Олександр

Oleksandr Kononuchenko
Frontend Developer
Location: Kyiv, Irpin
Languages: English (Intermediate), Ukrainian (Native), Russian (Fluent)
Phone: [відкрити контакти](див. вище в блоці «контактна інформація»)
Email: [відкрити контакти](див. вище в блоці «контактна інформація»)
Telegram: @peggy_13

General profile info
Frontend developer with 3+ years of commercial experience building production products with React and
TypeScript. Built an edtech web platform from scratch, delivering the frontend MVP in ~2 months, including a
custom UI kit, a custom rich text editor and a drag-and-drop test builder. Built an internal admin panel and a
web acquisition funnel that brings ~30-40% of a consumer app's users, and worked on a B2B enterprise
communication platform with real-time features. Introduced Feature-Sliced Design on a live product.
Experienced with Git Flow, pull request review and end-to-end feature ownership, including backend parts
(Node.js, NestJS, PostgreSQL).

Skills
Programming languages: JavaScript, TypeScript
Frontend: React, Tailwind CSS, TanStack Query (React Query), React Hook Form, Zustand, React Context,
Axios, Socket.IO, i18next, Vite, Next.js, Redux, styled-components, HTML, CSS/SCSS, React Native, Expo
Backend: Node.js, Express, NestJS, PostgreSQL, Redis, RabbitMQ, MikroORM, Prisma, Zod
Other: REST API, GraphQL (Apollo), WebSocket, WebRTC, Feature-Sliced Design, Domain-Driven Design,
monorepo (Turborepo, Nx), Git Flow, pull request review, GitHub Actions (CI/CD), ESLint, Prettier, Stylelint,
Jest, React Testing Library, Maestro, Firebase, Amplitude, Microsoft Clarity, AI-assisted development

Employment history
React / React Native Developer, WebbyLab, Kyiv, Ukraine
September 2024 - June 2026 · Project: Dealpump

Worked in a 5-person team (2 frontend, 1 backend, 1 QA, 1 PM) on a live production product (web + mobile)
under a full feature-ownership model: responsible for features end-to-end, from requirements and estimation to
implementation, code review, weekly releases and analytics-driven iteration.

- Built an internal admin panel from scratch (React, TypeScript, Vite) used daily by the
client's product team (5-7 people) for content creation and moderation, user
verification and premium content management: data tables with search and filtering,
create/edit forms, media upload and admin authentication
- Built the web acquisition funnel for the mobile app (FunnelFox) with web-based
authorization and deep-link auto-login; the funnel became the source of ~30-40% of
all users
- Built a browser video player so users without the app can watch shared videos on the
web

- Proposed and introduced Feature-Sliced Design, since the existing structure could
not support planned scaling: sped up feature development, made the codebase
testable with unit and E2E tests and set clear conventions for where code belongs
- Owned the user-generated content module end-to-end (frontend + Node.js/Express
API on PostgreSQL, built with Domain-Driven Design): posts, comments, public
profiles and a media upload pipeline with compression
- Implemented an AI virtual try-on feature based on the Google Gemini API
- Reviewed 3-5 pull requests per week, introduced test coverage (Jest, Testing Library,
Maestro) and maintained CI/CD pipelines on GitHub Actions

Frontend Developer (React / React Native), Tenthousand, Kyiv, Ukraine
February 2023 - August 2024 · Projects: Teach Space, Zultys MX Mobile, SpeakingAI

Teach Space - edtech platform for creating and taking educational tests, built from scratch (team of 6)

- Designed and built the frontend from scratch with React, Next.js and TypeScript,
delivering the MVP in ~2 months
- Proposed and architected a standalone monorepo package for complex test
components (rich editor, SVG animations, interactive elements), decoupling
rendering from the main app
- Built a custom UI kit of 30+ components from scratch without third-party libraries and
implemented 24 types of test and interactive elements
- Developed a custom lightweight rich text editor for authoring test content instead of a
heavy third-party library, since only a small subset of features was needed, keeping
bundle size and performance under control
- Implemented custom drag-and-drop for reordering test sequences and export of tests
to PDF

Zultys MX Mobile - B2B enterprise communication platform (web + mobile, 20k+ downloads)

- Supported and extended the web and mobile clients: real-time messaging and voice
calls over WebSocket and WebRTC
- Implemented group conference calls with up to 256 participants depending on the
system tier, extending calling that previously supported only one-to-one calls
- Fixed issues in connection handling: WebSocket/WebRTC reconnection and data
sync after network loss
- Developed a standalone contacts microservice (NestJS, Nx monorepo, PostgreSQL,
REST) integrated into the existing microservice architecture via RabbitMQ

SpeakingAI - AI-powered language speaking practice app (mobile)

- Built the mobile app from scratch (React Native, TypeScript) and delivered the MVP
in ~2.5 months, with real-time voice chat over WebRTC and OpenAI API integration
- Built a custom native audio module (iOS and Android) with real-time amplitude
events for voice messages
- Built a responsive landing page for the product from designs

Frontend Developer, Freelance, Remote
February 2022 - February 2023

Developed websites for direct clients, working on both new projects and existing codebases.

- Built landing pages, multi-page websites and an interactive online crossword app
with React, Next.js and Gulp
- Extended existing client projects and worked directly with clients on requirements,
estimates and progress