avatarAndrii Sulzhyk

Sulzh — Product Engineering | Frontend Engineering | Software Engineering | Full stack Engineering

I build production web applications and own product challenges end-to-end — from frontend architecture and UX decisions to API integrations and delivery.

View my work ↘Get in touch ↗
01 / About & selected work

From complex
to useful.

I'm a product-minded Software Engineer with 9 years of experience turning complex requirements into production software across fintech, healthcare, and e-commerce.

My deepest expertise is in frontend engineering with React and TypeScript, but my work has increasingly extended across product decisions, API design and integration, backend services, architecture, and end-to-end delivery.

Most recently, I spent 3.5 years at Rail, a fintech infrastructure startup acquired by Ripple, I joined as the first dedicated frontend engineer and built three production applications from the ground up. My work covered frontend architecture, complex operational workflows, authentication, API integrations, and end-to-end feature delivery.

I enjoy working across product, design, frontend, and backend boundaries to turn complex requirements into useful, reliable software.

I'm currently expanding my expertise in product and AI engineering, building on my frontend background to take broader ownership across the product lifecycle.

Selected work

Most recent first / 2014–2026
Rail fintech project cover with blue abstract waves and labels for management, onboarding, and internal admin interfaces

Rail · acquired by Ripple

Building fintech applications at Rail

Senior Frontend Engineer
December 2022 – July 2026

Rail built B2B payment infrastructure connecting traditional banking rails with stablecoins. By 2025, Rail powered over 10% of global B2B stablecoin payment volume. I joined as its first dedicated frontend engineer and went on to own frontend development across three production applications serving customers and internal teams.

  • Management UI — customer-facing financial operations.
  • Onboarding UI — self-service customer and compliance onboarding.
  • Internal Admin UI — operational tooling for Support, Compliance, and Operations.
  • React
  • TypeScript
  • Redux Toolkit
  • RTK Query
  • Node.js
  • Express
  • Jest
  • Webpack
  • TanStack Router
  • TanStack Table
  • Material UI
  • HTML
  • CSS
  • SCSS
  • Auth0
  • Okta
  • OAuth/OIDC
  • GitHub Actions
  • GitHub Copilot
  • Claude code
  • Figma
Explore case study
Knowledge management platform

DAXX / Grid Dynamics

Scientific data visualization

Frontend Developer
November 2018 – November 2022

Contributed to React application for NDA bioengineering research and knowledge-management platform.

  • Worked on React application for bioengineering research and knowledge-management platform serving scientific users.
  • Designed and implemented complex data visualization experiences using D3.js, including: force-directed graphs; heatmaps; hierarchical tree visualizations; line charts; pie charts; custom SVG-based scientific diagrams.
  • Built reusable visualization components capable of rendering large biological datasets while maintaining smooth interaction and performance.
  • Collaborated with managers and backend engineers to transform complex domain data into intuitive interactive user experiences.
  • Contributed to frontend architecture, Redux state management, Redux Saga middleware, reusable component libraries and dashboard development.
  • Mentored and conducted technical interviews for UI engineers.
  • React
  • D3.js
  • SVG
  • Redux
  • Redux Saga
  • Axious
  • Reselect
  • HTML
  • CSS
  • SCSS
  • Git
E-commerce experiences

Omnicore

E-commerce experiences

Junior Frontend Developer
June 2017 – October 2018

Built corporate websites and contributed to e-commerce shopping experiences.

  • Developed and maintained the company’s corporate website.
  • Developed e-commerce websites for big Ukrainian retailers: New Balance, Vsi Svoi, MD Fashion, UltraShop.
  • Worked on markup, Photoshop and Figma design-to-code implementation across multiple commercial websites.
  • Implemented responsive, pixel-accurate website layouts, frontend interactions, and scroll-based animations for commercial e-commerce and corporate websites.
  • JavaScript
  • jQuery
  • HTML
  • CSS
  • SCSS
  • Handlebars
  • Webpack
E-commerce experiences

Olshansky & Partners

Marketing & growth

Internet Marketing Specialist
August 2014 – August 2016

Before moving into software engineering, I worked in digital marketing and SEO, gaining hands-on experience with customer acquisition, analytics, conversion optimization, and online business growth. That background still shapes how I approach software today — not just as a technical system, but as a product built to solve user and business problems.

  • Developed marketing strategies.
  • Wrote technical SEO audits.
  • Setted up email marketing campains.
  • Implemented SEO recomendations on WordPress websites.
  • SEO
  • PPC
  • Email Marketing
  • Marketing Strategies
  • Digital Marketing
  • Wordpress

Additional freelance work

01

NDA Project

During one year contributed to a React Native / Expo expense-tracking mobile application, including navigation flows, screens, charts, and API integrations.

02

NDA Project

Developed production Next.js corporate website including: design, architecture, responsive UI, deployment, and SEO.

03

Beforis

Implemented technical SEO improvements in an existing production Vue.js application, including canonical URLs, redirects, metadata, and indexing. Improved the mobile Lighthouse performance score from 64 to 97 through targeted performance optimizations.

04

Cardiolise

Contributed to ECG & HRV analytics platform using React JS, Ant Design and CSS in JS.

05

Twin Win Games

Created and maintained a company corporate WordPress website. Built HTML5 player interactions in collaboration with artists, product managers, and backend developers.

02 / Skills

Connected skills.
Complete products.

A working set, connected by product thinking.

Frontend

Interfaces, architecture, and reusable components for production web and mobile products.

  • React
  • TypeScript
  • React Native
  • Next.js
  • Architecture
  • State Management
  • Performance
  • Testing
  • Design Systems

Backend & APIs

Backend-for-frontend integrations, API communication, and secure authentication flows.

  • Node.js
  • Express
  • REST
  • API contracts
  • Authentication
  • Integrations

Data visualization

Interactive scientific interfaces that make complex biological data easier to explore.

  • D3.js
  • SVG
  • Canvas
  • Graphs
  • Heatmaps
  • Hierarchical trees
  • Boxplots

Delivery & Architecture

Version control, testing, continuous delivery, and design collaboration.

  • Technical design
  • CI/CD
  • Observability
  • Testing strategy
  • Release ownership

Product & UX

Ownership across requirements, user experience, implementation, and production.

  • Product discovery
  • Requirements
  • Feature ownership
  • UX decisions
  • Iteration
  • Marketing & SEO

Currently expandingLearning & development

Actively developing deeper AI, backend and database expertise.

  • System Design
  • SQL
  • AI Engineering
  • Backend Architecture
  • Database Design
03 / Contact

Let’s build
something
useful.

A product challenge, a role, or an idea?
I’d like to hear about it.

[email protected] ↗

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