About Nikolai
Über Dich
Senior Full-Stack Engineer with 13+ years of experience building scalable SaaS and enterprise web applications for EU and US clients.
Specializing in React, Next.js, and TypeScript on the frontend, with strong full-stack experience in Node.js, .NET, and Python. Focused on SaaS architecture, multi-tenant systems, and frontend system design.
Currently building production SaaS products:
SmartWMS – Multi-tenant warehouse management system
React, .NET 8, PostgreSQL, SignalR
InvoCore – German e-invoicing platform (XRechnung / ZUGFeRD compliant)
React, Python, FastAPI
Nootee – AI content automation platform with multi-LLM architecture
OpenAI, Claude, Gemini, RAG
Key experience (Auditdata, 6+ years):
– Designed micro-frontend architecture (Module Federation) adopted across multiple product teams (30,000+ users)
– Built React component system (Storybook-based design system), reducing UI delivery time by ~50%
– Contributed to React Native applications (iOS, Windows)
– Delivered complex frontend features in large-scale SaaS environment
– Reduced bundle sizes by ~40% and modernized legacy frontend systems
– Contributed to cross-team engineering standards and onboarding of developers
Tech stack:
React, Next.js, TypeScript, Node.js, .NET, Python, FastAPI, PostgreSQL, Redis, Azure, AWS, Docker, CI/CD, React Native, AI/LLM (OpenAI, Claude, Gemini)
Availability:
Senior / Lead / Staff Engineer roles
Remote (EU / US time zones)
Available immediately
English
Fluent
Russian
Native or bilingual
German
Basic
Can work on-site
Freiburg im Breisgau (up to 50km)
Experience
- FreelanceSenior Full Stack Developer (Freelance) Independent ContractorSeptember 2025 - Today (10 months)GermanyBuilding production SaaS products with AI/LLM integration: warehouse management, German e-invoicing, and AI-powered content automation platform.SmartWMS (smartwms.one)– Built multi-tenant warehouse management SaaS: 40 API modules, 150+ routes, real-time updates via SignalR– Technologies: React, TypeScript, Redux Toolkit, RTK Query, Webpack, .NET 8, PostgreSQL, SignalR, Docker, GitHub Actions– Landing: Next.js 14, Tailwind CSS, 17 localizations, Stripe payments (SEPA + cards)– Testing: xUnit (150+ files), Jest, Playwright E2E, CI/CD via Docker and GitHub Actions– Telegram AI agent for operational automation: inventory reports, shipment alerts, warehouse monitoringInvoCore (invocore.eu)– German e-invoicing SaaS (XRechnung, ZUGFeRD), GDPR-compliant multi-tenant system– Technologies: React, TypeScript, RTK Query, Python, FastAPI, PostgreSQL, Redis, Celery– Testing: pytest (294 tests), Playwright– Focus on invoice processing, automation workflows, and EU compliance requirementsNootee (nootee.com)– AI-powered content automation platform– Processes Git activity to generate and publish content (LinkedIn, Discord) and automate responses to GitHub issues– Multi-LLM architecture (OpenAI, Claude, Gemini) with pluggable provider system– RAG-based knowledge assistant integrated across SaaS products
- AuditdataSenior Software EngineerMarch 2019 - September 2025 (6 years and 6 months)Kiev City, KV, UkraineFull-stack engineer across frontend, backend, and mobile — core contributor to enterprise SaaS products serving healthcare professionals in 30+ countries.Key Achievements– Designed micro-frontend architecture (Module Federation) adopted across product teams, reducing integration conflicts by ~80%– Built React component library with 50+ components and Storybook documentation, reducing UI development time by ~50%– Co-initiated and developed React Native applications (iOS + Windows) outside the main roadmap — now in production and generating revenue– Contributed to delivery of critical Finance & Invoicing modules within a 2-month release cycle– Reduced frontend bundle sizes by ~40% and improved page load performance across applications– Modernized legacy modules into maintainable React/TypeScript codebase with ~90% test coverageAdditional Context (Auditdata)– Acted as informal technical owner for complex features across multiple modules– Participated in architectural decisions and system design discussions– Mentored developers and supported technical execution within the team
- NewGround LLC (Evolution Gaming)Javascript EngineerApril 2018 - March 2019 (11 months)Kyiv, Ukraine, 02000– Built high-performance UIs using React, TypeScript, Redux for live streaming environments– Developed modular components with Jest/Enzyme test coverage– Optimized Webpack build process, improving load times and animation performance
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Education
- Diplom-SpezialistMaikop State Technological University2005Studium in Holztechnologie mit Schwerpunkt auf technischen Prozessen, Produktionstechnologien und industrieller Automatisierung. Vermittelt wurden Grundlagen der technischen Mechanik, Konstruktion, Materialkunde, Qualitätsmanagement und Prozessoptimierung.
- Industrial and civil constructionBelgorod State Technological University2014Studium im Bereich Bauingenieurwesen (PГС) mit Schwerpunkt auf technischen Konstruktionen, Statik, Projektplanung, Werkstoffkunde und industriellen Prozessen. Vermittelt wurden analytisches Denken, technische Berechnungsmethoden, CAD-Grundlagen, Qualitätsmanagement sowie komplexe Projektorganisation.
Certifications
- Java-Entwickler – Abschluss eines zertifizierten TrainingsprogrammsGoIT – School of IT Professionals2012