Modernize legacy systems & make AI-generated code production-ready – Fullstack Developer Freelance
Java, React, PHP – I take over unmaintainable legacy systems and chaotic AI-generated applications. Secure, scalable, and built for real-world use.
❌ "Our AI prototype is not deployable"
❌ "Legacy PHP keeps breaking"
✅ Solution: Refactoring + modern React UIs
My Specializations
I bring order to technical standstill
No generic landing pages. Production-ready architecture for companies solving real problems.
Legacy modernization
Java 8, old PHP monoliths, or unmaintainable Ajax spaghetti? I migrate step by step to modern stacks (Spring Boot, React, Tailwind).
Make AI-generated code production-ready
Your AI-generated prototype has no auth, no logging, no tests? I build the missing backend & frontend around it and make it maintainable.
Refactoring + React UI
You have an existing backend (Java/PHP) but an outdated interface? I design/implement a modern React UI – performant and accessible.
What you do not need from me
- ✖️ Generic AI landing pages without real value
- ✖️ Fast prototypes that fail in production
- ✖️ Unmaintainable "copy-paste" chatbot code
- ✖️ Pure web design without backend expertise
Instead: Architecture, stability, and a UI that truly works.
"I already had 3 AI prototypes built — none of them runs in the cloud."
– That is exactly where I step in.
From chaotic to production-ready
📉 Before: PHP monolith with 12k lines, no testing, constant outages.
📈 After: API-first architecture + React dashboard, outage rate -95%.
🤖 Before: AI-generated React app without backend — data only in localStorage.
⚡ After: Complete Java Spring API, PostgreSQL, JWT auth + clean UI.
AI & your concerns — plain talk
"Won't AI replace your work too?"
No. AI can build prototypes, but not production-ready systems with security, legacy databases, and domain-specific logic. That is exactly where I work — as an architect and problem solver.
"Why not just hire a junior with ChatGPT?"
Because you pay twice in the end: first for the prototype, then for me to fix it. I offer fixed prices for exactly this scenario — cheaper than trial and error.
"Do you also do web design?"
Not pure design. But as a full-stack developer with a strong UI sense, I build modern React interfaces — including implementation, not just visuals.
Your technical sparring partner for difficult software projects
I support companies when legacy systems slow delivery or AI prototypes are not production-ready. Focus: clear architecture, robust implementation, and fast, traceable outcomes.
Stack: Java, React, PHP, Spring Boot • Approach: pragmatic, transparent, production-focused.
Project or legacy burden?
Let's talk for 30 minutes free of charge — I will analyze your legacy or AI problem.
Send email: kontakt@jloos.devor via LinkedIn / Xing — contact details on request