Hire the Best Ruby Developers & Programmers
in Ukraine

Over the past few years, I’ve been delivering full-stack web applications with a strong focus on clean architecture, maintainability, and performance. When working with me, you get a reliable technical partner who doesn't just write code, but cares about the overall product. What I bring to the table: 🔹 SOLID FOUNDATIONS: Well-structured architecture, clean code, and automated test coverage. 🔹 PROACTIVE APPROACH: I don't just complete tasks; I look for hidden performance issues, slow database queries, or outdated code, and suggest practical fixes before they become big problems. 🔹 END-TO-END EXECUTION: From backend logic and database design to frontend integration and deployment. If you're looking for a dependable engineer to help build or improve your product, feel free to send a message. I'm always open to discussing new technical challenges. Best, Sasha Stadnyk

Hi, I’m Zlata. I’m basically a typical American Software Engineer... just living in Ukraine now. And I always work in the EST timezone. I’ll write everything in any tech stack you have 😄 I’m a Software Engineer with 8+ years of experience as a Ruby on Rails developer, React developer, Node.js developer, Python developer, and .NET developer. I work with Ruby on Rails, React, Node.js, Python, .NET, PostgreSQL, Docker, AWS, JavaScript, TypeScript, API development, API integration, and SaaS software development. I help companies build and improve SaaS platforms, ERP systems, CRM tools, dashboards, marketplaces, internal systems, API products, and complex web applications using Ruby on Rails, React, Node.js, Python, and .NET. My focus is clean product logic, stable delivery, scalable architecture, and software that stays easy to maintain as the business grows. 📊 My Achievements in Numbers: 🔶 Ruby on Rails Developer for a Construction Application Platform ▪ Helped build a Ruby on Rails + React platform for managing construction applications, reviews, documents, and stakeholder workflows. ▪ Reduced application review time by 42%. ▪ Supported 18,500+ construction applications processed in the first year. ▪ Helped the product reach $1.4M ARR within 14 months. ▪ Worked with Ruby on Rails, React, PostgreSQL, Docker, AWS, S3, and API integration. 🔶 React Developer for a Construction Materials ERP SaaS ▪ Helped improve a complex ERP SaaS platform for concrete, aggregates, and asphalt producers. ▪ Improved sales, pricing, and operational workflows through better product logic and scalable software architecture. ▪ 98% of demo users became clients after product improvements. ▪ 91% of users rated the interface as clear and intuitive. ▪ The product later raised $3.4M. ▪ Focused on React, Ruby on Rails, SaaS workflows, API development, and complex web application structure. 🔶 Node.js Developer for an Aviation Maintenance SaaS ▪ Helped improve a complex aviation maintenance SaaS product used by field teams. ▪ 96% of demo users became clients after the product improvements. ▪ 97% of field users adopted the product after the first try. ▪ Reduced user errors by 41% and made onboarding 62% faster. ▪ Supported product logic, API integration, dashboards, and connected SaaS workflows using Node.js, React, Ruby on Rails, and API development. 🔶 Python Developer for an AI Healthcare SaaS ▪ Supported an AI-powered healthcare platform that grew from a chatbot into multiple AI agents for clinics and hospitals. ▪ The product raised $20M+. ▪ Helped support workflows that increased patient visits by 31%. ▪ Helped reduce call abandonment by 98%. ▪ Worked with Python, API integration, automation workflows, AI-related product logic, and scalable SaaS architecture. 🔶 .NET Developer for a Utility Billing Platform ▪ Helped improve utility billing workflows for a SaaS platform processing complex customer, billing, and reporting data. ▪ Helped process $14M+ in utility bills within 6 months. ▪ Reduced billing cycle time from 9 days to 1.5 days. ▪ Supported 96% client retention through better product stability and workflow clarity. ▪ Worked with .NET, React, API development, reporting logic, SaaS architecture, and reliable software delivery. Why should you hire me as a Software Engineer? ▪ 8+ years of experience with Ruby on Rails, React, Node.js, Python, .NET, JavaScript, TypeScript, PostgreSQL, API development, API integration, and SaaS software development. ▪ 120+ successful projects delivered across B2B SaaS, ERP, CRM, healthcare, construction, logistics, fintech, aviation, and internal business platforms. ▪ Strong experience with Ruby on Rails, React, Node.js, Python, and .NET for SaaS products, dashboards, admin panels, API-first platforms, integrations, automation, AI features, and enterprise systems. ▪ I use Claude, Cursor, GitHub Copilot, and ChatGPT to speed up research, debugging, refactoring, and delivery. ▪ I work well with founders, CTOs, product managers, and teams that need clear communication across Ruby on Rails, React, Node.js, Python, and .NET products. What I can help you with: ✔️ Build or improve Ruby on Rails SaaS products ✔️ Create React dashboards, portals, admin panels, and SaaS interfaces ✔️ Build Node.js services and API integrations ✔️ Support Python automation, data workflows, and product logic ✔️ Work with .NET systems and connected software platforms ✔️ Build API-first products with Ruby on Rails, React, Node.js, Python, .NET, PostgreSQL, Docker, and AWS ✔️ Improve performance, stability, and maintainability of existing Ruby on Rails, React, Node.js, Python, and .NET applications ✔️ Support SaaS, ERP, CRM, fintech, healthcare, logistics, construction, and internal tools Need help with Ruby on Rails, React, Node.js, Python, .NET, API development, or SaaS development? Message me and let’s discuss your product. 📩🤝

I am a Senior Fullstack Developer with over 15 years of hands-on experience in building and scaling Java , C# / Net , Angular applications for startups, enterprises, and SaaS platforms. Currently, I’m working as the Chief Technology Officer at InventorSoft, a software development agency specializing in web and mobile solutions. I bring a strategic mix of technical depth, team leadership, and product vision to every project. Why hire me🧐: 📌 Expert in Scalable Java and .Net Architectures - Over 15 years of experience in developing Java, .Net, C#, Angular scalable applications from different domains. - Backend systems built with Spring Boot (15+ years) – Delivered scalable microservices and high-performance business logic for enterprise-grade applications. - ORM & data access with Hibernate – Applied advanced ORM techniques for efficient database interactions, query optimization, and data integrity in distributed systems. - Frontend development with Angular & Thymeleaf Designed and delivered 200+ robust backend systems for SaaS products, e-commerce platforms, and enterprise clients. 📌 Cloud-Native Platform Engineering Specializes in building secure, scalable, cloud-native platforms using leading cloud providers: - 8+ years of production experience with AWS – Deployed scalable, secure, and high-availability applications. - 9+ years of hands-on Azure expertise – Delivered enterprise-grade solutions with Azure App Services, Azure DevOps, and SQL/Azure Storage. - 5+ years of experience on Google Cloud Platform (GCP) – Built and deployed containerized microservices using GKE, Cloud Run, and Firebase. 📌 API-First & Cloud-Native System Design - Strong background in API integration and microservice architecture. - Created high-performance APIs for platforms serving 50K+ users, ensuring seamless third-party integration and scalability. - Experienced in Docker & Kubernetes, enabling CI/CD pipelines and resilient containerized systems. 📌 Full-Stack Leadership & Agile Team Management - Led and mentored teams of 5–25 developers through all stages of the SDLC—requirements gathering to deployment and maintenance. - Specialized in building cross-functional teams for backend-heavy systems, modern UIs (React, Angular, Thymeleaf), and DevOps automation. My latest achievement as a Software Architect: 🤝 Partnered with 45+ SaaS companies to design and deliver secure, scalable platforms using Spring Boot, AWS, and modern cloud services. 🚀 Helped 10 tech startups scale from MVP to production—selecting the right tech stack, defining cloud-native architecture, and assembling strong dev teams. 💼 Enabled 5 client acquisitions through the development of enterprise-grade software that attracted major buyers and investors. 🏭 Led a digital transformation project for a multi-billion-dollar oil company, delivering a secure, API-first platform that automated mission-critical operations. 🧩 Technologies I Specialize In - Languages/Frameworks: Java, C#, .Net, Spring Boot, Hibernate, Thymeleaf, .Net Core - Cloud Platforms: AWS (8+ years), Azure (9+ years), Google Cloud (5+ years) - DevOps Tools: Docker (7+ years), Kubernetes (5+ years) - Integration & Architecture: RESTful API integration, microservices, clean architecture, CI/CD pipelines Clients that I am proud of: 💻 Shoeby – A fashion retail platform focused on modernizing the e-commerce experience with intuitive UI, product personalization, and seamless shopping journeys. 💻 CellRebel – Provides advanced mobile network analytics, helping telecom companies improve coverage and performance based on real user data. 💻 Blade – A technology-powered aviation company offering urban air mobility services, including helicopter and seaplane flights. 💻 Matics – A real-time operational intelligence system for manufacturers, offering production insights and process optimization across the factory. 💻 MedischeScholing – A medical e-learning platform that enables healthcare professionals to access, register for, and track accredited training and certifications. ➡️ Learn more about other projects on the InventorSoft portfolio Keywords: Java, Backend, Developer, Fullstack, Web, Cross-Platform, Mobile, Application, AI, OpenAI, Service, App, Development, Engineer, Integration, Build, Website, Expert, Spring boot, MySQL, Development Team, Integrated, SaaS Platform, remote, Full-stack, Senior, Software, Client Management, GraphQL, API, .NET, Asp.net, Programmer, Technical Lead, Dashboard, MVC, Developers, ASP.NET, AspNetZero, core, software, MAUI, C#, Angular, .Net, Core, Principal, Performance, Scalability, Microsoft, Blazor, SQL, Server, Frontend, React, Ruby on Rails, RoR/React, front-end, Tailwind, feature, TailwindCSS, Technical Staff, JavaScript, ROR

With over 13 years of experience and 14,000+ hours on Upwork, I create Ruby on Rails web applications that are not only functional but built to last. Able to take a project at any stage — from an initial idea to a complex, production-ready system — and manage every aspect: backend architecture, integrations, performance optimization, and long-term maintenance. I have successfully delivered large-scale projects across multiple domains — from a hotel booking engine to a fintech platform for investors, a job search and recruitment platform and many others. I leverage modern tools such as GitHub Copilot for documentation, autocomplete, code optimization, and SQL query improvements, while using AI assistants like ChatGPT and Gemini to speed up research and handle small tasks such as generating regular expressions. I also understand the importance of AI in boosting development speed, productivity, and automation, and apply it thoughtfully to enhance my workflow without compromising code quality. Whether you need to launch a new product, rescue a struggling codebase, or scale your existing platform, I bring the skills, reliability, and insight to get it done right the first time.

I have more than 12 years of experience in web development, and 11 of them I dedicated to RoR. I'm an easy learner and I like a challenge, that's why I'm willing to work hard and produce high-quality code. I'm here to work on exciting projects and to apply my skills to bring your brilliant idea to life. I can work both on the long-term and short-term projects, as long as they are interesting :)

I'm Ruby on Rails developer with 2 years of commercial experience. Previously I worked on e-commerce project thedelisociety.com from scratch to production with real clients. It was monolith ROR project + Javascript (we used Stimulus). Second big project was about tracking vehicles. It was ROR + React project with Grape API