Oleksandr S.

🏆 Senior Full-Stack Engineer | AI SaaS • AI Agents • RAG • Next.js | $200K+ Earned · 100% JSS

I build AI-powered SaaS products that are ready for real users, real data and real growth. From MVP architecture and full-stack development to AI Agents, RAG and production deployment, I can own the technical side of a product end-to-end.

My core stack is Next.js, React, TypeScript, Node.js, Python, FastAPI, Supabase and PostgreSQL, with OpenAI and Claude for production AI features. I also build React Native mobile applications when mobile is part of the product ecosystem.

PROBLEMS I SOLVE
Most clients come to me with one of these:
❌ An AI or SaaS MVP that works in a demo but isn't ready for production.
❌ A product that needs AI Agents, RAG or LLM features integrated into existing workflows.
❌ An existing SaaS platform that's becoming slow, difficult to maintain or expensive to extend.
❌ No clear technical architecture for moving from MVP to a scalable product.
❌ A FinTech or data-heavy product where security, integrations and reliable infrastructure matter.
❌ A web product that also needs a React Native mobile experience without maintaining completely separate systems.

I approach these as product engineering problems, not isolated development tasks. Architecture, data models, APIs, AI infrastructure and deployment decisions are made with the next stage of the product in mind.
150+ shipped projects. 20+ countries. Zero rebuilds requested.
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WHAT YOU GET

🔷 AI-Powered SaaS Product Engineering
I build SaaS MVPs and production platforms using Next.js, React, TypeScript, Node.js, Python, FastAPI, Supabase and PostgreSQL. This includes product architecture, authentication, subscriptions, payments, dashboards, APIs, third-party integrations and infrastructure.

🔷 AI Agents, RAG & LLM Integration
I build AI Agents, agentic workflows, Retrieval Augmented Generation (RAG), semantic search, function calling and LLM-powered product features using OpenAI API, Claude API, LangChain and LangGraph.
The goal is to make AI part of the actual product workflow, not a separate chatbot or proof of concept.

🔷 FinTech & Data-Heavy Products
I work with FinTech SaaS, financial dashboards, analytics platforms and products with complex data flows. This includes payment integrations, subscription systems, role-based access, data processing and backend architecture designed around reliability and maintainability.