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Oleksii R.

Oleksii R.

Full-Stack Developer

Verified expert

senior
Ukraine
$35/hour
English – Advanced
Ukrainian – Native
Top skills
Node.js React NestJS NextJS TypeScript PostgreSQL Docker MongoDB AWS LangChain
Oleksii R.
Full-Stack Developer

Verified expert

native
Ukraine
$35/hour
English – Advanced
Ukrainian – Native

Meet Oleksii ✨

A Full Stack Developer with 5.5 years of experience building scalable web applications using Node.js, TypeScript, and React across the entire development cycle from architecture selection to deployment. Oleksii writes clean, maintainable code with OOP principles, produces clear documentation, conducts code reviews, and covers code with unit tests, with a strong focus on system architecture and security best practices.

He has delivered production systems across SaaS, AI, cryptocurrency, and security domains. His projects include a smart lead generation platform for real estate professionals with automated outreach and AWS infrastructure, an AI-based desktop website builder with LangChain and OpenAI integrations and a cutting-edge SEO platform, an AI-powered algorithmic crypto trading system with KYC development and Web3 integration, and a two-factor authentication vendor-homeowner connection platform with payment gateway integrations.

Oleksii's core stack is Node.js with NestJS and Express on the backend and React with Next.js on the frontend, complemented by TypeScript throughout. He works confidently with PostgreSQL, MongoDB, Firebase, Docker, AWS, Azure, WebSockets, and modern testing tools including Cypress and Jest. He also brings experience with LangChain, OpenAI API, THREE.js, Electron, and Web3 integrations.

If you need a full stack developer who can own complex backend architecture, build polished frontend interfaces, and navigate AI integrations and blockchain environments with equal confidence, Oleksii is ready to deliver 🚀

Download the CV

Hard skills

JavaScript

TypeScript

Node.js

NestJS

Express.js

React.js

Next.js

Redux

Redux Toolkit

React Hook Forms

React Context

React Query

JSX

TSX

Material UI

Bootstrap

Tailwind CSS

THREE.js

Electron

Web3

LangChain

OpenAI API

Payment Gateway APIs

WebSocket

SQL

PostgreSQL

MySQL

Firebase

MongoDB

Docker

AWS

Azure

Nginx

Auth0

GitHub Actions

GitHub CI/CD

REST API Development

Software Architecture

Technical Documentation

TDD

FDD

Tools

Git

GitHub

GitLab

BitBucket

Postman

Unittest

Mock

Cypress

Jest

React Testing Library

WebStorm

JetBrains Products

Visual Studio

VS Code

Puppeteer

Fastify

Mailgun

Mapbox

Tracers

Shufti Pro

Soft skills

Communication

Responsibility

Perseverance

Problem solving

Team collaboration

Ownership

Attention to detail

Continuous learning

Smart Lead Generation Platform for Real Estate Professionals

Full Stack Developer
Duration:

1 year

Domains:
SaaS Real Estate
Project Description:

Developed full-stack features for a SaaS lead generation platform tailored to real estate professionals, integrating automated outreach tools and data sources. Enhanced system architecture, implemented new features, refactored backend code, integrated and maintained APIs, and supported AWS infrastructure and application deployment.

Tools & Technologies:

TypeScript, Node.js, NestJS, PostgreSQL, Fastify, Next.js, Material UI, Puppeteer, GitHub Actions, AWS, Mailgun, Payment Gateway API, Mapbox, Tracers

AI-Based Website Page Builder

Front-End Developer
Duration:

1.5 years

Domains:
Software Development AI SEO
Project Description:

Built the frontend for a desktop AI application that automatically generates responsive web pages from user-defined settings using LLMs and OpenAI integrations. Also developed frontend features for a companion SEO analytics platform with real-time performance insights and advanced optimization tools.

Tools & Technologies:

Next.js, React.js, Electron, Puppeteer, TypeScript, Tailwind CSS, Axios, Redux, Formik, LangChain, OpenAI API, WebSocket, Redis, Auth0, Payment Gateway API

Trading System

Full Stack Developer
Duration:

1 year

Domains:
Cryptocurrency AI
Project Description:

Built frontend and backend features for an AI-powered algorithmic trading system that automates decentralized market execution and replicates leading crypto portfolio strategies for fast, efficient transactions. Developed KYC verification flows, improved system architecture, and handled application deployment.

Tools & Technologies:

React.js, Node.js, Express.js, TypeScript, React Context, Axios, MongoDB, Web3, Blockchain, Shufti Pro

Platform for Connection Vendors with Homeowners

Full Stack Developer
Duration:

2 years

Domains:
Security
Project Description:

Built and maintained a full-stack platform designed to simplify two-factor authentication for team members connecting vendors with homeowners. Developed system architecture, implemented frontend and backend features, integrated payment gateway and third-party APIs, and maintained code quality through unit testing and code reviews.

Tools & Technologies:

Express.js, React.js, Node.js, React Context, Axios, Material UI, Payment Gateway API, Formik, Docker

Master's Degree in Computer Science

Sumy State University

Bachelor's Degree in Computer Science

Sumy State University

Deploy a Website with Azure Virtual Machines

Provider: Microsoft

Deploy a Website with Azure Virtual Machines

Provider: Microsoft

Full Stack Development

Provider: OktenWeb University, Lviv

Full Stack Development

Provider: OktenWeb University, Lviv

Getting Started with Azure

Provider: Coursera

Getting Started with Azure

Provider: Coursera
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