Legacy software modernization without a big-bang rewrite
Old systems are rarely broken — they're just risky to change. We modernize your legacy software incrementally, using strangler-fig migration, containerization, and a test harness that de-risks every step. Your system stays in production throughout, and you keep control of pace and budget.
What we modernize
We cut your legacy system along its business domains and move it capability by capability into maintainable services — following the strangler-fig pattern, so the whole system is never on the line at once. New components are built in TypeScript and Python, data migrates in a controlled way to PostgreSQL, and the old application keeps running in parallel until the last path is cleanly retired. The result is a documented, testable codebase your team can extend without fear.
How we work
Before we replace anything, we wrap the existing behavior in a harness of integration and characterization tests, so each migration is verifiable rather than risky. We then break the cutover into small, deployable steps and show real progress in the live system every week. Every demo tells you what's migrated, what's next, and where the budget stands — no surprises, no waiting months for one big switch-over day.
The tech
We containerize the application with Docker and orchestrate it in Kubernetes, so the old and new states run side by side and roll out independently. Infrastructure is described reproducibly in Terraform, and data migrations run versioned against PostgreSQL. The stack — TypeScript, Python, Docker, Kubernetes, PostgreSQL, Terraform — is deliberately mainstream, so your team or any senior engineer can pick up maintenance cleanly.
Why Olio
You get senior-level engineering without committing to a senior hire — and no vendor lock-in, because we build for handoff: clean code, real tests, complete documentation. As a boutique agency out of Mönchengladbach, we work remote-first across Germany, Austria, Switzerland, and the wider EU, hosting EU-sovereign on Hetzner, GCP EU regions, or AWS Frankfurt. Modernization here isn't a prestige project — it's measurable progress in production-ready steps.
What incremental modernization gets you
- No big-bang rewrite — your system stays in production throughout the migration
- Every step de-risked by a test harness instead of switched over on a hope
- Weekly demos on the live system: you see progress, not just an invoice
- EU-sovereign, GDPR-compliant hosting on Hetzner, GCP EU, or AWS Frankfurt
- Reproducible infrastructure in Terraform — no vendor lock-in, portable anytime
- A handoff-ready, documented codebase your team can carry forward alone
Core Technologies
Let's modernize your legacy system, one step at a time
Common questions about legacy modernization
What does a legacy software modernization cost?
It depends on scope. A contained, incremental migration starts around the size of a simple MVP (roughly EUR 25,000–40,000); broader platforms with many domains and integrations move toward EUR 50,000–120,000. Because we deliver in small steps, you see value and cost trajectory early and can re-prioritize at any point.
How long does it take?
We usually ship the first production results within a few weeks — a contained modernization package in about 4–12 weeks. Since we work strangler-fig style, you don't wait months for one big switch-over day; you see measurable progress on the live system every week.
Why not a full rewrite?
A big-bang rewrite pauses product work, piles up risk, and often ends as a second legacy system. Retiring the old code incrementally keeps the system running throughout, makes every step verifiable with tests, and lets you pause or re-prioritize at any time — with no sunk investment.
Which technologies do you use?
New services in TypeScript and Python, containerization with Docker and Kubernetes, data on PostgreSQL, and infrastructure reproducibly in Terraform. The stack is deliberately mainstream so maintenance and handoff stay easy — and we adapt to your existing environment rather than forcing a foreign ecosystem on you.
Where is the data hosted?
EU-sovereign and GDPR-compliant — on Hetzner, in GCP EU regions, or AWS Frankfurt, depending on your requirements. We don't tie you to a provider: because the infrastructure is defined in Terraform, your setup stays portable at any time.
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