Freelancer profile translated to English.
Back to original languageAbout Vadim
Java/Spring expert for performance optimization of grown systems. 27 years of professional experience in software development, 16 of which with Spring – available immediately.
What customers specifically get:
- Accelerated insurance batch migration from 225 minutes to 90 seconds (factor 180).
- Reduced latency in production systems by a factor of 10-20.
- Halved database storage requirements and build times without loss of functionality.
- Built scalable architectures for several million records per day.
Industry experience: Banks, insurance companies, telecommunications – including Deutsche Bank, T-Systems/Deutsche Telekom, Freenet, and several medium-sized companies.
How I work:
- Hands-on with code, not just at the slide level.
- Performance analysis and targeted optimization instead of general new build recommendations.
- Complexity reduction of existing architectures – fewer dependencies, less code, less maintenance effort, without loss of functionality.
- Architecture reviews with concrete, actionable next steps.
- Building monitoring and observability where transparency is lacking.
- Knowledge transfer to the team so that the improvement remains when the project ends.
Tech stack: Java, Spring Boot, PostgreSQL, Kafka, Spring Batch, Svelte, TypeScript, Docker.
Gladly for complex, grown systems with real performance pressure or upcoming migrations.
Does this sound like your project? Write to me – in a short conversation, we will clarify whether and how I can help specifically.
German
Native or bilingual
English
Conversational
Russian
Native or bilingual
Remote only
Primarily works remotely
Experience
- adesso SEAI-powered Staffing Matching ToolSOFTWARE PUBLISHINGApril 2026 - June 2026 (2 months)Frankfurt am Main, GermanyadStaff – AI-powered matching prototype between bench developers and open customer ticketsIn a corporation with hundreds of staffable employees, manually assigning developers to open project requests is a massive time sink for team leads and account managers – good candidates are regularly overlooked if the responsible lead doesn't have them in mind.Successes and tasks:
- Identified the problem, developed a solution concept, and implemented it entirely on my own initiative during bench time, without additional budget
- Developed a three-stage LLM pipeline: cost-effective keyword pre-selection, semantic LLM scoring only for top candidates, caching to avoid redundant LLM calls
- Conducted model comparison of several LLMs and made data-driven decisions
- Verified self-reinforcing feedback loop: users voluntarily enriched their profiles after seeing incomplete match scores
- Designed and implemented a complete role and authorization concept with automatic derivation from the organizational hierarchy
- Used own open-source error handling framework (Guard4j) for central error classification across all bounded contexts
Technologies:- Backend: Java 25, Spring Boot 4
- Frontend: Svelte 5
- Database: PostgreSQL (Full-text search, JSONB)
- Infrastructure: Docker, Traefik, Ansible
- AI: LLM Integration (Claude, Qwen, GPT-OSS)
- Eigenprojekt / Open SourceTexivia – Framework-agnostic TypeScript RouterSOFTWARE PUBLISHINGMarch 2026 - March 2026Wiesbaden, GermanyIn-house development of a minimalist, framework-agnostic TypeScript router: 160 lines, 1.4 kB gzipped, zero dependencies – more compact than all compared alternatives (TanStack Router, Vue Router, navigo, wouter). Compiles all routes at startup into a single Regex; navigation is a single exec() call, regardless of the number of routes. Integration via standard DOM events instead of framework-specific adapters.Tasks in the project:
- Complete in-house development including architecture, implementation, testing, and npm publication
- Compiled Regex routing engine: all routes compiled into a Regex, O(1) matching regardless of the number of routes
- Dynamic route parameters with constraints (e.g., {id:\d+}), async navigation handlers for auth checks and data preloading
- Automatic link interception without special components, event-driven via standard DOM CustomEvents
- Performed and documented comparative benchmark against four established routers (code size, bundle size, dependencies)
- Implemented example applications for Svelte 5 and Vue 3
- Eigenprojekt / Open SourceNegotex – Orchestrator-free BPMN Workflow Engine for Regulated IndustriesSOFTWARE PUBLISHINGJanuary 2026 - Today (7 months)Wiesbaden, GermanyNegotex compiles BPMN process definitions directly into Kafka topologies – each edge becomes a topic, each node a stateless stream processor. No central orchestrator, no database polling, no single point of failure. Developed for industries with high compliance requirements where gapless, tamper-proof audit trails are mandatory.Successes and tasks:
- Developed architecture concept: BPMN execution model on nine orthogonal
- Reduced primitives (Map, Fork, Join, Choice, Merge, Filter, Wait, Trigger, Terminate)
- Designed and implemented cryptographic audit trails: envelope hash chains (SHA-256, deterministically canonicalized) as an alternative to blockchain overhead
- Implemented Java runtime: 14-module Maven project, ~2,600 lines, BUILD SUCCESS
- Complete architecture documentation: arc42 system document, 36 Architecture Decision Records across seven architecture levels
- Designed open-core model: Community Edition (Apache 2.0) fully production-ready, Enterprise extension for Kubernetes operation planned
Status: Active development, Community Edition usable in production. OSS launch planned for summer 2026.Technologies:- Backend: Java 21+ (Virtual Threads), Kafka 4
- Databases: TimescaleDB, Valkey
- Observability: VictoriaMetrics
- DevOps: Maven, Docker Compose, Kubernetes (Enterprise)
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Education
- -Fernuniversität in Hagen2008Computer Science
- -University of Hamburg1998Physik