Code that just “works” isn’t enough. High-quality code is easier to maintain, performs better, and is more reliable. Taking the time to improve code quality upfront saves you time and effort down the road. By focusing on readability, performance, maintainability, reliability, and security, teams can build software that lasts.

What is code quality?

In short, code quality means writing code that works well, is easy to understand, and can be easily updated or fixed. Good code is simple, efficient, secure, and easy to maintain. It should be clear enough for others to work with and flexible enough to handle future changes.

To achieve this, developers might turn to tools to improve code quality. These tools help identify potential issues, enforce best practices, and ensure code aligns with standards, making the process faster and easier.

What are the 5 pillars of code quality?

At the heart of great software are five key pillars of code quality—principles that shape code into something not just functional, but also efficient, adaptable, and resilient. The pillars of code quality help devs write code that works now and lasts over time.

1. Readability: Code should be clear and easy to follow, with proper naming guidelines, clear structure, and straightforward comments for any developer working on it.

2. Performance: Efficient code minimizes waste or excessive demand on the system, for fast execution and smooth user experiences, even under heavy loads.

3. Maintainability: Well-structured, modular code makes updates and bug fixes easier while reducing the risk of new problems cropping up.

4. Reliability and resiliency: Code should work correctly and recover quickly from unexpected issues, keeping the system stable under different conditions.

5. Security: Security is a key part of good coding, protecting applications from vulnerabilities and ensuring they stay safe from attacks or unauthorized access.

How to improve code quality in 8 steps

Writing good code is only half the job—keeping it high-quality means it’s reliable, easy to maintain, and ready for whatever comes next. 

Make your code readable, not just runnable

Clean, well-organized code simplifies the work and keeps projects on track. A clear structure avoids confusion and keeps things consistent. Static reviewers help with this, while AI-powered code review tools like Trag go further by spotting unclear names, messy logic, and layout issues, making code easier to work with.

Keep it simple (KISS)

Keeping things simple makes code easier to understand, work with, and maintain. The KISS principle—Keep It Simple, Stupid—reminds us to avoid overcomplicating things. Clean, straightforward code lowers the chance of bugs, speeds up reviews, and makes updates less of a headache. Simplicity keeps projects moving (and developers happy).

Break it into reusable pieces

Breaking code into smaller, reusable parts makes it easier to manage, test, and update. Modular code reduces problems by dividing tasks into smaller, separate sections. Start by finding repeated logic or large functions, pull them into separate chunks, and test them on their own. This approach makes your code more efficient, and easier to build on later.

Don’t repeat yourself (DRY)

The DRY principle—Don’t Repeat Yourself—is all about avoiding duplication. Repeating the same logic creates extra work and makes updates harder. Instead, use reusable libraries, templates, or a code checker to simplify your code. This keeps things organized, saves time, and makes future changes practical.

Avoid hard-coded values

Hard-coded values might seem fine at first, but they make updates a pain. Instead, use configuration files, constants, or environment variables to keep your code flexible. This way, you only need to update things in one place—like a single file or variable—without digging through the entire codebase.

Version control is essential

Version control tools like Git help track changes in your code, showing what was modified, when, and by whom. They make it easier for multiple developers to work on the same project without overwriting each other’s work. If something goes wrong, you can roll back to an earlier version, resolve conflicts, and keep your project organized.

Refactor your code regularly

Refactoring is the process of improving your code’s structure and clarity without changing what it does. Look for “code smells” like duplicate logic, long functions, or unclear names. Plan small, focused changes, and test your code to make sure everything still works. Regular refactoring keeps your code clean and manageable as projects grow.

Optimize for performance

Optimizing for performance means writing code that runs faster and uses resources efficiently. Focus on improving algorithms to save time, minimize unnecessary I/O operations, and use caching to speed up repeated tasks. Small tweaks can make a big difference, especially in large applications or systems with heavy loads.

Good code vs. bad code

Good and bad code can be tricky to define because context matters. What’s clean and effective in one project might cause trouble in another. Still, there are common qualities that make code readable, maintainable, and reliable—and others that make it hard to work with. Let’s explore them.

Readability

Good code

• Uses meaningful variable and function names.

• Has a clean and logical structure (e.g., indentation, spacing, and consistent formatting).

• Includes inline comments sparingly to explain the "why" instead of the "what."

Bad code

• Has cryptic names like x1 or temp for variables.

• Lacks organization, making it hard to follow logic.

• Overuses or underuses comments, creating noise or confusion.

Performance

Good code

• Runs faster by using optimized logic and skipping unnecessary steps.

• Minimizes resource usage, keeping execution times short and smooth.

• Scales well, maintaining speed and reliability as demands grow.

Bad code

• Is slow and inefficient, due to poor logic or redundant steps.

• Struggles to scale, wastes resources, causing lag or crashes.

• Creates bugs and errors, frustrating users.

Maintainability

Good code

• Is organized into small, manageable functions or classes.

• Is free of duplicates (following the DRY principle).

• Includes clear documentation to make updates easy.

Bad code

• Is messy and repetitive, making updates risky and time-consuming.

• Lacks organization, forcing developers to guess the code’s purpose.

• Has little to no documentation, slowing fixes and changes.

Reliability and resiliency

Good code

• Is written to include input validation and error handling.

• Is designed to account for edge cases to ensure consistent behavior.

• Stays stable and dependable through updates.

Bad code

• Crashes easily due to missing fallbacks or error testing.

• Breaks unpredictably because of hidden components.

• Turns minor issues into time-consuming debugging sessions.

Security

Good code

• Is built following secure practices to minimize vulnerabilities.

• Is designed to properly handle unexpected inputs, preventing exploits or crashes.

• Aligns with security standards to ensure software protection.

Bad code

• Fails to follow secure practices, exposing apps to attacks.

• Mishandles inputs or skips necessary checks, exposing the software to risks.

• Lacks adherence to security standards, compromising the safety of the software.

Improve the quality of your code with Trag 

High-quality code requires more than just reviews. AI-powered code review tools like Trag automate checks for errors and inconsistencies and provides actionable insights that help you follow code review best practices, catch issues early, and keep your code clean and reliable.