About Serhii
I'm a Full Stack Engineer and Tech Lead with 12 years of experience. I've built and shipped 6+ SaaS products end-to-end, from backend APIs and microservices to React frontends and React Native mobile apps.
My core stack is Python, React.js, TypeScript, Node.js, NestJS and FastAPI.
I'm comfortable with AWS, GCP, Docker, PostgreSQL, MongoDB and Kafka.
Recently, I've been working extensively with the OpenAI API, LLM integrations, and multi-agent systems for enterprise automation.
I can lead a team or work independently, I've managed engineers, handled architecture decisions, sprint planning and code reviews.
Past projects span fintech, adtech, healthtech, and AI-driven platforms.
If you need someone who can take ownership and deliver, I'm your person.
Ukrainian
Native or bilingual
English
Fluent
Polish
Conversational
Russian
Native or bilingual
Can work on-site
Krakow (up to 50km)
Experience
- ValooniaTech LeadDIGITAL AND ITAugust 2025 - Today (11 months)Led a team of 4 to build and ship a production-ready image-to stencil platform using ComfyUI for AI generationBuilt the backend on Flask and GCP, integrated ComfyUI pipelines for on-demand stencil generation from user photosReached 3000+ active customers within 2 months of production release
- Team Work Spirit (TWS)Senior Software Engineer | Technical LeadDIGITAL AND ITFebruary 2021 - August 2025 (4 years and 6 months)Was responsible for leading engineering teams and delivering full-stack solutions across multiple SaaS products.Built a multi-tenant SaaS platform for processing large volumes of marketing data with OpenAI API integration for intelligent agency matching.Developed a multi-agent automation system for an enterprise CRM platform using Kafka-based event pipelines and optimized database queries to reduce latency.Served as Head of Engineering on a VC management platform, managing a team of 4 and handling architecture decisions.Built real-time features using React Native, WebSockets, and a Golang backend handling up to 100,000 simultaneous connections.
- GVO Company, Inc.Full-stack Developer | PHP Integration Tech LeadDIGITAL AND ITJune 2014 - February 2021 (6 years and 8 months)Worked on PHP integration architecture and cross-system API developmentDeveloped and maintained full-stack web applications across multiple product linesMentored junior developers and drove adoption of coding standards and best practices
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Education
- Bachelor's degree InformationKharkiv National University of Radio Electronics2008Information Security