You will get debug, fix, and improve your React / Next.js app performance
Project details
I’m a Frontend React Engineer, Frontend Lead, and Senior Software Engineer with over 3 years of experience delivering high-quality web applications for companies such as ChessAt3, Jua.AI, and Found.ee.
As a Rising Talent on Upwork, I specialize in building scalable, robust, and efficient applications using modern technologies and frameworks, including React.js, Next.js, TypeScript, and JavaScript.
I’ve worked on a wide range of web projects — from SaaS platforms and enterprise web apps to custom websites — helping clients turn their ideas into clean, optimized, and user-focused digital solutions.
Before diving into development, I make sure your project has a solid foundation. My discovery and analysis process includes:
Gathering and validating requirements
Conducting a technical feasibility assessment
Outlining a clear project scope and roadmap
With deep expertise in React and Next.js, I’m confident in delivering efficient, modern, and high-performing solutions tailored to your business needs.
📩 Please message me before placing an order — I’ll be happy to review your project and suggest the best approach.
As a Rising Talent on Upwork, I specialize in building scalable, robust, and efficient applications using modern technologies and frameworks, including React.js, Next.js, TypeScript, and JavaScript.
I’ve worked on a wide range of web projects — from SaaS platforms and enterprise web apps to custom websites — helping clients turn their ideas into clean, optimized, and user-focused digital solutions.
Before diving into development, I make sure your project has a solid foundation. My discovery and analysis process includes:
Gathering and validating requirements
Conducting a technical feasibility assessment
Outlining a clear project scope and roadmap
With deep expertise in React and Next.js, I’m confident in delivering efficient, modern, and high-performing solutions tailored to your business needs.
📩 Please message me before placing an order — I’ll be happy to review your project and suggest the best approach.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$800
|
Standard
$1,200
|
Advanced
$1,500
|
|---|---|---|---|
| Delivery Time | 2 days | 5 days | 10 days |
Number of Revisions | 1 | 3 | 5 |
Bug Investigation | - | ||
Fix Documentation | - | ||
Detailed Code Comments | - |
About Oleg
React Full-Stack JavaScript Developer | Next.js, Node.js, Nest.js
Lviv, Ukraine - 5:47 am local time
Transforming Ideas into High-Performance Digital Products 🚀
I help startups and product companies build fast, scalable, and user-focused web and mobile applications that drive measurable business results.
👋 About Me
Hi, I’m Oleg Bandrivskiy, a Fullstack React / React Native Developer with 4+ years of hands-on commercial experience building production-ready apps for international companies.
I specialize in React.js, Next.js, TypeScript, and React Native, Node.js, Express.js delivering modern, high-performing, and maintainable applications for web and mobile.
My work blends clean architecture, smooth UI/UX, and real-world scalability — ensuring every line of code contributes to business growth.
🧠 Experience & Highlights
🌍 Jua.ai — React & Next.js Developer
Refreshed and modernized the UI for an AI-driven weather intelligence platform.
Redesigned major product interfaces, optimized frontend architecture, and boosted overall performance and visual consistency using React, Next.js, and TypeScript.
♟ ChessAt3 — React & Next.js Developer
Built a complex admin management system for an educational platform.
Developed real-time dashboards, advanced filters, and data sync features, significantly improving scalability, maintainability, and UX quality.
These projects showcase my ability to deliver pixel-perfect design, advanced state management, and seamless frontend performance in production environments.
⚙️ Technical Expertise
✅ Languages: TypeScript, JavaScript (ES6+), Node.js, Python,
✅ Frontend: React.js, Next.js, React Native, Expo
✅ State Management: Redux, Zustand, React Query, Redux-Saga, Context API
✅ Styling: Tailwind CSS, Styled Components, Material-UI, Ant Design, Radix UI
✅ Backend & Cloud: Firebase, Supabase, REST APIs, CI/CD, Node.js, Express.js, Django
✅ Testing: Jest, React Testing Library, Cypress
✅ Design Tools: Figma, Storybook, Atomic Design
🏆 Why Clients Choose Me
🔹 High-level quality with startup speed — balancing scalability and fast delivery
🔹 Cross-platform expertise — React Native for iOS & Android
🔹 Strong product mindset — I don’t just code features, I build user experiences
🔹 End-to-end ownership — from architecture to deployment
🔹 Transparent communication — proactive updates and reliable collaboration
💼 What I Deliver
📱 High-performance, mobile-friendly React/Next.js apps
🧩 Clean, modular, and reusable codebase
🎨 Pixel-perfect UI from Figma
🚀 Fast iteration, performance optimization, and long-term maintainability
🛠 Modern development practices — CI/CD, Git workflows, agile sprints
💬 Let’s Build Something Great Together
Whether you need a React/Next.js engineer for a SaaS MVP, a React Native expert for mobile, or a dedicated developer to lead your frontend, I can help you ship faster, scale smarter, and deliver value that lasts.
📞 Let’s connect and discuss your next project — I offer a short discovery call to understand your goals and suggest the best approach.
Keywords: React.js Specialist, Flutter Expert, Expert Full Stack Developer, Full Stack Web Developer, Swift Developer, React Native Expert, React.js Developer, Full stack Software Developer, Expert API Developer, Senior Backend Developer, Cross-Platform App Developer, Mobile App Developer, Node.js Expert Developer, Full Stack Development Specialist, Full Stack Software Engineer, React Engineer, React Development Expert, Senior iOS Developer, Kotlin Specialist, Backend Developer, Mobile App Development Specialist, Senior Mobile App Developer, Expert React Developer, Senior Full Stack Engineer, Senior Full-Stack Engineer, Experienced Frontend Developer, React Development Specialist, Full Stack Developer, Experienced React Developer, Software Development Specialist, Experienced React Developer, Senior Node.js Developer, Expert Frontend Developer, Frontend Developer, Next.js Expert, iOS Swift Developer, Senior Web & Mobile App Developer
Steps for completing your project
After purchasing the project, send requirements so Oleg can start the project.
Delivery time starts when Oleg receives requirements from you.
Oleg works on your project following the steps below.
Revisions may occur after the delivery date.
Step 1 🪲 Bug Analysis & Reproduction
I will review the provided source code, reproduce the reported issue(s), and identify their root cause to ensure an accurate fix.
Step 2 🛠 Fix Implementation & Testing
I will apply code fixes, test them across different environments, and ensure the issue is fully resolved without affecting other parts of the app.