Ivan K.

Full Stack Developer | SaaS Platform | React TypeScript

Need a full-stack product built fast without sacrificing scalability? With 15 years as a Full-Stack Developer and AI Engineer, I’ve delivered 16k+ hours and $1M+ earnings across web and mobile products. For startups and SaaS teams, I build React, Next.js, Node.js, and Flutter solutions that launch cleanly and scale confidently. 🎯 HOW I CAN HELP YOU FULL-STACK WEB APPLICATION DEVELOPMENT Launch scalable web products that convert users faster and support long-term growth. I build React, Next.js, Node.js, and TypeScript applications with architecture choices that have supported $1M+ in Upwork earnings and 100% Job Success. AI AGENT AND OPENAI INTEGRATION Add intelligent features that automate work, reduce manual effort, and create new product value. I integrate OpenAI APIs and AI workflows into existing platforms to accelerate delivery and turn ideas into usable AI-powered products. MOBILE APP DEVELOPMENT Ship iOS and Android apps that give users a smooth experience across devices and help you reach more customers. I develop with Flutter, React Native, Swift, and Kotlin, with proven experience delivering apps published to both Apple and Google app stores. SAAS PLATFORM DEVELOPMENT Turn complex ideas into secure, scalable SaaS products that are ready to monetize. I have built multi-tenant platforms with authentication, billing, APIs, and dashboards for startups and enterprise teams in as little as MVP timelines. API AND BACKEND ENGINEERING Increase system stability, speed up integrations, and support growth with robust backend foundations. I design Node.js, NestJS, Express, PostgreSQL, and cloud-based systems that handle real-world product demands across web, mobile, and AI features. 🏆 RESULTS "Thanks to Cinnamon's efforts, the app's server response times were excellent, and the end client was thrilled with the results. The team was responsive and pragmatic in responding to needs, communicating via virtual meetings, emails, and messages. Their talented engineering team was impressive." – Gregory W., Founder, Mojave Interactive LLC "Thanks to Cinnamon's work, the client has seen a 25% higher completion rate and 40% less completion time. The pricing calculators have reduced the error rates by 50%. The team delivers timely items, responds quickly to messages, and addresses requests effectively. Their support is unique." – Premnath M., Head of Software Development Digital Bank, BAWAG AG "The Android app has thousands of downloads and impressive online ratings, which reflects Cinnamon Agency's technical expertise. The team is willing to work long hours to meet deadlines. They excel at project management and have a robust reporting system in place." – Garin Toren., Founder, Ping 🎖 JavaScript Algorithms and Data Structures Certification 🎖 React Developer Certification 🎖 AI Engineering and LLM Integration Certification See full case studies in my portfolio below. 🤝 𝗚𝗘𝗧 𝗜𝗡 𝗧𝗢𝗨𝗖𝗛 Have an app idea or product to launch? Message me on Upwork today for a free consultation and a clear plan to move forward. I typically respond within 4 hours and can offer quick turnaround for urgent projects. 𝗛𝗼𝘄 𝗜 𝗪𝗼𝗿𝗸 I build in React, Next.js, and TypeScript to ship fast, maintainable web apps, then use Node.js, PostgreSQL, and AWS to keep the backend reliable and scalable. For AI features, I integrate OpenAI APIs and Cursor into workflows that automate tasks and add real product value. I also use Flutter when a project needs a polished cross-platform mobile app. I build full-stack web applications with React and Next.js, integrate Node.js APIs, and deliver mobile app development with Flutter and AI development that scales.