Олег

OLEH SERBIN
Backend Engineer
[відкрити контакти](див. вище в блоці «контактна інформація») • [відкрити контакти](див. вище в блоці «контактна інформація») • gitlab.com/oserbin • [відкрити контакти](див. вище в блоці «контактна інформація»)

PROFESSIONAL SUMMARY
Backend Engineer with 10+ years of overall experience, specializing in Node.js, TypeScript, and Go for the past 5+ years.
Proven track record of delivering resilient REST APIs, asynchronous backend microservices, and optimized data layers
across PostgreSQL, MySQL, SQLite, and MongoDB. Combines an enterprise engineering foundation with a strong
commitment to clean architecture, software craftsmanship, and local-first software design.

CORE COMPETENCIES
Programming Languages: TypeScript, JavaScript, Go
Backend & Systems: Node.js, REST APIs, GraphQL, Microservices, Monolithic, System Architecture
Databases & Caching: PostgreSQL, MySQL, SQLite, Neo4j, Redis, MongoDB, Query Optimization
DevOps & Tools: Docker, Caddy, Linux (Ubuntu), Git, GitLab CI/CD

PROFESSIONAL EXPERIENCE
Quint Project (Open Source) Kyiv, Ukraine
Full-Stack Engineer Feb 2026 – Present
Architected and implemented a local-first, self-hosted knowledge management system designed for individual users
and small teams.
Engineered a high-performance backend architecture using Go and SQLite, focusing on low resource footprint, efficient
data persistence.
Developed responsive client-side interfaces and offline-capable workflows using JavaScript, HTML and Tailwind CSS.
Connact GmbH Kyiv, Ukraine (Remote)
Backend Developer (Contractor) Jul 2025 – Oct 2025
Developed, customized, and optimized server-side features for web applications using Node.js, Express.js, and
JavaScript.
Designed and maintained NoSQL database models and queries in MongoDB to ensure efficient data handling and quick
retrieval.
Bomi Kyiv, Ukraine (Remote)
Backend Developer Jan 2024 – May 2025
Architected and implemented a scalable server-side solution from scratch using Node.js, NestJS, and TypeScript.
Designed relation-rich database schemas in MySQL with TypeORM, optimizing queries and indexing for robust data
integrity.
Developed GraphQL APIs for efficient client data fetching and integrated Redis for caching and session management.
PlayHQ Kyiv, Ukraine (Remote)
Backend Engineer (Contractor) Dec 2020 – Nov 2023
Engineered and maintained microservices within a distributed architecture using Express.js, TypeScript, and GraphQL.
Managed complex graph-based data structures in Neo4j while working with microservices integrated with PostgreSQL
and MongoDB.
Contributed to Go-based backend services and CLI tools in Go.
Implemented new feature requirements, refactored existing codebases, and resolved bugs to maintain system stability.
Covered core business logic and API endpoints with integration and e2e and unit tests using Jest.
Freelance Kyiv, Ukraine
Full Stack JS Developer Aug 2019 - Nov 2020
Designed and delivered an end-to-end knowledge-sharing and team collaboration system.
Built scalable Node.js/Express.js backend services paired with MongoDB for flexible document storage.
Enabled real-time cross-team communication via Socket.io and developed cross-platform interfaces (React, Electron,
React Native).
Covered core business logic and API endpoints with integration and unit tests using Jest.

BlaBlaCar Kyiv, Ukraine (Remote)
Software Engineer Jan 2014 - Jul 2019
Designed, customized, and expanded web application features using PHP (Symfony), MySQL, and Elasticsearch.
Covered core business logic with unit and integration tests to ensure stability and prevent regressions.
Resolved complex bugs, optimized database interactions, and improved overall codebase quality.
Podorozhniki Kyiv, Ukraine
CTO Jan 2012 - Dec 2013
Led technical decision-making and architected backend services to ensure scalable and reliable application
performance.
Engineered robust RESTful APIs using PHP and MySQL, optimizing database schema design and query execution.
Developed client-side business logic and interactive UI components using JavaScript.
Ngoar Kyiv, Ukraine (Remote)
Senior .NET Developer Jul 2011 - Dec 2011
Built e-commerce platforms and cross-system integrations connecting .NET (Umbraco/uCommerce) with PHP
(Magento) via custom APIs and SOAP interfaces.
Maintained multi-stack web applications (C#, PHP, MySQL), improving legacy codebase reliability and data workflows.
Smile Ukraine Kyiv, Ukraine
Senior .NET Developer May 2008 - Jul 2011
Developed and supported ERP system (C#, ASP.NET, MS SQL Server), implementing core business workflows and
data-intensive services.
Improved system reliability and code quality through unit testing (NUnit) and automated testing pipelines with
Selenium.
Intellect Technologies Kyiv, Ukraine
Senior .NET Developer (part-time) Feb 2008 - May 2008
Developed full-stack web application using C# (.NET Framework), ASP.NET, and MS SQL Server, delivering dynamic
user interfaces.
Luxoft UA Kyiv, Ukraine
.NET Developer Oct 2005 - Dec 2007
Developed enterprise-level web applications and custom SharePoint services using C# (.NET Framework), ASP.NET,
and MS SQL Server.
Designed analytical reporting modules (OLAP cubes) and dynamic client-side interfaces using JavaScript and early
AJAX patterns
Royal Holding Kyiv, Ukaine
Software Developer (part-time) Jul 2003 - Oct 2005
Engineered web applications and automated data reporting services using C# (.NET Framework), ADO.NET, and MS
SQL Server (T-SQL), including custom Excel/XML data processing pipelines.
Executed end-to-end quality assurance strategies, creating comprehensive test plans and writing automated test scripts
to ensure high web application reliability.

EDUCATION
National Taras Shevchenko University of Kyiv Kyiv, Ukraine
Faculty of Mechanics and Mathematics
Specialist of Mechanics. Sep 2000 – Jun 2005

LANGUAGES:
English: Professional Working Proficiency
Ukrainian: Native