It would be a lie to say that we will have a world where there would be no legacy code. The truth is legacy code is there to stay, and you, as a developer, need to learn how to maintain and conquer it.

That’s why in this article, we will explore the ways in which you can maintain legacy code made by other developers.

  1. What Is Legacy Code?
  2. How To Maintain Legacy Code Made By Other Developers
  3. Conclusion

How to Maintain Legacy Code

What Is Legacy Code?

Legacy code is the code that is maintained by a developer but not coded or written by them. In simple words, any code that you didn’t work falls under the category of legacy code.

There is another definition which terms legacy code as the code which the developer does not understand. In most cases, the code is inherited from others. The code can also be from the earlier version of the build or a code that is not well documented or have unit tests associated with them.

Why Is It Challenging To Manage Legacy Code?

Legacy code can be a challenge to maintain because of many reasons including:

  • The code is not well documented
  • Standard coding techniques are not used to code the application
  • The code is badly written
  • No unit tests are present in the code
  • Your lack of knowledge on which dependencies are used

And so on!

To ensure that the challenges are dealt with, you need to add the missing information to the legacy codebase routinely!

But how do you do that? Let’s explore!

How To Maintain Legacy Code Made By Other Developers

Get Started With Code Comments And Documentation

The best approach to get started with the legacy code is to read the available documentation and code comments. Almost every codebase comes with a README file, which explains how, when, and where the project works or intends to work. By going through it, you will get a starting point and also get a glimpse of what the original author wants from the codebase.

However, there can be projects with minimal README. Those projects or codebase can be very tough to maintain. It is also common for developers to stop writing comments as they dive deep into their projects.

Making Sense As A Whole

As mentioned, not all codebases are created equally. This leaves you with no other option but to try to understand it with a better perspective.

For instance, try to learn about the app’s purpose, the data flow within the app, and its feature set. By answering these, you will have a big picture where you can solve a smaller puzzle one by one.

By solving smaller puzzles, we mean that you try to run tests on it, maybe add a new feature or remove code to get a better grip on what’s happening.

Do Testing As Much As You Can

Clearly, testing is at the core of getting the code free from any bugs. However, it can let you break the app or codebase and give you a deep understanding of what it does.

By doing manual and unit tests thoroughly, you not only make it more maintainable but also enables the team to add more features to the codebase without completely breaking it.

Refactor Code

Code refactoring will enable you to improve the code gradually. This will also enable you to add comments whenever possible. Also, you should not rewrite the code as it can be time-consuming and lead to more bugs.


Coding has always been a collaborative skill. That’s why if you feel stuck, then always take the help of your fellow developers. They can ask questions and create a feedback loop that fine-tunes your codebase understanding. Also, getting hold of someone who worked previously on the codebase can change your ability to manage the codebase entirely.

Use Tools

Tools are there to ease your work, and many legacy-based tools can smoothen the legacy code maintenance process.


There is no doubt that managing codebase written by someone else can be a daunting task. It can easily tip you off from your psychological balance and make you feel worthless, helpless, and confused. To tackle it, you need to be kind on yourself. Moreover, you also need to be humble in your approach and lower expectations when needed.

Always start small and build upon it. With time and patience, you will be in full control over the codebase. As a developer, you should also provide the codebase as much value as possible in terms of comments, documentation, and unit testing.

So, what do you think about legacy code maintenance? Comment below and let us know.