Oleh T.

Your SaaS or AI product needs more than a working demo. I turn fast-built, inherited, and AI-assisted applications into stable production systems across UI, APIs, databases, AI integrations, and deployment. 📦 Multi-tenant booking SaaS 🎓 EdTech platform that increased sales by 190% 📱 React Native applications shipped to both app stores ⚙️ React · Node.js · PHP/Laravel · Next.js · NestJS · Python · WordPress AI, Full-Stack & SaaS Development I work as an AI Developer, Full Stack Developer, and SaaS Developer, building complete applications from the frontend through the backend and infrastructure. I can help you: • Build an AI-powered SaaS product or MVP • Add OpenAI API and LLM features to an existing application • Develop AI assistants, intelligent search, RAG, and document workflows • Take over and stabilize an inherited or AI-generated codebase • Build React and Next.js interfaces • Develop Node.js, NestJS, and PHP/Laravel APIs • Design multi-tenant SaaS architecture • Implement subscriptions, Stripe billing, permissions, and user roles • Improve application performance, security, and reliability • Prepare an application for production deployment and growth AI Developer & AI Integration As an AI Developer, I integrate practical AI functionality into real products, not isolated demonstrations. My AI development work includes OpenAI API integration, LLM-powered assistants, RAG workflows, embeddings, intelligent document processing, automated content and data workflows, API-connected AI features, and AI-powered SaaS applications. I focus on the production concerns around AI integration: response quality, permissions, error handling, logging, latency, API costs, data flow, and maintainability. Full Stack Developer As a Full Stack Developer, I take responsibility for the complete vertical slice: • Frontend architecture and responsive UI • Backend services and API development • Database architecture and query optimization • Authentication and role-based access control • Third-party API and payment integrations • Background jobs and workflow automation • Testing, deployment, monitoring, and maintenance My primary stack includes React, Next.js, Vue.js, Node.js, NestJS, PHP, Laravel, Python, FastAPI, MySQL, PostgreSQL, Redis, REST APIs, and Docker. I also work as a React Developer, Node.js Developer, PHP/Laravel Developer, and React Native Mobile App Developer when a project requires deeper specialization. SaaS Developer As a SaaS Developer, I understand that building features is only part of the job. A SaaS product also needs reliable tenant isolation, permissions, billing, integrations, observability, and an architecture that can grow with the business. My SaaS development experience includes: • Multi-tenant SaaS platforms • Subscription and Stripe billing systems • User roles, permissions, and account management • Admin dashboards and internal business portals • CRM and third-party API integrations • Analytics and reporting systems • Performance optimization and scalability • Codebase audits, application rescue, and production launches Selected Project Experience 📦 Multi-Tenant Booking SaaS Led full-stack and SaaS development for a European self-storage platform using React, Node.js, PHP/Laravel, databases, payment integrations, and operational automation. The platform grew to more than 170 monthly reservations and helped triple signed contracts. 🎓 EdTech Matching Platform Built interconnected Laravel applications with a React frontend, matching workflows, dashboards, and business automation. The resulting SaaS platform contributed to 190% year-over-year sales growth. 📊 Analytics & AI SaaS Developed data-intensive services using Python, FastAPI, React, Node.js, PostgreSQL, Redis, external APIs, and AI integrations. 📱 React Native Applications Built and shipped React Native applications for iOS and Android, supported by production APIs, authentication, real-time features, maps, notifications, and administrative systems. Codebase Takeover & Application Rescue Already have an application that is almost ready but difficult to launch? I can inspect the architecture, identify the highest-risk problems, stabilize the codebase, repair integrations, improve performance, and create a practical path to production. This is especially useful for inherited projects, rapidly built MVPs, AI-assisted codebases, and SaaS products that have outgrown their original architecture. Core roles: AI Developer · Full Stack Developer · SaaS Developer · React Developer · Node.js Developer · PHP/Laravel Developer · React Native Developer If you need one developer who can understand the whole product - AI features, UI, APIs, databases, SaaS architecture, and deployment - send me your current application, requirements, or technical problem. I’ll help you determine the clearest path forward