Андрій

Andrii Kobylin
Senior Full-Stack Engineer (React, Node.js) | Microservices | Testing & Performance
[open contact info](look above in the "contact info" section) • [open contact info](look above in the "contact info" section) • [open contact info](look above in the "contact info" section) • Ukraine

SUMMARY
Senior Full-Stack Engineer focused on building high-quality web products end-to-end: UI architecture,
backend integration, testing, and delivery. Experienced in taking ownership — from raw requirements and
wireframes to production-ready features — with a focus on business value, performance, and developer
experience. Core strengths include React-based frontends, component libraries/design systems, complex
forms & dashboards, microservice communication (gRPC/Protobuf), and reliable test automation (unit + E2E).

EXPERIENCE
Senior Full-Stack Developer | Miggo
May 2025 – Present · Kyiv, Ukraine
Tech: TypeScript, React, React Query, Zod, Jest, Node.js, Express, Drizzle ORM, TypeORM, PostgreSQL, Ant Design,
Styled Components, pnpm workspaces, Python, Temporal, SQLAlchemy, Alembic
Working on security/product platform features across frontend, backend, and data-processing workflows, with
a strong focus on performance, scalability, and developer experience.
• Wrote technical designs for complex features, including pagination and streaming for large datasets (up
to ~2M records)
• Optimized PostgreSQL queries and backend operations, improving performance by up to 5x
• Built configurable table filtering for large datasets and complex UI workflows
• Refactored legacy endpoints and added robust pagination support
• Developed reusable, strongly typed components in the internal UI library to improve consistency and
speed up feature delivery
• Worked across the Node.js backend stack (Express, ORM layer, PostgreSQL) to improve maintainability
and scalability
• Contributed as a Python developer on Temporal jobs/workflows for generating analytical data
• Implemented and tested complex Python workflows using SQLAlchemy, Alembic, and unit tests

Senior Web Developer | Robo Wunderkind
September 2023 – January 2025 · Vienna, Austria
Web-based IDE for educational robotics
• Designed and implemented an interactive tutorial flow guiding students through programming tasks,
improving onboarding experience
• Developed a browser-based firmware update tool for uploading firmware to robotic kits via USB directly
from the browser
• Helped build a microservice for storing per-robot domain names and synchronizing with DNS (DnsMasq)
and Strapi database
• Extended the IDE framework with new widgets for configuring physical robot modules; introduced
architecture improvements
• Integrated the IDE with Clever (education SSO) to streamline authentication and onboarding
• Set up Jenkins pipelines for automated deployment of Node.js services; supported release management
and code reviews
• Improved page speed and optimized GraphQL queries — reduced payload size for heavy endpoints by
90%

Senior Web Developer | Beetroot
March 2018 – October 2023 (5 years 8 months) · Kyiv, Ukraine
Tech: React, TypeScript/JavaScript, React Query, Redux, Material UI, SASS, WebSockets, Cypress, Jest, D3, Leaflet,
Python, FastAPI, PostgreSQL, Docker, GitLab CI, gRPC, gRPC-Web, Protobuf, Webpack
Project: Hospihousing — Booking Platform (Apr 2022 – Apr 2023)
• Built an interactive map experience using Leaflet (clustering + navigation) for improved discovery and
UX
• Implemented real-time chat using WebSockets
• Developed an apartment listings grid with filtering and availability logic
• Created a multi-step registration flow with validation and smooth onboarding UX
Project: Empowered — CRM for Medical Centers (Apr 2020 – Apr 2022)
• Refactored legacy frontend code to improve maintainability and overall product stability
• Built an internal component library with Storybook
• Created interactive data visualizations with D3.js for medical analytics
• Profiled and optimized Webpack (CPU/RAM), improving build performance and developer productivity
• Dockerized the app and configured GitLab CI for automated tests and linting (ESLint)
Project: MTRX Trains — Rail Ticket Booking Platform (Apr 2018 – Apr 2020)
• Designed scalable frontend architecture and selected frameworks/libraries to improve maintainability
• Led transition from legacy AngularJS to modern React frontend (incremental migration)
• Helped design browser ↔ microservices communication using Protobuf + gRPC/gRPC-Web

Senior Software Developer | Freelance
September 2017 – February 2018 · Ukraine
Project: Kyiv Library Network (soloma.libraries.kyiv.ua)
• Built a public website (WordPress) and Telegram bot to improve discovery and reservation of books
across district libraries
• Customized WordPress with custom content types, integrated with electronic catalog system, deployed
behind Cloudflare
• Built @SolomaLibBot on Telegram enabling users to search and reserve books via the messaging app

Senior Web Developer | Luxoft
July 2016 – July 2017 · Kyiv, Ukraine
Getty Images — Media Manager Migration
Tech: AngularJS 1.5, Node.js, Express, Microservices, XML/XSLT, LESS, BEM, Gulp, GitLab CI, Jenkins
• Migrated a legacy Java + XSLT media manager application to a modern SPA and microservices
architecture (team ~40)
• Built reusable UI components (tree view, dropdowns, panels) and key pages (admin, media, upload,
cart)
• Extended Node.js proxy service with aggregation endpoints and access control for different resource
types
• Added unit/functional test coverage; participated in cross-team code reviews via GitLab CI and Jenkins

Software Engineer | DataRobot
October 2015 – April 2016
Tech: AngularJS, ES6, LESS, RequireJS, Grunt, D3.js, Protractor, Karma, REST, Python
• Built complex UI components in AngularJS including data-driven visualizations with D3.js
• Collaborated with backend engineers to define REST API contracts and edge cases
• Added unit tests (Karma) and E2E tests (Protractor); profiled and optimized SPA performance
• Fixed selected bugs in Python backend to unblock features; contributed to i18n/l10n support

Web Developer | Web Tech Media Group STHLM AB
September 2014 – April 2015 · Stockholm, Sweden
Projects: PlayAd, Gapminder
 • Built a single-page presentation site for PlayAd using jQuery and Sass
• Integrated multiple parts of Gapminder's statistics system: data processing, storage, and display
• Developed an interactive population-by-age chart component using D3.js

JavaScript Developer | Innovecs
April 2013 – July 2014 · Kyiv, Ukraine
Supply Chain Management Platform
Tech: AngularJS, Ext JS, Backbone, Node.js, Express, MongoDB, Socket.IO, D3.js, jQuery, Sass
• Built core product UI using Ext JS and interactive prototypes with jQuery + Backbone
• Developed an event triage sub-app (Node.js + MongoDB) filtering Twitter feeds by disaster/event
keywords for operator review
• Built the elementum.com promo site with parallax effects and responsive behavior
• Created supply chain activity visualizations using AngularJS + D3.js with Express backend

JavaScript Developer | Freelance
January 2012 – March 2013
Wikipedia Statistics Analytics Tool
Tech: Node.js, Express, EJS, Memcached, Knockout.js
• Built full-stack analytics tool analyzing activity within specified Wikipedia categories
• Implemented Memcached caching for repeated API requests; built frontend using Knockout.js and EJS

EDUCATION
Master's Degree, Computer Science
National Technical University of Ukraine 'Kyiv Polytechnic Institute' · 2005 – 2011

KEY SKILLS
Frontend: React, TypeScript, JavaScript (ES6+), Redux, React Query, Material UI, D3.js, Leaflet, Webpack,
SASS/LESS
Backend: Node.js, Express, Python, FastAPI, gRPC/Protobuf, GraphQL, REST, WebSockets
Databases: PostgreSQL, MongoDB
Testing: Cypress, Jest, Karma, Protractor, Selenium
DevOps & Tools: Docker, GitLab CI, Jenkins, Storybook, Cloudflare
Languages: English (professional), Ukrainian (native)