You will get a consultation on React Performance Audit
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⚠️ PLEASE MESSAGE ME TO DISCUSS YOUR PROJECT GOALS BEFORE PURCHASING.
If your application is slow or the codebase is hard to maintain, this is for you. I specialize in overhauling legacy systems, having optimized factory CRMs and POS systems for high performance. We will identify memory leaks, slow rendering components, and create a roadmap to migrate to React 18 and Next.js.
If your application is slow or the codebase is hard to maintain, this is for you. I specialize in overhauling legacy systems, having optimized factory CRMs and POS systems for high performance. We will identify memory leaks, slow rendering components, and create a roadmap to migrate to React 18 and Next.js.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
PSD to HTML, Performance Optimization, SecurityWhat's included $500
These options are included with the project scope.
$500
- Delivery Time 5 days
- Number of Revisions 0
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MH
Mable H.
Apr 8, 2024
Advanced JavaScript / React Engineer
JK
John K.
Mar 31, 2024
JavaScript React - Front-End Dev - For my startup - Long term
Kostiantyn is an awesome front-end dev. He worked very hard on my web-app demo project and had a great attitude. He is really committed to his work and highly skilled / knowledgeable. The demo is done and looks great - thank you! Would recommend
NV
Noman V.
Nov 30, 2023
Expert React Developer for Complex SPA
TC
Tara C.
Aug 16, 2023
Experienced Frontend Developer Needed
Kostiantyn was a great addition to our front-end team. We relied on him to execute all our tasks in a professional and swift manner, and the team found him to be a great team player.
We would definitely recommend him if you are looking to hire a front-end developer to handle all of your UI implementations. Thank you for a great time!
We would definitely recommend him if you are looking to hire a front-end developer to handle all of your UI implementations. Thank you for a great time!
EC
Eduard C.
Jul 6, 2021
Senior Front-End React Developer
About Kostiantyn
Frontend developer| React & Next.js Specialist for Complex Ecosystems
100%
Job Success
Vilniansk, Ukraine - 12:30 pm local time
I specialize in architecting robust Next.js platforms and React ecosystems using TypeScript, ensuring your product is fast, secure, and future-proof.
💡 Industry Expertise & Real-World Impact:
🔹 FinTech & Payments: Built secure financial interfaces and real-time SaaS platforms with complex workflows, integrating Stripe and Plaid from the ground up.
🔹 MedTech & Data Viz: Created advanced IVF report generators and dental CMS platforms, processing massive datasets into interactive charts and professional PDF reports.
🔹 InsurTech & Legal: Led technical teams in developing insurance arbitration ecosystems, focusing on modular architecture, security, and top-tier code quality.
🔹 Logistics & Travel: Improved UI/UX and performance for global car rental services, managing complex search and booking flows.
🔹 Enterprise Productivity: Engineered custom Atlassian extensions and sophisticated Kanban systems to streamline organizational workflows for large teams.
🔹 Industrial & Retail: Modernized legacy POS systems and factory CRMs with micro-services architecture, focusing on performance optimization and PWA features.
🛠 Comprehensive Tech Stack:
◎Frontend Architecture:
Core: React 18, Next.js (App & Pages Router), SPAs, PWAs
Languages: TypeScript, JavaScript (ES6+), i18n
State Management: Zustand, Redux (Saga, Thunk), MobX, Recoil, React Context
◎UI, Styling & Design:
Frameworks: Tailwind CSS, shadcn/ui, MaterialUI, Ant Design, Atlas-kit, Styled-components, SASS/SCSS, Less
◎Data Visualization & Charts:
Libraries: Recharts, Echarts, Victory Charts, BizCharts, react-chartjs-2
◎Infrastructure & Quality:
Backend/Integration: Node.js, GraphQL, REST APIs, Firebase
DevOps: Vercel, CI/CD pipelines, Webpack, npm, Docker
Testing & Tooling: Jest, Cypress, Enzyme, Testing-library, Zod, Husky, Sentry, Storybook
🤝 Why work with me?
I don’t just write code – I build products. Whether you need to launch a Next.js MVP in weeks or refactor a massive React enterprise system, I ensure the solution is clean, testable, and aligned with your business roadmap. My goal is to reduce your UI interaction paths and maximize application performance.
Ready to take your project to the next level? Let’s hop on a call to discuss your technical needs.
Steps for completing your project
After purchasing the project, send requirements so Kostiantyn can start the project.
Delivery time starts when Kostiantyn receives requirements from you.
Kostiantyn works on your project following the steps below.
Revisions may occur after the delivery date.
Performance Assessment
Identifying the "pain points" in your current user experience.
Code Quality Review
Checking for technical debt and outdated dependencies.