You will get Responsive React Next.js Frontend Development or Legacy UI Modernization
Rising Talent
Rising Talent
Project details
Is your web app laggy or losing users due to an outdated UI? A slow frontend kills conversions. Whether you need a modern React/Next.js app from scratch or want to migrate a legacy system, I deliver flawless, high-performance interfaces.
I am a Senior Engineer with 10+ YOE specializing in responsive UI and data-heavy applications.
WHAT I DELIVER:
• Legacy UI Modernization: Migrating outdated interfaces to React/Next.js.
• Performance Optimization: Blazing-fast loading and top Core Web Vitals.
• Complex Integrations: Connecting frontend states with secure backend APIs.
• Pixel-Perfect Responsive Design: Seamless layouts on all devices.
PROVEN TRACK RECORD:
• Optimized frontend core for a major European e-commerce platform.
• Migrated a massive legacy user interface to modern React.
• Built a seamless SaaS frontend handling heavy real-time marketplace data.
Let’s elevate your application. Choose your tier or message me for a custom quote!
I am a Senior Engineer with 10+ YOE specializing in responsive UI and data-heavy applications.
WHAT I DELIVER:
• Legacy UI Modernization: Migrating outdated interfaces to React/Next.js.
• Performance Optimization: Blazing-fast loading and top Core Web Vitals.
• Complex Integrations: Connecting frontend states with secure backend APIs.
• Pixel-Perfect Responsive Design: Seamless layouts on all devices.
PROVEN TRACK RECORD:
• Optimized frontend core for a major European e-commerce platform.
• Migrated a massive legacy user interface to modern React.
• Built a seamless SaaS frontend handling heavy real-time marketplace data.
Let’s elevate your application. Choose your tier or message me for a custom quote!
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$300
|
Standard
$750
|
Advanced
$1,600
|
|---|---|---|---|
| Delivery Time | 3 days | 7 days | 14 days |
Number of Revisions | 2 | 3 | 4 |
Number of Pages | 1 | 3 | 5 |
Design Customization | - | ||
Content Upload | - | - | |
Responsive Design | |||
Source Code |
Optional add-ons
You can add these on the next page.
Additional Revision
+$50
Additional Page
(+ 2 Days)
+$100Frequently asked questions
About OLEKSII
Senior Full Stack Developer | ReactJS | NestJS
Zaporizhia, Ukraine - 2:48 pm local time
Hi, I'm Oleksii. I am a Senior Full-Stack Engineer with 10+ years of hands-on experience architecturalizing, scaling, and optimizing heavy-traffic e-commerce ecosystems, custom ERPs, and automated marketplace workflows.
If you are struggling with legacy system migrations, sluggish data pipelines, or complex third-party API syncs, I am here to bridge the gap between heavy backend logic and pixel-perfect, responsive user interfaces.
What I bring to your project:
• Marketplace Mastery: Built and maintained systems synchronizing real-time data (prices, inventory, discounts) across Amazon, eBay, Walmart, Target, Allegro, and WooCommerce.
• High-Traffic Optimization: Proven track record optimizing data-heavy applications using Node.js, NestJS, and Elasticsearch, ensuring flawless uptime under high user loads.
• End-to-End Product Ownership: From legacy UI migrations (React/Next.js) to server administration, NGINX load balancing, and DevOps automation.
MY CORE TECH STACK:
• Frontend: React, Next.js, Redux, MobX, TypeScript, TailwindCSS, Ant Design, Material UI.
• Backend & DB: Node.js, NestJS, Express, TypeORM, Sequelize, MySQL, Redis, BullMQ, Elasticsearch.
• DevOps & Automation: AWS (CloudFormation, CloudWatch), Docker, NGINX, GitHub Actions, CI/CD.
Whether you need a full-lifecycle product built from scratch or a critical performance bottleneck fixed in your production environment - I deliver clean, maintainable, and business-driven code.
Click "Message" or "Invite" on the top right, and let’s hop on a brief discovery call to map out the solution for your project!
Steps for completing your project
After purchasing the project, send requirements so OLEKSII can start the project.
Delivery time starts when OLEKSII receives requirements from you.
OLEKSII works on your project following the steps below.
Revisions may occur after the delivery date.
Requirements Gather & Code Review
Reviewing your Figma design links, analyzing project requirements, or auditing the current repository codebase to map out the architecture.
Core Development & State Management
Writing clean, scalable React/TypeScript components, setting up robust state management, and integrating your backend REST/GraphQL APIs.