Software thatscales with you.
Your system runs — but every release takes longer, every new requirement meets resistance. Classic sign: technical debt. I help you reduce it in a structured way without putting your day-to-day operations at risk.
- I take responsibility for existing code — even when I didn't write it.
- Fixed prices after the discovery phase — no open-ended day-rate invoices, no surprises.
- Experience in test automation and quality assurance (ISTQB-certified).
Why mid-sized projects fit me.
I know the reality of mature codebases — and I know that modernisation is rarely a greenfield project.
My standard isn't to rewrite everything. My standard is to make the existing system gradually better, without your team feeling it in their daily work.
My name is Justin Eiletz. By day I work as a Quality Engineer at ab-data AG in Oldenburg, a mid-sized software company serving public administration. I've been involved in exactly this kind of modernisation work from the inside for years.
In freelance engagements I bring that experience to your codebase. Instead of a big-bang replatforming, I work in clearly scoped steps: first audit and risk assessment, then targeted refactorings, then new features on a solid base.
From assessment to a modern system.
Four phases that can each be commissioned individually. You decide after every step whether to continue.
- 01
Audit and roadmap
I analyse your codebase, document risks, and prioritise improvements. You receive a written report with backlog and fixed-price corridor — the basis for all further decisions.
- 02
Stabilisation
Before we build anything new, we make the existing system controllable: introduce tests, fix critical defects, harden the deployment pipeline. Small but tangible — usually within a few weeks.
- 03
Modernisation in steps
Modules are renewed in a targeted manner or replaced with modern solutions — but only where the value justifies the effort. Your system keeps running the entire time; users notice the change at most through speed and stability.
- 04
Handover to your team
On request I help your in-house engineers build their own architecture skills. The goal is not to be a permanent consultant, but for your team to continue independently.
What mid-sized clients ask me for.
Three task types that recurringly come up.
- 01
Replatforming a legacy application
A 10–15-year-old Java EE or PHP application is to be migrated to a modern Spring Boot or Node.js architecture — ideally piecewise, without downtime.
- 02
Internal tool or dashboard
Excel sheets or siloed solutions need to be replaced by a central web application with connections to existing databases. Concrete users, clear requirements, fast value.
- 03
Building test automation
An existing application has no or very few tests. With Selenium, Playwright, or Ranorex I build a robust test suite together with your team — ISTQB-aligned.
Code audit as a low-risk first step.
Every larger project starts with a structured assessment. For first-time projects of €15,000 or more, it is complimentary for you.
Structured analysis of your codebase with a written report, prioritised refactor backlog, and architecture recommendation. Included in the follow-up engagement for first-time projects of €15,000 or more.
- Written audit report (15–25 pages)
- Prioritised backlog with effort estimates
- Architecture recommendation and risk analysis
- Fixed-price corridor for implementation
The audit is valued at €2,490 in own work and is offset against the follow-up engagement for first-time projects of €15,000 or more. Without a follow-up engagement, the audit report still remains with you.
Request an auditWhat often comes up in the first call.
Three recurring points from first calls with mid-sized clients.
We already have an external provider. Does this still work?
Yes, both ways. I can work alongside an existing provider (e.g. as an architecture advisor) or accompany a gradual takeover. The important thing is that all parties are transparently informed.
How deep into the company do I have to grant access?
For the audit, read-only access to the repository and one or two conversations with stakeholders are enough. For implementation phases we agree on the necessary access individually — when in doubt, with time-limited accounts.
Do you work with our compliance requirements?
Yes. Data processing, confidentiality, and security guidelines are standard. I routinely sign NDAs and DPAs; data is processed exclusively on systems you have approved.
More on this in the blog
Background reading on the topic — writing rather than selling.
Assessment, not gut feeling.
A 30-minute first call clarifies whether an audit fits your situation. Complimentary, non-binding, no sales pressure.