Transforming Legacy Code — A Software Consultant’s Perspective

Adhithi Ravichandran
5 min readJan 25, 2024
Refactoring code

As a Software Consultant, many times I work with teams that have to deal with legacy code. Working with legacy code is a common challenge in software development. Transforming legacy code into efficient, maintainable code involves a strategic approach.

Not all legacy code is bad. Sometimes leaving them as-is, is probably the best course of action. I have some strategic steps that I follow to transform legacy code into something efficient and maintainable. Here’s my roadmap that might help you too:

Understand the Code

Once you are on a project the first step is to make sense of the code. Approaching code with your own preferences and bias on what it should looks like is not a good idea.

Before making any changes, spend time understanding the existing codebase. Identify its architecture, key components, and how they interact.

You can take notes and play around with the code yourself to obtain a sense of familiarity with the legacy codebase. This is also the time when you can talk to older team members who maybe aware of some of the technical decisions that were taken in the past. They will also be able to point you to the current challenges that they are facing with the codebase.

Write Tests

Once you have familiarized yourself with the codebase and architecture. It is time to get to work. Start by writing automated tests, especially if the legacy code lacks adequate test coverage. This ensures that any changes made to it, does not break existing functionality.

Focus on unit tests (write lots of them) for critical parts and add integration tests where necessary. End-to-End tests will test the entire workflow, and you can write some of them as well to have additional coverage.

This is an important step before you change anything in the codebase. This will boost your confidence in making changes.

Refactor Gradually

Refactor the code in small, manageable increments. It’s crucial to approach this process gradually. Rather than attempting large-scale overhauls, which can disrupt the system’s stability, focus on incremental improvements. This includes enhancing variable names, modularizing functions, and eliminating redundant code.

By doing so, you maintain the software’s integrity. Your existing tests should pass, validating that the refactor hasn’t broken the existing functionality.

Update Dependencies

Keeping dependencies updated is a non-negotiable aspect of software maintenance. However, updating libraries or frameworks should be more than just a routine task, it requires a strategic approach. Evaluate the benefits of newer versions against the risks and efforts involved in the update process. Ensure compatibility and allocate sufficient resources for thorough testing post updates.

Implement Coding Standards

This is a good time to establish coding standards for the team that everyone agrees upon. As a consultant, I advocate for clear, consistent standards that align with industry best practices. These standards should be living documents, evolving with the team and the technology.

They serve as a roadmap for both current team members and future contributors, ensuring that the codebase remains accessible and manageable.

Address Technical Debt

Identify and prioritize technical debt. This is something you work with both the product and the technical team together to come up with a plan on tackling the issues. You need to understand the long term and short term goals of the business before allocating time for the technical debt.

Create a plan to address these issues systematically, balancing between new feature development and maintaining the existing codebase. You need the buy in from the product and all the stakeholders before you invest time fixing technical debt.


In the world of software development, documentation is often the unsung hero. Comprehensive, up to date documentation is an important component of effective software maintenance. It facilitates onboarding, eases the handover process, and acts as a guidepost for future development efforts.

I always like to add technical documentation to the readme file on the code repository. This way you don’t have to go in search of the documentation and it is always tied to your code. This is also easier for new team members to find and use.

Code Reviews and Collaboration

I can’t stress code reviews and collaboration enough! I have worked with plenty of teams that do not have a code review culture. This is a huge problem because this will result in a culture where no one cares about the code and they do not have a shared accountability.

Both leadership and the developers should be sold into the concept of code reviews and its importance. Plenty of time should be allocated towards it, and it should not simply be a check off item on the list.

Encouraging code reviews and collaboration is not just about improving the code. It is also about building a team culture that values learning and mutual support. Diverse perspectives can lead to innovative solutions and more robust code. As a consultant, my role often involves facilitating these discussions, ensuring that they are constructive and aligned with the project’s goals.

The Last Resort: Rewrite the Application

Finally, there comes a point where a complete rewrite might be on the table. This is a significant decision, and it comes with risks and potential rewards. It should be considered only when the existing codebase is completely problematic and is hindering progress. Users should have significant issues with it, and developers should find it hard to maintain it any longer.

The decision to rewrite should be backed by thorough analysis and a clear understanding of the desired outcomes. Once all the stakeholders agree to a complete overhaul and rewrite of the application, it is time to bring in new ideas and technologies to the table and start over.

In summary, making legacy code more efficient is a combination of understanding the existing software, careful refactoring, testing, and maintaining good coding practices. It’s a gradual process that requires patience and careful planning.



Adhithi Ravichandran

Software Consultant, Author, Speaker, React|Next.js|React Native |GraphQL|Cypress Dev & Indian Classical Musician