Open to opportunities

Сергей Коломойченко

@0005775

Message

I build reliable React products from architecture through production release.

Russian Federation

Message

What I'm looking for

I'm looking to own challenging frontend or mobile product delivery end to end, from stakeholder discovery and architecture through testing and release, while improving reliability, shared platform code, and delivery processes.

At X5 Tech, I own end-to-end frontend delivery for retail digital products, including catalog, content, promotions, stores, and checkout across admin tools, customer websites, and in-app WebView.

I work in an Nx monorepo of roughly 19 apps and shared libraries, building production-ready React features with Vitest, React Testing Library, Playwright, and CI. I focus on stabilizing critical paths, improving coverage around risk, and refactoring shared code so teams avoid repeating the same bugs.

Previously at Открытие Инвестиции, I built a premium-client banking workspace for accounts, products, transfers, and loan origination. I integrated real-time WebSocket updates and validated flows with Kafka while working through the rigorous review and QA cycles banking requires.

I've also delivered a React Native irrigation app connected to field hardware in real time, and built full-stack university systems with Python, Django, PHP, and SQL. I enjoy hard, messy problems and take them through to release.

Experience

Work history, roles, and key accomplishments

Current

Senior Frontend Developer

Current

X5 Tech

May 2024 - Present (2 years 4 months)

Own end-to-end frontend delivery for retail digital surfaces, including internal admin tools, customer-facing websites, and in-app WebView. Lead features from stakeholder discovery and architecture through implementation and release, balancing tight MVP scope with structured planning.

React Vitest React Testing Library Playwright Scrum Kanban CI CD DevOps Security

Current

Старший разработчик

Current

X5 Tech

May 2024 - Present (2 years 4 months)

Own end-to-end frontend delivery for retail digital surfaces: internal admin tools, customer-facing websites, and in-app WebView — catalog, content, promotions, raffles, stores, and checkout.

Lead features from stakeholder discovery and architecture through implementation and release, balancing tight MVP scope with structured planning when the product needs it.
Keep stability as a default: decom

Frontend Developer

Открытие Инвестиции

Sep 2022 - May 2024 (1 year 8 months)

Built and evolved a premium-client banking workspace: accounts, products, transfers, and day-to-day work with client money — a full bank application for relationship managers, not a simple CRUD admin.
Shipped new banking products and wired them into existing flows (for example, online loan origination with document checks).
Integrated live UI over WebSockets so operators saw status updates during

Senior Frontend Developer

WellYes

Feb 2019 - Jun 2023 (4 years 4 months)

Built a React Native app (iOS and Android) for an Israeli irrigation product: watering schedules, valve control, fertigation and irrigation setup, and subscriptions — talking to real field hardware over WebSockets.
Owned the mobile client end to end: schedule UI, device control, subscription flows, and live communication with microcontrollers.
Integrated WebSockets so operators could open valves a

Программист

Ухтинский Государственный Технический Университет

Aug 2014 - Sep 2019 (5 years 1 month)

Built and maintained university websites and internal systems of different complexity — from greenfield projects to support and evolution of existing ones. Full-stack delivery, plus user support and basic campus network setup.
Designed and shipped new web sites and internal tools from scratch (requirements → implementation → release).
Supported and extended live systems used by staff and students;