Dan

Dan Sytnikov
Senior Frontend Developer · React / React Native / TypeScript / Node.js
[відкрити контакти](див. вище в блоці «контактна інформація») · [відкрити контакти](див. вище в блоці «контактна інформація») · Remote-first · Open to relocation
[відкрити контакти](див. вище в блоці «контактна інформація») · github.com/DanSytnikov

PROFILE
Senior Frontend Engineer with 6+ years of commercial experience, specialising in React and React Native (Expo) with
TypeScript. Strong background in modern frontend architecture, cross-platform development, and building scalable
design systems from the ground up.
Deep expertise in regulated environments — led frontend development of a HIPAA-compliant healthtech platform with
complex EHR integrations, Okta-based auth flows, and real-time data pipelines. Delivered greenfield products end-to-
end across healthcare, fintech, and edtech.
Product-minded engineer who translates business requirements into technical decisions, estimates effort accurately,
and prioritises pragmatically. AI-native — actively uses agentic coding workflows and multi-agent pipelines as part of
daily development practice.

TECHNICAL SKILLS
Core React, React Native (Expo), Next.js, TypeScript, JavaScript (ES2022+)
State / Data Redux Toolkit, RTK Query, TanStack Query, Zod, Zustand
Mobile Expo Router, Expo SDK, Apple HealthKit, Google Health Connect
Styling Tailwind CSS, SASS/SCSS, CSS Modules, Material UI, Ant Design, shadcn/ui, Radix UI
Animation Framer Motion, React Native Reanimated
Testing Jest, React Testing Library, Cypress
Auth Okta, OAuth 2.0, JWT
Analytics Segment, PostHog, Google Tag Manager, Pendo, Amplitude
Tooling Storybook, Turborepo, Vite, Webpack, ESLint, Husky, Figma, Zeplin, Sentry
AI OpenAI API, LLM integration, Claude Code (CLI, agents), GitHub Copilot, GPT-4, Gemini
Backend Node.js, Express.js, PHP, Livewire (TALL stack)
Other Git, GitHub Actions, WebSockets, Agile/Kanban, HIPAA compliance, TDD, SOLID

EXPERIENCE
Senior Frontend Developer · Lean Digital Agency Nov 2023 – Present
Olivia Health (oliviahealth.ai) — AI-powered personal health concierge platform by Tempus AI
• Greenfield project: bootstrapped the entire frontend architecture for web (Next.js) and mobile (Expo Router / React
Native) from scratch, including a Storybook-based design system and state management with Redux Toolkit +
TanStack Query
• Integrated Apple HealthKit and Google Health Connect for automatic import of 20+ health metrics; implemented
real-time data sync for live health feed updates
• Implemented Okta-based auth and session management across web and mobile, covering login, registration, and
secure token flows in full HIPAA compliance
• Built EHR integrations with Epic and 24,000+ healthcare institutions via WebSockets for real-time connection state
updates, enabling seamless patient data import and reducing manual data entry for users
• Shipped an AI health assistant with OpenAI API streaming responses — users can query their medical records and
receive personalised health insights in real time

• Maintained architectural consistency across multiple team changes; led onboarding of new engineers and served as
primary technical reference for the project
Teladoc Health (teladochealth.com) — #1 global telehealth platform, 100M+ users
• Shipped new product features and translated Figma designs into pixel-perfect, responsive UI components across
the web application
• Optimised rendering performance — identified unnecessary re-renders and applied memoisation strategies,
resulting in measurably smoother interactions

Senior Frontend Developer · Quanti Coders 2020 – 2024
Serious Magic (seriousmagic.co) — Gamified decision-making learning platform
• Designed and delivered 8–10 interactive educational games end-to-end for web and React Native, each covering a
distinct mental model with multi-level progression and rich animations via React Native Reanimated and Framer
Motion
• Architected a Turborepo monorepo with a shared component library published as internal npm packages, powering
a unified game launcher portal that loaded games from independent repositories — improving team velocity
significantly
WellnessDetector — Admin dashboard for a contactless vital sign screening device
• Designed and built the entire frontend from scratch with no provided designs — delivered a data-rich D3 / Recharts
dashboard visualising real-time health metrics (temperature, heart rate, lung function) measured non-invasively
from 1–3 metres
Voyij.com — Alaska e-commerce marketplace for local gifts, tours & activities
• Led full migration of a large marketplace to the TALL stack (Tailwind CSS, Alpine.js, Laravel, Livewire), preserving
complex multi-category catalogue, bookings, and cruise-line integrations across storefront and vendor flows
SparrowInvest (joinsparrow.co) — Bitcoin investment platform for women
• Developed the investment dashboard with portfolio tracking, community features, and real-time Bitcoin transaction
monitoring via WebSockets
Decision.AI — Data science and decision intelligence platform
• Built the complete frontend from scratch using React, Material UI, D3, and Cypress — including complex interactive
data visualisations and multi-step dashboard views
Multiregnskab — Accounting SaaS for Danish holding companies
• Led legacy codebase refactoring and new feature development in React; built SEO-optimised landing page and
implemented long-polling for live accounting sync across multi-user sessions

EDUCATION
B.Sc. Applied Mathematics (Software Development)
Odesa I.I. Mechnikov National University, Faculty of Systems Engineering · 2016 – 2020

LANGUAGES
English — Upper Intermediate · Ukrainian — Native · Russian — Native