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I'm Andrii Kostromin, a Senior Full Stack Engineer with 15+ years of experience building scalable web applications across healthcare, fintech/financial media, e-commerce, and enterprise sectors. I specialize in React, Node.js, PHP, and Python, designing robust REST and GraphQL APIs, and I routinely leverage AWS, Docker, PostgreSQL, and MySQL. I value clean architecture, scalable design, and clear collaboration with clients and teams. I work directly with clients across time zones, gathering requirements, guiding architecture, and delivering demos at key milestones. I lead distributed teams of 5–15 engineers from discovery through production, owning code quality, architecture decisions, and delivery timelines, while emphasizing clear communication and thorough documentation.…I'm Andrii Kostromin, a Senior Full Stack Engineer with 15+ years of experience building scalable web applications across healthcare, fintech/financial media, e-commerce, and enterprise sectors. I specialize in React, Node.js, PHP, and Python, designing robust REST and GraphQL APIs, and I routinely leverage AWS, Docker, PostgreSQL, and MySQL. I value clean architecture, scalable design, and clear collaboration with clients and teams. I work directly with clients across time zones, gathering requirements, guiding architecture, and delivering demos at key milestones. I lead distributed teams of 5–15 engineers from discovery through production, owning code quality, architecture decisions, and delivery timelines, while emphasizing clear communication and thorough documentation.

Andrii Kostromin

Full Stack Developer, Web Developer, Back-End Developer, +3

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I'm Andrii Kostromin, a Senior Full Stack Engineer with 15+ years of experience building scalable web applications across healthcare, fintech/financial media, e-commerce, and enterprise sectors. I specialize in React, Node.js, PHP, and Python, designing robust REST and GraphQL APIs, and I routinely leverage AWS, Docker, PostgreSQL, and MySQL. I value clean architecture, scalable design, and clear collaboration with clients and teams. I work directly with clients across time zones, gathering requirements, guiding architecture, and delivering demos at key milestones. I lead distributed teams of 5–15 engineers from discovery through production, owning code quality, architecture decisions, and delivery timelines, while emphasizing clear communication and thorough documentation.…I'm Andrii Kostromin, a Senior Full Stack Engineer with 15+ years of experience building scalable web applications across healthcare, fintech/financial media, e-commerce, and enterprise sectors. I specialize in React, Node.js, PHP, and Python, designing robust REST and GraphQL APIs, and I routinely leverage AWS, Docker, PostgreSQL, and MySQL. I value clean architecture, scalable design, and clear collaboration with clients and teams. I work directly with clients across time zones, gathering requirements, guiding architecture, and delivering demos at key milestones. I lead distributed teams of 5–15 engineers from discovery through production, owning code quality, architecture decisions, and delivery timelines, while emphasizing clear communication and thorough documentation.

Available to hire

I’m Andrii Kostromin, a Senior Full Stack Engineer with 15+ years of experience building scalable web applications across healthcare, fintech/financial media, e-commerce, and enterprise sectors. I specialize in React, Node.js, PHP, and Python, designing robust REST and GraphQL APIs, and I routinely leverage AWS, Docker, PostgreSQL, and MySQL. I value clean architecture, scalable design, and clear collaboration with clients and teams.

I work directly with clients across time zones, gathering requirements, guiding architecture, and delivering demos at key milestones. I lead distributed teams of 5–15 engineers from discovery through production, owning code quality, architecture decisions, and delivery timelines, while emphasizing clear communication and thorough documentation.

Skills

Experience Level

Expert

Expert

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Language

English

Advanced

Ukrainian

Fluent

Russian

Fluent

Work Experience

Engineer at EPAM Systems

July 1, 2023 - March 1, 2024

Implemented GDPR-compliant webform submission with 3rd-party service integration; built a reusable plugin-based system for PDF generation and email dispatch across a multi-site factory; redesigned component architecture using Storybook and atomic design; improved SEO and accessibility scores via automated metatag generation and accessibility audit remediation.

Key Engineer at EPAM Systems

September 1, 2020 - February 1, 2021

Integrated CommerceTools for authentication, product catalog, and user data synchronization; resolved payment integration issues for PayPal and Ingenico; implemented Solr-based search with autocomplete and custom field mapping; performed code review, optimisation, and managed deployments across distributed team.

Full Stack Developer at Smile (formerly Adyax)

July 1, 2017 - June 1, 2019

Contributed to a large-scale financial media platform (80k+ articles per site) with paywall, subscriptions, and payment integrations; built internal GDPR document generator tool; delivered feature development, code reviews, and deployments across a 230+ site factory.

Team Lead at EPAM Systems

July 1, 2025 - March 1, 2026

Led frontend development using React component libraries; established and enforced development standards, ensuring code quality across the team; interviewed and onboarded new engineers; conducted regular code reviews and knowledge-sharing sessions.

Engineer at EPAM Systems

January 1, 2023 - June 1, 2023

REST API integration between Vue.js frontend, API gateway, and backend services; implemented OAuth2 authentication integration; upgraded legacy backend with full security audit and vulnerability remediation; managed deployments and CI/CD pipeline via Jenkins and GitHub.

Team Lead at EPAM Systems

July 1, 2022 - August 1, 2022

Led client-facing discovery: gathered requirements, produced MVP proposal, RFP, and effort estimations.

Architect at EPAM Systems

November 1, 2022 - December 1, 2022

Architecture review and integration design; produced architecture documentation: logical views, data models, infrastructure diagrams, risk register; proposed integration architecture for e-commerce and CRM systems.

Key Engineer at EPAM Systems

February 1, 2021 - June 1, 2022

Built search widgets and an admin dashboard for managing active search plugins and configuration history; developed API integration layer between Vue.js frontend and third-party search catalog services; improved code quality and eliminated deprecated code across a large multi-team codebase.

Full Stack Developer at Adyax / Smile / Zfort

July 1, 2015 - September 1, 2020

Built REST APIs, implemented payment flows, led CI/CD pipeline setup, and mentored junior developers across client projects in e-commerce, loyalty platforms, and publishing.

PHP Developer, Team Lead at Artmyweb / Hondo Software / SkidMe / Adyax

November 1, 2009 - July 1, 2015

Early-career role across approximately 15 client projects in e-commerce, social networking, media, and SaaS; led development efforts and client communications.