Serhii O.

I’m a Full Stack Web Developer specializing in React, Next.js, Node.js, MERN stack development, SaaS platforms, AI integrations, and scalable API-driven web applications. I build fast, secure, production-ready systems with clean architecture and long-term scalability for startups and growing businesses. With 10+ years of experience in web development and 5+ years focused on modern full stack ecosystems, I deliver end-to-end solutions including frontend, backend, databases, authentication, payment systems (Stripe), real-time applications (Supabase/WebSockets), and enterprise SaaS platforms. Experience with Next.js, e-commerce platforms, API development, authentication systems, payment integration, database architecture and deployment. 💻 Core Expertise (Full Stack + SaaS + MERN) As a full stack web developer, I build: SaaS platforms and multi-tenant architectures E-commerce systems with Stripe payment integration Booking, scheduling, and marketplace platforms Admin dashboards, CRM systems, and analytics tools Real-time applications using Supabase and WebSockets API-driven architectures and microservices Scalable MERN stack applications (MongoDB, Express, React, Node.js) I specialize in Next.js development, React development, Node.js backend systems, API integration, authentication systems, and scalable database design. ⚙️ Backend Engineering | Node.js, Express, NestJS As a backend-focused full stack developer, I design secure, high-performance systems using Node.js, Express, and NestJS. I build: REST API development & API integration Authentication & role-based access control Stripe payment systems for SaaS & e-commerce Database architecture (MongoDB, MySQL, PostgreSQL, Supabase, Firebase) Real-time backend systems (WebSockets, Supabase) Third-party API integrations (CRMs, AI tools, automation systems) 🎨 Frontend Development | React, Next.js, Redux As a front-end web developer, I build modern, fast, and scalable UI systems using React, Next.js, Redux, and TailwindCSS. I create: High-performance SaaS dashboards SEO-optimized Next.js applications Responsive UI/UX interfaces Redux-based state management systems Real-time frontend integrations with APIs 🤖 AI Development & Automation (Cursor + Claude Code) I integrate modern AI tools like Cursor and Claude Code to accelerate development and build intelligent systems. I deliver: AI chatbots and assistants AI-powered SaaS features Automation workflows OpenAI / API integrations Smart backend logic & data processing systems ☁️ Databases, Supabase & Firebase Strong experience in: Supabase (auth, real-time DB, APIs) Firebase (real-time apps, cloud functions) MongoDB, MySQL, PostgreSQL Database optimization & scalable architecture SaaS-level data modeling 🛒 SaaS, E-commerce & Enterprise Systems I build: Subscription-based SaaS platforms E-commerce platforms with Stripe integration Booking & marketplace systems Enterprise dashboards & admin systems Large-scale full stack applications 📱 Additional Experience React Native developer (mobile apps) Python developer (automation & backend tools) WordPress developer (custom websites) Cross-platform mobile development 💬 Why Clients Choose Me ✔ Top-tier MERN stack expertise ✔ Full stack web developer (frontend + backend mastery) ✔ SaaS architecture & scalable system design ✔ Strong API development & integration skills ✔ AI integration & automation workflows ✔ Clean, maintainable, production-ready code ✔ Reliable communication & fast delivery 🚀 Let’s Build Something Scalable If you’re looking for a Top Full Stack Web Developer to build scalable SaaS platforms, modern web applications, or AI-powered systems, I can help you turn your idea into a production-ready product with clean architecture and long-term scalability.