Олександр

Oleksandr Kislyi
React / Next.js Developer · React Native / Expo Developer
Ukraine · Remote
Email: [open contact info](look above in the "contact info" section)
Telegram: @akisly
linkedIn: @akisliy

Professional Summary
Frontend and mobile developer with commercial experience since 2020,
specializing in React, Next.js, React Native, and Expo. Experienced in taking
features from requirements and architecture decisions through implementation,
release, and ongoing support. Skilled in building production web and mobile
applications, integrating REST APIs and real-time functionality, conducting
code reviews, and mentoring junior developers. Hands-on experience with App
Store and Google Play releases. Comfortable working independently and
collaborating with cross-functional teams.

Work Experience
Onix-Systems
React & React Native Developer
May 2020 — Present
Contributed to the development and launch of five production web and
mobile products across subscription services, healthcare, land and real
estate, and internal enterprise systems.
Participated in the publication and ongoing support of three mobile
applications released through the App Store and Google Play.
Built applications from scratch and developed new functionality for existing
products, taking features from estimation and architecture decisions
through implementation, release, and maintenance.

Oleksandr Kislyi 1

Implemented authentication, subscription, and other complex user flows,
integrated REST APIs, and converted Figma designs into responsive
production-ready interfaces.
Modernized legacy applications and rewrote large frontend modules to
improve maintainability and support further product development.
Investigated and resolved production issues, conducted code reviews, and
supported junior developers.
Worked in cross-functional teams of 4–6 specialists, including backend
developers, designers, QA engineers, and project managers.
Worked as the sole frontend or mobile developer on selected projects,
taking responsibility for architecture, planning, implementation, releases,
and ongoing support.
Technologies: React, Next.js, React Native, Expo, TypeScript, JavaScript,
Redux Toolkit, RTK Query, TanStack Query, Zustand, React Hook Form, Zod,
GraphQL, REST APIs, WebSocket, Socket.IO, Supabase, Firebase, Tailwind
CSS, shadcn/ui, Playwright, Vitest, Git, GitHub Actions.
Development tools: Claude Code, Codex, MCP.

Portfolio
Detailed project case studies:
Land Portal
Avela Health
Enterprise Operations Management Platform
GoProceed

Education
Volodymyr Vynnychenko Central Ukrainian State Pedagogical
University
Master’s Degree in Computer Science
Ukraine

Oleksandr Kislyi 2

Volodymyr Vynnychenko Central Ukrainian State Pedagogical
University
Bachelor’s Degree in Computer Science
Ukraine

Professional Development
Advancing expertise in scalable frontend and mobile application
architecture.
Expanding full-stack development skills with Node.js, PostgreSQL,
Supabase, and Prisma.
Developing technical leadership skills, including architectural decision-
making, task estimation, development planning, code reviews, and
mentoring.
Strengthening automated testing, CI/CD, application performance, and
release-management practices.
Exploring AI-assisted software development workflows using Claude Code,
Codex, MCP integrations, and specialized coding agents.

Skills
Core
React, Next.js, React Native, Expo, TypeScript, JavaScript

State Management and Data Fetching
Redux Toolkit, RTK Query, TanStack Query, Zustand, Axios

TanStack Ecosystem
TanStack Query, TanStack Table, TanStack Virtual

Forms and Validation
React Hook Form, Zod, Yup

UI and Styling
HTML, CSS, Tailwind CSS, shadcn/ui, Radix UI, Chakra UI, Ant Design

Oleksandr Kislyi 3

APIs and Real-Time
REST APIs, GraphQL, WebSocket, Socket.IO

Backend and Services
Node.js, Supabase, Firebase, Prisma, PostgreSQL

Testing
Playwright, Vitest

Tools and Workflow
Git, GitHub, GitHub Actions, Vite, Webpack, ESLint, Prettier, Claude Code,
Codex, MCP

Additional Information
English: B2 (Upper-Intermediate)
Ukrainian: Native
Based in Ukraine and available for remote work.
Open to full-time and contract opportunities.

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