Oleksandr

Oleksandr Serhiienko
Frontend Developer with Fullstack Focus
[открыть контакты](см. выше в блоке «контактная информация») [открыть контакты](см. выше в блоке «контактная информация») Othmarsingen, Switzerland

PROFILE
Frontend Developer with 4+ years of commercial experience building production-grade web applications
using React, Next.js, and TypeScript. Strong background in API-driven systems, complex dashboards, and
data-intensive applications across healthcare, SaaS, genomics, and Web3 domains.
Hands-on experience integrating frontend applications with HL7 FHIR-based healthcare systems, including
working with FHIR resources, search queries, data aggregation, and generation of FHIR-compliant payloads.
Experienced in international, distributed teams and in leading frontend development on long- term
enterprise projects. Currently expanding backend expertise with NestJS and Express to grow into a fullstack-
oriented role while maintaining strong frontend ownership and architectural responsibility.

PROFESSIONAL EXPERIENCE
Frontend Developer 08/2021 – 09/2025
Incode Group Dnipro, Ukraine
Worked as a Frontend Developer in an outsourcing environment, delivering
production-ready web applications for international clients using React, Next.js, and
TypeScript. Key responsibilities and achievements:
Led frontend development of a healthcare application for a hospital in the
•

Netherlands, taking ownership of UI architecture and core frontend logic
Integrated frontend applications with HL7 FHIR-based APIs, including resource
•

handling, complex search queries, data aggregation, and form-driven generation
of FHIR-compliant payloads
Refactored legacy frontend code, improving application performance by
•

approximately 15%
Reduced overall codebase size by around 20% through modularization and removal
•

of redundant logic
Designed and maintained stable data flows between frontend and backend
•

through complex REST APIs
Coordinated a team of 4 frontend developers: task breakdown, technical guidance,
•

and delivery control
Collaborated daily with distributed teams across the Netherlands, India, and
•

Ukraine
Worked with Azure for deployment, environment configuration, and cloud-related
•

tasks
Maintained high code quality through code reviews, shared standards, and
•

structured development processes
CORE SKILLS
Frontend
JavaScript (ES6+), TypeScript
•

React, Next.js
•

HTML, CSS, responsive design
•

Performance optimization, refactoring, maintainable architecture
•

Backend (Growing)
NestJS, Express
•

REST APIs, backend fundamentals
•

API integration and data flow design
•

Healthcare & Domains
HL7 FHIR frontend integration
•

Working with FHIR resources, search queries, and data aggregation
•

Building and submitting FHIR-compliant payloads
•

Cloud & DevOps
Azure
•

Docker
•

CI/​CD pipelines
•

Tools
Git
•

Swagger /​API documentation
•

Figma, Adobe XD
•

LANGUAGES
Ukrainian Russian
Native Native

English German
B2 (Professional working proficiency) A1 (Currently learning)

EDUCATION
Bachelor of Science (BSc), Computer Science 09/2020 – 07/2024
Dnipro University of Technology Dnipro, Ukraine
Master of Science (MSc), Computer Science 09/2024 – 01/2026
Dnipro University of Technology Dnipro, Ukraine
Master of Science (MSc), Economics 09/2024 – 01/2026
Dnipro University of Technology Dnipro, Ukraine

SELECTED PROJECTS
Healthcare Application
Stack: React, TypeScript, HL7 FHIR, CSS
Implemented a new frontend design system based on Figma designs
•

Integrated the application with FHIR-based healthcare APIs
•

Built performant search, filtering, and aggregation for healthcare datasets
•

Developed complex forms generating FHIR-compliant payloads
•

Genomics Data Visualization Platform
Stack: React, TypeScript, REST APIs
Built frontend interfaces for genomics data processing and visualization
•

Integrated data-intensive APIs and dynamic UI components
•

Delivered production features under tight timelines in a contract-based environment
•

Saas Dashboard (API-First Architecture)
Stack: React, TypeScript, REST APIs, Swagger
Developed complex dashboards for subscriptions, carts, and user profiles
•

Integrated multiple backend services documented via Swagger
•

Worked with evolving backend specifications and incomplete documentation
•
 Implemented clean, maintainable frontend logic for core business workflows
•

Web3 Frontend Console Applications
Stack: React, TypeScript, Web3, REST APIs
Designed and implemented frontend architecture for mission-critical applications
•

Integrated EVM wallets, smart contracts, and backend services
•

Focused on performance, scalability, and long-term maintainability
•

Participated in architectural discussions and code reviews
•

Product-Oriented Web Applications
Stack: React, TypeScript, Responsive Design
Built responsive user interfaces based on Figma designs
•

Focused on UX consistency and reusable component architecture
•

Optimized pages for performance and scalability
•