code quality of ruby on rails

Are you concerned about issues, maintenance, and crashes in your Ruby on Rails application? It may be time to review the code quality of your application.

Before making any business decisions, it is always preferable to thoroughly understand the problem. But what if you could go further and prevent those problems from the start? This is where maintaining code quality in your Ruby on Rails application comes into play. When the code in your application is of excellent quality, it performs optimally.

Like to learn more about why it’s essential to validate the code quality of your Ruby on Rails application? Check out our blog on Why is it important to validate the code quality of my Ruby on Rails project?

Mallow has been in custom software development for over a decade, and we strongly believe in the importance of adhering to best practices to maintain code quality for all applications. We have witnessed this approach consistently improve the overall quality of the application, as this ultimately results in reduced maintenance hours and a better user experience.

After going through this article, you will understand how to measure the quality of your Ruby on Rails application’s code and discover useful tools that can assist you in the evaluation process.

What attributes define a code with high quality?

Smooth operation and long-term success of your application rely heavily on the quality of the code. Well-written and readable code, adherence to coding standards and best practices, appropriate documentation, efficient algorithms, and effective error handling are some important aspects of code with good quality.

Below mentioned are some points that give you an overview of the fundamental characteristics associated with good code quality.


Efficiency : Good code quality promotes efficient algorithms and data structures, minimising unnecessary computations and reducing time complexity. It emphasises proper resource management, such as efficient memory allocation and deallocation, preventing memory leaks and optimising resource utilisation.


Maintainability : High-quality code is characterised by its ease of maintenance. It is modular, comprising clearly defined interfaces facilitating communication between different components. Modifications can be made to the code without causing disruptions to other parts of the system.


The code should convey business logic : In many instances, you can’t always expect the same developer to take up your application’s task every time. And for you to not spend much on the development costs, the newly onboarded developers should be able to understand the code and business logic behind it clearly and start the development quickly.


Reliability and Reusability : An application’s code could be considered reliable if it works as intended and does not crash, hang, or produce unexpected results. It should handle error conditions gracefully and not introduce new bugs or security vulnerabilities.Reusability means the code can be used in different parts of the system or different systems altogether. It is designed with abstraction and encapsulation in mind, making it easy to reuse without modification.


Scalability : The application has been built with code that can handle increasing traffic and usage levels without degrading performance or stability.


Testability : When code is easily testable, it indicates it is well-structured, modular, and follows good coding practices. Testable code is designed to allow for comprehensive and efficient testing, enabling developers to write meaningful tests and identify potential issues early on. High testability promotes the codebase’s maintainability, extensibility, and robustness.


Security : Security scanning is a crucial aspect of ensuring the integrity and protection of code against potential vulnerabilities such as injection attacks, XSS and CSRF and other malicious attacks. It involves evaluating various security aspects, such as input validation, access control, and data encryption, to identify potential weaknesses that can be exploited.

What approach needs to be utilised to assess a Ruby on Rails application?

1. Use code analysis tools to evaluate the quality.

To check on the code quality of your Ruby on Rails application, you can use tools like RuboCopRubycritic and Reek. Such code analysis tools can help identify code quality issues, such as code smells, anti-patterns, and performance bottlenecks. By identifying these issues, developers can improve the quality of their code and ensure that it is maintainable and scalable.

For example, RuboCop performs a static analysis of the codebase and checks for typical code quality issues such as syntax errors, indentation, and style consistency.

The tool can improve their codebase’s readability, maintainability, and overall quality. The tool can be customised to match the specific needs of the project. It can be integrated with continuous integration and delivery (CI/CD) pipelines to catch issues early in development.

system data

Hence, using code analysis tools can help developers identify and fix issues in their code, resulting in better quality, more secure, and more performant applications.

2. Code complexity metrics

You can use code complexity metrics to evaluate the complexity of your codebase. Metrics like Cyclomatic Complexity, Lines of Code, and Maintainability Index can give you insights into the quality and maintainability of your code. We can use gems like Rubocop, which offers assistance to evaluate these metrics.

3. Performance

The Bullet gem enables developers to build high-performing applications with improved response times and better database optimisation by detecting and handling N+1 queries, suggesting eager loading strategies, and delivering real-time notifications. Integrating the Bullet gem into the development workflow can create a more fluid and efficient application experience for end users.

The PG Hero gem provides powerful tools for improving PostgreSQL database performance for Ruby on Rails developers. Developers may discover and address performance bottlenecks by employing real-time query monitoring, index utilisation analysis, and the detection of database bloat. The PG Hero gem enables developers to fine-tune their apps for the best performance by monitoring disk space utilisation and making query optimisation recommendations.

Performance metrics measure how efficiently the code runs. This includes factors such as response time, memory usage, and CPU utilisation. APM tools like NewRelicScoutAPM, and Datadog are commonly used to check performance-related metrics. You also can check Hosted server’s (Cloud infrastructure) metrics to know about the memory and CPU utilisations.

4. Security

Security scanning measures how secure the code is against potential vulnerabilities and Brakeman attacks. To aid in this process, dedicated tools are available, such as Zap, which can assist in scanning and assessing the security of your code. These tools help detect vulnerabilities and provide insights into areas requiring attention or improvement. By incorporating security scanning measures into your development workflow, you can proactively enhance the security posture of your application and safeguard it against potential threats.

Interested in knowing more about security assessment using Brakeman? Check out this documentation from Brakeman.

5. Code Coverage

Code coverage measures how much of a codebase is executed during automated testing. It is an essential metric for maintaining code quality because it helps to identify areas of the code that are not being tested adequately. This also helps to identify bugs and errors, ensure maintainability, support refactoring efforts, and give developers the confidence they need to produce high-quality code. You can use tools like SimpleCov to ensure the code coverage is appropriately handled. Below attached is an image that would give you an idea of what the results from SimpleCov would look like.

Code Coverage

Your Go-to Ruby on Rails code quality checklist

Improving your application to achieve its best version is an ongoing process that evolves. Always seeking inspiration and shaping the application to meet your customers’ needs is essential.

ruby on rails



Young man works on a mobile application for data collection and analysis. Flat 2D character. Concept for web design.

Below is a sample checklist to help you maintain good code quality in your Ruby on Rails application. However, remember that this is a fundamental starting point, and you can customise the checklist to suit your specific needs.

What should I do if my application falls short in terms of code quality?


You now have an idea of how to measure the code quality of your Ruby on Rails application. You also have a picture of the best practices you need to follow to maintain the code in good quality and why it is necessary to do so.

You’ll likely find yourself in one of the following two positions.

The first situation would be that your code quality isn’t high. If you find yourself in this position, you need to take action. As your first step, start a conversation with your current development team and show them what you’ve found. This could involve conducting a code review, using automated tools to scan the code, or seeking the input of other experienced developers.

Once the issues have been identified, a plan should be developed to address them. If you’re still uncomfortable, evaluating other development teams may be something you need to look into next.

Are you considering working with Mallow? Please check our blog Is my Ruby on Rails application right fit to be built by Mallow? to ensure whether we are right for you.

The other situation you might find yourself in is your code quality is up to or near the industry standard. If you find this to be the case for you, one important thing to remember is that technology is constantly evolving. And there’s always something new to learn. Keep up with the latest trends, technologies, and programming languages to ensure your code remains cutting-edge and best-in-performance.

Still need any further clarifications or feel like we can help you out in enhancing the code quality of your Ruby on Rails application? Please reach out to our team.



Prakash is an esteemed Technical Lead at Mallow, celebrated for his outstanding technical and analytical skills. With over 9 years of experience in the field, he has cultivated a stellar reputation among clients for his ability to deliver exceptional solutions. Prakash's in-depth knowledge of complex systems and emerging technologies allows him to consistently provide innovative and effective results. Alongside his professional achievements, Prakash finds solace and joy in playing cricket during his free time.

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