Short Answer
Yes. We regularly work with inherited, outdated, and undocumented codebases. Most businesses do not have the luxury of starting fresh. They have systems that are already running, already holding data, and already embedded in their operations. We assess what you have, identify what needs to change, and find the most practical path forward.
What Working With Legacy Code Actually Involves
Legacy code is any codebase where making changes is significantly harder than it should be. This might be because the original developers are gone, the documentation is missing, the technology is outdated, or the architecture has been stretched beyond its original design.
Working with legacy code starts with understanding it. Before we change anything, we need to know what the system does, how it does it, and why. This means reading code, tracing data flows, mapping dependencies, and talking to the people who use the system daily. The people who operate a system often understand its behaviour better than any documentation.
Once we understand the system, we can make informed decisions about what to do with it. The options exist on a spectrum:
- Stabilise and maintain. Fix critical bugs, patch security vulnerabilities, and keep it running. This is the right choice when the system works well enough and replacement is not justified.
- Incrementally modernise. Replace components one at a time, extracting modules, adding APIs, and upgrading dependencies, without a full rewrite. This is the most common path.
- Wrap and extend. Leave the legacy system in place but build new functionality around it, connecting through APIs or data bridges. The old system handles what it handles well; new systems handle the rest.
- Replace. When the technical debt is too deep, the technology is truly obsolete, or the system’s architecture fundamentally cannot support what the business needs, replacement is the honest recommendation.
Why Businesses Need This
Most businesses arrive at this question because they are stuck. They have a system that works but is painful to change. The developer who built it has moved on. The technology it uses is falling behind. New requirements keep coming, and each one is harder and more expensive to implement than the last.
The instinct is often to rebuild from scratch, but that is rarely the best first step. A legacy system that has been running for years contains encoded business knowledge: the rules, edge cases, and workflows that were learned through experience. A rebuild risks losing all of that.
What to Look For
- Willingness to assess before prescribing. Any partner who tells you to rebuild before understanding what you have is not being thorough. Assessment comes first.
- Experience with older technology. Legacy systems run on everything from PHP 5 to classic ASP to Python 2. You need someone who can read and understand code in technologies that are no longer fashionable.
- A practical mindset. Legacy work is not glamorous. It requires patience, detective work, and the willingness to make pragmatic decisions rather than idealistic ones.
- Clear communication about risk. Every change to a legacy system carries risk. You need a partner who communicates what could go wrong and has a plan for when it does.
Common Mistakes
- Rewriting before understanding. The “let’s just rebuild it” instinct destroys more value than it creates. Understand first, then decide.
- Assuming legacy means broken. Many legacy systems work perfectly well. “Legacy” describes the technology and maintainability, not the business value.
- Ignoring the data. The most critical part of any legacy system is usually the data it holds. Any modernisation plan must start with data preservation and migration.
- Expecting modern development speed. Legacy codebases are slower to work with. There are fewer tests, less documentation, and more hidden dependencies. Set expectations accordingly.
How We Approach This
Legacy work is a significant part of what we do. See Legacy Modernisation for how we structure these engagements. We start with an assessment, give you an honest view of the system’s condition, and present options with clear trade-offs. If the best answer is to keep the system running with minimal changes, we will tell you that.
The Practical Answer
We can work with almost any codebase regardless of age, language, or condition. The question is not whether we can, but what the most cost-effective approach is for your specific situation. You can find related reading throughout the Knowledge Center.
Disclaimer: The information provided in this article is for general guidance only and does not override or replace any terms in your contract. While we aim to offer helpful insights through our Knowledge Center, the accuracy of content in this section is not guaranteed.
Written by
Alex
CEO
I’m a software developer and CEO of Digital Royalty, helping growing teams scale their SaaS platforms without losing quality, visibility, or control. I focus on building structured, maintainable systems with clear processes, reporting, and accountability. With over a decade of experience across agency and in-house roles, I specialise in delivering long-term, scalable solutions that support complex, evolving products.
