Сергій

Serhii Parfeniuk
Senior Backend Engineer | PHP / Laravel / Node.js | Healthcare, Logistics, Web3
[відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація») | Lviv, Ukraine | Open to remote
LinkedIn: [відкрити контакти](див. вище в блоці «контактна інформація») | Telegram: @sp_work

SUMMARY
Backend engineer with 6+ years of experience building production PHP/Laravel and Node.js systems across healthcare,
logistics, and Web3. Strong in refactoring legacy monoliths, designing REST APIs, improving test coverage, and integrating AI
into existing workflows. Comfortable owning backend services end-to-end, from architecture and database design to
Docker-based deployment and production support. Practices regular mentoring and code review across the team.

TECHNICAL SKILLS
Backend PHP 8.4, Laravel 13, Symfony, Yii2, Node.js, Express
Databases MariaDB, MySQL, PostgreSQL, Redis, Elasticsearch, SQL
Cloud / DevOps AWS (S3, SQS, Textract), Docker, CI/CD, Linux server configuration
Integrations RESTful APIs, SOAP, HL7, Web3 / Ethereum, AI / Computer Vision
Frontend Vue, Blade, TypeScript, JavaScript
Practices TDD, unit & functional testing, microservices, code review, mentoring, Agile/Scrum

PROFESSIONAL EXPERIENCE
Backend Engineer May 2023 – Present
CodeIT · Remote
• Development for a US-based drug-testing platform on PHP 8.4 / Laravel 13 serving 2,400+ active organizations and
processing ~400k tests per year; results trusted by US federal institutions, courts, and insurance companies.
• Integrated with major US testing labs — Quest Diagnostics, AverHealth, Cynergy MRO, and Desert Tox — via REST and
SOAP for order submission and result parsing.
• Built the HL7 file generator from scratch, producing standards-compliant order and result messages consumed by all
integrated labs.
• Built the backend powering a real-time AI test-cup review pipeline, analyzing hundreds of thousands of urine and oral-fluid
images to date and replacing manual reviewer steps.
• Drive code reviews and architecture decisions across a 7-engineer backend team.
• Added functional test coverage to previously untested billing and reporting flows, eliminating a recurring source of
production regressions.
Full-Stack Developer (Laravel / Vue) Jun 2022 – May 2023
InoXoft · Lviv
• Delivered backend and full-stack features for SiteCircle (app.sitecircle.co.uk), a UK time-log service for construction crews
— built microservice integrations and Redis-cached reporting endpoints.
• Contributed to the SandMilk NFT marketplace (Node.js, PostgreSQL, Web3/Ethereum) — implemented on-chain
transaction handling and minting workflows.
• Refactored core project structure, added unit-test coverage to high-risk modules, and authored internal documentation
that became the team’s onboarding reference.
• Mentored 2 junior developers and ran code reviews on a team of 4.
Laravel Backend Developer Sep 2021 – May 2022
Product Company (NDA) · Lviv
• Built microservices on PHP 8 / Laravel with Elasticsearch search, AWS (SQS, S3, Textract) document pipelines, and
Redis caching; covered critical paths with unit tests.
Laravel Backend Developer Dec 2020 – Sep 2021
Devseonet · Lutsk
• Supported and extended production projects (ornet.com.ua, jobian.com, admin panel for uskologistics.com) —
refactoring, bug-fixing, and feature work in direct contact with customers.
Backend Developer (Symfony / Laravel / Yii2) Feb 2019 – Dec 2020
Dreamext · Lutsk
• Built backend APIs for the moniheal.com telemedicine platform (PHP / Symfony / Laravel / Yii2) on a team of 11 — set up
online payments and integrated third-party medical APIs.
• Participated in architecture decisions and code reviews; optimized CI build pipelines and added test coverage to legacy
services.
Education: Associate Degree, Software Development — IT-Step Academy, Lutsk (2016–2018)
Languages: English — B2 (Upper-Intermediate) · Ukrainian — Native