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Refactor Legacy

Legacy application modernization

Your application is ageing, costly to maintain and slowing you down. We modernize it without breaking what works, in controlled steps.

01The need

A critical system still holds up but is becoming risky: obsolete technology, no one knows the code anymore, every change takes weeks. You want to modernize it without disrupting operations or rewriting blindly. We stabilize it first, then transform it.

02What we take on

  • Audit of the existing system and debt mapping
  • Progressive migration strategy
  • Refactoring and restoring test coverage
  • Updating frameworks and dependencies
  • Rebuilding documentation and knowledge
  • Security hardening and performance improvement

03How we work

No big bang: we move forward in reversible increments, with tests that catch any regression. You keep a working system in production at every step. We document along the way so your team can take back control.

04How we work with you

We start with a short audit, usually 3 to 5 days. We read the code, talk to the people who maintain it, and map the debt: what is fragile, what is no longer tested, what is blocking your changes. You come out with a costed, prioritized action plan, not a report that gathers dust.

Then we transform in reversible increments. Before touching a sensitive area, we put it back under tests: each step ships with a regression safety net and can be rolled back if needed. The system stays in production throughout, with regular demos so you can follow progress. We start with the workstreams that cut risk the most, and we adjust as we go depending on your context.

05What you get

In the end, the goal is simple: a system your team is no longer afraid to touch. Concretely, you walk away with:

  • Cleaner code that is easier to evolve
  • Technical debt mapped and reduced by priority
  • Test coverage that secures future changes
  • Up-to-date frameworks and dependencies, free of known flaws
  • Rebuilt documentation and knowledge transfer to your team

06When to call us

There is no magic threshold: if one of these signals rings true, a short audit is often enough to see clearly. We reply within 24 hours, and the first call is free.

  • The application is slowing down and every change takes weeks
  • Dependencies are obsolete or carry known vulnerabilities
  • Your team is afraid to touch it, or you are inheriting a codebase no one knows

Frequently asked questions

Should everything be rewritten, or can we migrate progressively?

In most cases, we migrate progressively. A full rewrite is risky and slow; we keep it for situations where the existing system is truly untenable. We move in reversible increments, keeping a working system in production at every step. The right balance is decided after the audit, depending on your scope.

How do you reduce technical debt without blocking production?

We start by mapping the debt and restoring test coverage, which makes changes safe. Then we tackle the debt in iterative workstreams, alongside your ongoing changes. The system stays shippable throughout: no multi-month freeze to rebuild everything.

What is the impact on users during the migration?

The goal is that they notice little or nothing. Because we move in reversible increments covered by regression tests, each step ships with a safety net. If a sensitive switchover is needed, we prepare it and support it in production. Intervention windows are defined together, depending on your operations.

Which legacy stacks and technologies do you support?

We are comfortable with the JavaScript and TypeScript ecosystem (React, Angular, Node.js, NestJS) on the target side, and we take over older existing codebases to evolve them. If your stack falls outside our core expertise, we tell you plainly on the first call. The short audit exists precisely to confirm feasibility before committing.

How do you estimate effort and cost?

Everything starts with a short audit, usually 3 to 5 days, which maps the debt and the real scope. From it we produce a costed action plan and a detailed quote within 48 hours. Depending on the context, we work on a day-rate or fixed-price basis. We reply within 24 hours, and the first call is free.

Let's take back control of your legacy.

A short audit gives you a clear view of the debt and a costed action plan.

Book a call