Oleksandr

Oleksandr Serhiienko
Frontend Developer with Fullstack Focus
[open contact info](look above in the "contact info" section) [open contact info](look above in the "contact info" section) 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
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Netherlands, taking ownership of UI architecture and core frontend logic
Integrated frontend applications with HL7 FHIR-based APIs, including resource
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handling, complex search queries, data aggregation, and form-driven generation
of FHIR-compliant payloads
Refactored legacy frontend code, improving application performance by
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approximately 15%
Reduced overall codebase size by around 20% through modularization and removal
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of redundant logic
Designed and maintained stable data flows between frontend and backend
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through complex REST APIs
Coordinated a team of 4 frontend developers: task breakdown, technical guidance,
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and delivery control
Collaborated daily with distributed teams across the Netherlands, India, and
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Ukraine
Worked with Azure for deployment, environment configuration, and cloud-related
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tasks
Maintained high code quality through code reviews, shared standards, and
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structured development processes
CORE SKILLS
Frontend
JavaScript (ES6+), TypeScript
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React, Next.js
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HTML, CSS, responsive design
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Performance optimization, refactoring, maintainable architecture
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Backend (Growing)
NestJS, Express
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REST APIs, backend fundamentals
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API integration and data flow design
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Healthcare & Domains
HL7 FHIR frontend integration
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Working with FHIR resources, search queries, and data aggregation
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Building and submitting FHIR-compliant payloads
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Cloud & DevOps
Azure
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Docker
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CI/​CD pipelines
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Tools
Git
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Swagger /​API documentation
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Figma, Adobe XD
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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
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Integrated the application with FHIR-based healthcare APIs
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Built performant search, filtering, and aggregation for healthcare datasets
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Developed complex forms generating FHIR-compliant payloads
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Genomics Data Visualization Platform
Stack: React, TypeScript, REST APIs
Built frontend interfaces for genomics data processing and visualization
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Integrated data-intensive APIs and dynamic UI components
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Delivered production features under tight timelines in a contract-based environment
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Saas Dashboard (API-First Architecture)
Stack: React, TypeScript, REST APIs, Swagger
Developed complex dashboards for subscriptions, carts, and user profiles
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Integrated multiple backend services documented via Swagger
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Worked with evolving backend specifications and incomplete documentation
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 Implemented clean, maintainable frontend logic for core business workflows
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Web3 Frontend Console Applications
Stack: React, TypeScript, Web3, REST APIs
Designed and implemented frontend architecture for mission-critical applications
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Integrated EVM wallets, smart contracts, and backend services
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Focused on performance, scalability, and long-term maintainability
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Participated in architectural discussions and code reviews
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Product-Oriented Web Applications
Stack: React, TypeScript, Responsive Design
Built responsive user interfaces based on Figma designs
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Focused on UX consistency and reusable component architecture
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Optimized pages for performance and scalability
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