
• Extract methods – Isolate distinct logic into smaller, clearly named methods.
• Introduce supporting classes – Group related behavior into separate, focused classes where appropriate.
• Apply dependency injection – Pass dependencies into classes rather than creating them internally.
• Use descriptive naming – Choose method and class names that clearly convey their purpose.
• Refactor incrementally – Improve the structure gradually, focusing on one area at a time.

💡 Pro Tip

As your project is organized into multiple well-structured packages, keeping everything consistent during updates can get tricky. Zencoder’s Multi-File Editing feature makes this easier by launching an AI-powered coding session that suggests coordinated changes across multiple files in your workspace. With this feature, you can:

• Identify and recommend uniform changes across multiple files
• Implement edits directly within your editor
• Review all modifications with side-by-side comparisons to ensure precision and full control

4. Moving Features Between Objects

This refactoring technique shifts responsibilities or methods between classes to improve cohesion and reduce coupling, making the code more organized and less dependent on other parts of the code. Shifting code or functionality to the most appropriate class results in a more modular, intuitive, and maintainable design. This leads to cleaner separation of concerns and facilitates future scalability and flexibility.

For example, suppose you have a Customer class that contains a method for calculating a discount based on order history. However, this logic might be more appropriately placed in the Order class or a separate DiscountCalculator class, as it's not directly part of the customer’s core responsibilities.

5. Simplifying Methods

This approach aims to enhance the clarity, readability, and maintainability of code by focusing on two key techniques:

Simplifying Conditional Expressions

Over time, conditional statements in code can become increasingly complex and difficult to maintain. To improve clarity and logic, these expressions can be refactored using several techniques, including:

• Consolidating conditional expressions.
• Consolidating duplicate conditional fragments.
• Decomposing conditionals.
• Replacing conditionals with polymorphism.
• Removing control flags.
• Replacing nested conditionals with guard clauses.

Simplifying Method Calls

This technique focuses on making method calls more intuitive and easier to understand by simplifying class interactions and refining method interfaces. Common refactoring methods include:

• Adding or removing parameters.
• Introducing new parameters.
• Replacing parameters with explicit methods or method calls.
• Parameterizing methods.
• Separating queries from modifiers.
• Preserving the whole object.
• Removing setting methods.

6. Preparatory Refactoring

Preparatory refactoring is a smart way to improve code when you spot opportunities during the development of new features. Instead of putting off necessary changes, this approach weaves refactoring into the regular development process, helping teams tackle technical debt early on. Cleaning up the codebase early in the process makes future work easier, reduces costs, and helps you use resources more efficiently. In the long run, investing in early refactoring makes your app easier to maintain and grow.

💡 Pro Tip

Making structural changes during active development can often lead to missed edge cases, broken dependencies, or inconsistencies across the codebase. Zencoder’s Coding Agent is eliminates those risks by helping you streamline improvements as you build. Instead of juggling structural changes and new features separately, the Coding Agent helps you clean up and restructure code safely, with minimal disruption to your workflow.

With this feature, you can:

• Identify and clean up broken or outdated code while developing new functionality
• Simplify complex logic and align changes across multiple files
• Automate repetitive structural updates so you can focus on high-impact work

Overview table: Best use cases for Code Refactoring Techniques

Summary of application:

• Use Red-Green-Refactor for TDD workflows and when you want to tightly couple refactoring with automated testing.
• Apply Refactoring Through Abstraction when you find repeated patterns or logic across multiple places and want to enforce clean architecture.
• Choose Composing when classes or methods become unwieldy, signaling a need for smaller, focused components.
• Opt for Moving Features Between Objects when logic or data is not in its most logical or maintainable location.
• Use Simplifying Methods to tackle convoluted logic or improve the interface and readability of existing methods.
• Employ Preparatory Refactoring proactively when extending a codebase, to address technical debt before it hinders further development

Best Practices for Better Code Refactoring

To ensure the refactoring process is effective and doesn't compromise software quality, follow these five best practices:

• Collaborate with QA early – Involve the quality assurance team during refactoring to prevent introducing new defects. Their validation helps ensure the updated code maintains expected functionality and reliability.
• Leverage automation tools – Use automated tools for code analysis, testing, and refactoring to enhance efficiency and reduce errors. Static analyzers, linters, and test frameworks can help enforce standards and detect potential issues early.
• Refactor incrementally – Apply small, focused changes to minimize risk and maintain stability. Incremental updates make it easier to isolate and resolve any issues that arise during the process.
• Separate refactoring from debugging – Avoid combining bug fixing with refactoring to maintain clarity and reduce complexity. Address existing defects before refactoring, and treat any new issues separately.
• Eliminate code duplication – Prioritize removing redundant code to reduce inconsistencies and simplify maintenance. Consolidate common logic into reusable components such as utility methods or abstract classes.

How Can Zencoder Help You Write Clean Code

Zencoder is a powerful AI coding agent designed to streamline the software development lifecycle (SDLC) by increasing productivity, accuracy, and creativity. Using advanced Repo Grokking™ technology, Zencoder deeply analyzes your entire codebase, recognizing structural patterns, architectural designs, and custom implementations. This strong contextual insight enables Zencoder to offer precise, context-aware recommendations to speed up and enhance coding, debugging, and optimization.

It works effortlessly with your current development setup, supporting 70+ programming languages and integrating smoothly with popular IDEs like Visual Studio Code and JetBrains.

Here are some of Zencoder features to help you with keeping your code clean:

1️⃣ Integrations – Zencoder seamlessly integrates with 20+ developer environments, making your entire development process smoother. It’s the only AI coding assistant with this level of integration support.

2️⃣ Code Completion – Speed up your workflow with smart, real-time code suggestions. It understands your current context to provide accurate, relevant completions, reducing errors and helping you keep your momentum.

3️⃣ Code Generation – Develop faster with clean, context-aware code automatically added to your project. It delivers production-ready code that boosts speed, improves efficiency, and keeps your workflow consistent.

4️⃣ Chat Assistant – Get real-time, context-aware support with Zencoder’s intelligent chat assistant. From accurate answers to tailored coding advice, it’s designed to enhance your productivity and simplify your development process.

5️⃣ Docstring Generation – Make your code easier to understand and maintain with AI-powered docstrings. Zencoder automatically analyzes your code and generates clear, detailed documentation to boost comprehension and support better collaboration.

Sign up today and speed up your refactoring with our powerful features!

FAQs:

1. When is the optimal time to refactor code during the development cycle?

Code refactoring is most effective when done before adding new features, after a product launch, during efforts to resolve bugs or reduce technical debt, and when onboarding new team members. These stages provide key opportunities to improve code quality, making the codebase more maintainable and easier to work with.

2. Can refactoring introduce bugs into the codebase?

Refactoring can potentially introduce bugs; however, this risk is significantly minimized through comprehensive testing practices. Utilizing automated test suites and involving QA teams throughout the process helps ensure that the application continues to function correctly after changes are made.

3. Does refactoring improve performance?

Refactoring can improve performance, but that’s not always its primary goal. The main aim is to make the code more readable, maintainable, and scalable. However, simplifying logic or removing redundant operations during refactoring can lead to performance gains.

4. What are the challenges of refactoring?

Some common challenges include understanding legacy code, ensuring existing functionality isn’t broken, managing dependencies, and having sufficient test coverage. Without a solid understanding of the system and good testing practices, refactoring can introduce new bugs.