Andrii S.

🚀 Senior React Developer | Next.js Developer | Full Stack Developer | 12+ Years Experience 🏆 $100K+ Earned on Upwork | 100% Job Success | 90 Jobs Completed | 3,040 Hours Looking for an experienced React Developer, Next.js Developer, or Full Stack Developer who can take ownership of your project and deliver production-ready solutions? I'm a Senior React Developer and Team Lead with 12+ years of commercial experience building scalable SaaS platforms, complex web applications, dashboards, and business management systems. My core expertise is React.js, Next.js, TypeScript, JavaScript, and Node.js. As a Full Stack Developer, I also have experience with ASP.NET, C#, PHP, Laravel, PostgreSQL, and MySQL. I don't just build interfaces. I help businesses solve complex problems, design maintainable architectures, improve performance, and turn ideas into reliable software. 🏆 WHY CLIENTS CHOOSE ME ✅ $100K+ earned on Upwork with 100% Job Success ✅ 90 completed jobs and 3,040 working hours ✅ 12+ years of professional software development ✅ Senior React Developer with Team Lead experience ✅ Strong frontend architecture and performance optimization skills ✅ Full Stack Developer with backend and database experience ✅ Experience with startups, SaaS products, and enterprise applications ✅ Clear communication, code quality, and long-term project ownership 🚀 WHAT I CAN BUILD FOR YOU As a React Developer, Next.js Developer, and Full Stack Developer, I specialize in: 🔹 SaaS Platforms & Startup MVPs — scalable applications built for long-term growth 🔹 React.js & Next.js Applications — modern, responsive, high-performance web solutions 🔹 Admin Panels & Dashboards — advanced tables, analytics, charts, and reporting 🔹 CRM & Business Management Systems — custom workflows and internal business tools 🔹 Financial & Analytics Platforms — forecasting, financial data, and interactive visualizations 🔹 Scheduling & Booking Systems — complex calendars, resource management, and dispatching 🔹 Real-Time Applications — live updates, notifications, and data synchronization 🔹 API Development & Integration — REST APIs, GraphQL, Node.js, ASP.NET, and third-party services 🔹 Performance Optimization — React rendering optimization, virtualization, and code refactoring 🔹 Full Stack Web Applications — frontend, backend, databases, authentication, and cloud storage ⚙️ TECHNICAL EXPERTISE Frontend: React.js • Next.js • TypeScript • JavaScript • HTML5 • CSS3 • SASS • Tailwind CSS • Bootstrap React Ecosystem: Redux • React Redux • Redux Thunk • React Hook Form • Formik • Easy Peasy • React Apollo • GraphQL Backend & Full Stack: Node.js • Express.js • ASP.NET • C# • PHP • Laravel • REST APIs Databases & Cloud: PostgreSQL • MySQL • Microsoft SQL Server • AWS S3 UI & Data Visualization: Ant Design • React Bootstrap • Semantic UI • Syncfusion • Recharts • Nivo • D3.js • Three.js • SVG • Canvas • React Virtualized Tools & Integrations: Stripe • SignalR • Server-Sent Events • MSAL • Git • Jest • Axios • i18next 🤝 WHY WORK WITH ME? ✔ I take ownership of projects and focus on business results. ✔ I write clean, reusable, maintainable React and TypeScript code. ✔ I understand both frontend and backend development. ✔ I can contribute to architecture and technical decisions. ✔ I communicate clearly and collaborate effectively with teams. ✔ I prioritize performance, usability, and long-term maintainability. 🔥 REAL PROJECT EXPERIENCE 🏦 Financial SaaS & Equity Management As a React Developer, I built scalable React.js and TypeScript interfaces for cap tables, shareholder records, stock options, and investment workflows. Created reusable components and integrated ASP.NET APIs. 🚛 Construction Management & Scheduling As a React Developer, I delivered scheduling, dispatching, and operator management tools. Built interactive calendars, dashboards, and real-time features with React.js, TypeScript, SignalR, and Syncfusion; contributed to a Cordova mobile app. 📊 Sales Forecasting & Analytics As a React Developer, I built data-heavy dashboards, CRM-connected forecasting tools, and custom charts with React.js, Redux, Recharts, SVG, and Canvas. Optimized thousands of records with React Virtualized and integrated Stripe. 🚗 3D Digital Marketplace As a React Developer, I built responsive marketplace interfaces with Redux and Three.js 3D car visualizations. Added live updates through Server-Sent Events for cryptocurrency-enabled digital collectibles. 🚀 LET'S WORK TOGETHER! Whether you need a React Developer to build a modern web application, a Next.js Developer for your next project, or a Full Stack Developer to develop a complete SaaS platform, I'd be happy to help. With 12+ years of development experience and a proven Upwork track record, I can help you turn your ideas into scalable, production-ready applications.