Backend systems, shipped reliably
I build, modernize, and scale backend systems for DACH enterprises — as a hands-on engineer or interim tech lead. 16+ years of production experience with Kotlin, Java, Spring Boot, PostgreSQL, and cloud infrastructure.
Freelance Backend Engineer & Tech Lead — Berlin, Germany
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How I can help
I work as an embedded freelancer or interim lead, typically on 3–6 month engagements.
Build and modernize backend systems
New services from scratch or incremental migration of legacy systems. I design the architecture, write the core code, and deliver a system your team can maintain after I leave.
Lead your backend team
Interim tech lead for 3–6 months. I establish practices, mentor developers, make architecture decisions, and transfer ownership when the engagement ends. You also get production code, not just advice.
Selected work
Anonymized summaries of recent engagements. References and details available on request.
Replacing 10–20-year-old production systems without stopping the factory
Senior Backend Engineer, embedded in the product team
Critical manufacturing execution systems running on legacy software. Too risky to replace all at once, too costly to keep patching.
- Reverse-engineered legacy interfaces and built integration layer for multi-system migration
- Halved CI pipeline time through test infrastructure and architecture improvements
- Delivered next-generation MES to production with ~10× performance improvement over the legacy system
- Evaluated database technologies for large reporting datasets (tables up to 40M rows, ~200 columns) and delivered a recommendation with PoC
From architecture to production launch in under two years
Backend Tech Lead, reporting to CPO, leading offshore developers
Commodity trading platform needed a backend lead who could define architecture and ship code — fast enough for a startup, reliable enough for financial transactions.
- Defined core backend architecture and led the team through platform go-live on time and within budget
- Onboarded and guided offshore developers during company transformation
- Managed Salesforce integration and vendor coordination, streamlining sales processes
Continuous delivery through a company restructuring
Development Lead, team of 4, primary inter-team contact
Major real estate company undergoing transformation — needed a dev lead who could keep shipping while the organization restructured.
- Led team of 4 through COVID and company restructuring, shipping continuously
- Built email classification pipeline that cut processing time from days to seconds
- Migrated core services from Java to Kotlin, accelerating and stabilizing feature delivery
- Built tenant applications for Germany and France, supporting onboarding for tens of thousands of tenants
- Implemented Auth0 SSO and centralized roles and permissions across the platform
- Added service-level caching, delivering ~2× faster request execution
- Introduced API and E2E testing across the landscape, reducing production defects
About
I'm Andrey, a backend engineer and tech lead based in Berlin. I've been building production systems for over 16 years — the kind where reliability matters and shortcuts become problems.
My work sits at the intersection of writing code and leading teams. I'm most useful when you need someone who can ship features, review architecture, unblock developers, and talk to stakeholders.
I work primarily in the JVM ecosystem (Kotlin, Java, Spring Boot) with PostgreSQL, Kafka, and cloud infrastructure on AWS and Azure. Before that, four years of compiler research at Universität des Saarlandes — building tools for automated testing and bug detection in GCC and LLVM.
At a glance
Languages
Education
References
Past clients and detailed project history available on LinkedIn
Let's work together
Available for interim engagements and project-based work. Remote or on-site in Berlin and across the DACH region.
I typically respond within 24 hours.