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Modernization agencies in Cologne compared
Every established company has at least one system nobody likes to touch but everybody needs. These agencies modernize and migrate legacy systems, sorted by technology, minimum budget, and verified proof.
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Guide
Three ways out of a legacy system
A full rebuild replaces the old system entirely, with the greatest risk but also the greatest freedom to improve processes along the way. A step-by-step modernization retires parts of the system one at a time while the rest keeps running, more work to plan but considerably lower risk, since operations never come to a complete stop. A pure platform migration carries the existing logic largely unchanged onto new infrastructure, the fastest to implement, but it doesn't fix structural problems in the code itself. Which path is right depends on how critical the system is and how much risk the company can carry.
What matters when choosing an agency
Experience with the old technology is surprisingly often the bottleneck: an agency needs to understand the legacy system before it can replace it. Ask specifically who on the team actually reads the old language or platform, not just who writes the new one.
A documented approach for step-by-step retirement lowers risk considerably compared to a big-bang cutover on a single date. Ask for a concrete migration plan with intermediate steps, not just an end date.
Data migration is often the underestimated part of legacy projects: old data structures rarely contain documented edge cases that have accumulated over years. And clarify how ongoing operations are kept running during the migration. A system outage during the changeover can end up costing more than the entire project.
What modernization costs
€100 to €180 per hour is common. A pure platform migration without structural changes costs €20,000 to €60,000. A step-by-step modernization with several retirement phases runs €60,000 to €200,000 and often spans six to eighteen months. A full rebuild costs roughly the same as a comparable custom software project, usually starting at €100,000.
Typical modernization projects
Replacing a desktop application with a web application. Migrating an old database to a modern, maintainable platform. Step-by-step modernization of a monolithic system into better maintainable, separated components. Taking over a system with no remaining documentation or original development team.
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Frequently asked questions
Modernization agencies: questions and answers
What does modernizing a legacy system cost?
A pure platform migration costs €20,000 to €60,000, a step-by-step modernization €60,000 to €200,000, a full rebuild usually from €100,000. Agencies charge €100 to €180 per hour.
Rebuild from scratch or modernize the existing system?
Depends on the condition and criticality of the system. If the code is fundamentally sound and only the technology is outdated, a step-by-step modernization is often enough. If the structure itself is the problem, or nobody understands the system anymore, a rebuild usually becomes more economical, even though it looks more expensive at first.
How risky is retiring a legacy system?
The biggest risk lies in an abrupt cutover on a single date. A step-by-step retirement with intermediate steps and a fallback option lowers this risk considerably, but needs more planning upfront. An agency without a concrete migration concept is probably underestimating this risk.
How long does legacy modernization take?
A pure platform migration wraps up in two to four months. A step-by-step modernization usually runs six to eighteen months, depending on how many parts of the system get replaced. A full rebuild takes about as long as a comparable custom software project built from scratch.