Legacy Modernisation
Legacy code slows every feature, ties up scarce developer capacity, and increases the risk of outages.
Legacy Modernisation Without Disruption
We modernise legacy systems step by step — through targeted refactoring, module replacement, or greenfield development on a modern stack — without endangering your live operations.
The essentials of Legacy Modernisation
- We modernise legacy systems step by step — through targeted refactoring, module replacement, or greenfield development — without endangering live operations.
- Before any change we analyse the codebase, architecture, and dependencies and honestly assess which parts are worth keeping and which should be replaced.
- We apply the strangler-fig pattern: new components emerge in parallel, functionality is redirected piece by piece, and the old system is decommissioned in a controlled way.
- Before changing old behaviour, we capture it with characterisation tests, so we don't unknowingly build in errors.
- We reconstruct and document the often undocumented knowledge locked in a few people's heads before it leaves with departing employees.
Inventory Analysis First
Before changing anything, we understand what's there. We analyse the codebase, architecture, and dependencies of your legacy system and assess which parts are worth keeping and which need to be replaced. The result is an honest inventory as the basis for an informed decision, not blind actionism.
Refactoring vs. Greenfield
Not every legacy system needs a complete rebuild. We choose the right path — refactoring existing code, incremental module replacement, or targeted greenfield development — and transparently evaluate effort, risk, and benefit for each option so you invest where leverage is greatest.
Strangler Fig Pattern
Big-bang migrations frequently fail. We apply the strangler fig pattern: new components emerge in parallel to the legacy system, functionality is redirected piece by piece, and the old system is decommissioned in a controlled manner. Live operations remain stable at every point.
Knowledge Preservation
Legacy systems often contain undocumented knowledge locked in a few people's heads. We reconstruct domain logic, document processes and interfaces, and secure the know-how before it leaves with departing employees — so the modernised system is comprehensibly documented and independently evolvable.
Modernisation without operational risk
Step-by-step replacement using the Strangler-Fig pattern keeps the legacy system live until its last part is cleanly replaced — instead of betting everything on one high-risk cutover date.
Inventory & knowledge capture
Map architecture, dependencies, and undocumented domain knowledge — before touching anything.
Prioritisation by debt matrix
Score modules by change frequency and defect density — modernise only costly debt, leave stable code untouched.
Build characterisation tests
Lock in existing behaviour with automated tests so refactoring cannot introduce silent regressions.
Incremental replacement (Strangler-Fig)
Replace module by module: the new system grows around the old one while operations run continuously.
Sign-off & knowledge transfer
Document each replaced unit, brief the team, and update the technical debt ledger.
Each phase delivers standalone value while keeping production stable.
What to modernise first?
Not all legacy code is equally harmful. Prioritisation follows two axes: how often a module is changed and how many defects it produces.
Modules in the top-right quadrant generate the highest costs — they are the right starting point.
What matters for Legacy Modernisation
In legacy modernisation, skill is separated by whether ongoing operations stay safe at every point in time. That is exactly where big-bang rebuilds fail, betting everything on a cut-over date that rarely holds. Step-by-step replacement following the strangler-fig pattern keeps the old system alive until its last part is cleanly replaced, delivering value continuously along the way.
Not every old line needs replacing, and recognising that saves the most money. Stable, rarely changed code does little harm despite its age; the expensive debt sits in the core that is touched constantly. Prioritising by change frequency and defect density shows where modernisation actually brings speed back, instead of polishing everywhere evenly.
Refactoring without test coverage is flying blind. Before old behaviour is changed, it must be captured by characterisation tests, otherwise you unknowingly build in errors no one knew before. And the undocumented knowledge of a few heads belongs reconstructed before modernisation, because securing it beforehand is cheaper than laboriously recovering it later.
Big bang fails often
Complete rebuilds in a single step are expensive and risky. Incremental replacement via the strangler fig pattern keeps operations stable and delivers continuous value — rather than betting everything on a deadline that rarely holds.
Inaction also has costs
An ageing system incurs silent costs: rising maintenance effort, security risks, and dependence on specialists. These costs are often higher than a planned modernisation — they just accumulate less visibly.
Secure knowledge first
Undocumented knowledge in legacy systems leaves with departing employees. Reconstructing and documenting it before modernisation is cheaper than trying to recover it later — and prevents the modernised system from becoming an undocumented black box too.
Legacy ready for tomorrow
With us you're always at the forefront of enterprise software development and benefit directly from our extensive development know-how. Together we examine your business processes, identify key optimization potential and develop individually tailored solutions. Your business goals and expectations are the focal point of everything we do.
Comprehensive technological expertise
We choose the stack per project by requirement and rely on established, future-proof technologies instead of niche dependencies.
Specialized in enterprise solutions
The real lever lies in clean interfaces: we integrate deeply into ERP, CRM and third-party systems instead of isolated solutions.
Years of experience in the software industry
From requirements analysis to operation after go-live, we know the pitfalls of large software projects.
Multidisciplinary expert team
Analysis, architecture, backend and operations come together in one team, without friction between disciplines.
Long-term business success
We build maintainable foundations that grow with your company, and stay by your side with support and further development.
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