Stas

STAS TROTSENKO
SENIOR FULL-STACK ENGINEER
React | React Native | TypeScript | Node.js | NestJS
Kyiv, Ukraine | Remote Worldwide | B2B Contractor
[відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація»)

PROFESSIONAL SUMMARY
Senior Full-Stack Engineer with 6 years of commercial software development experience and deep expertise in React,
React Native, TypeScript, Node.js, and NestJS. Experienced in delivering scalable web and mobile products across
frontend interfaces, API integrations, data flows, real-time functionality, offline-first workflows, resilient integrations, and
production support for SaaS, logistics, and enterprise platforms. Strong background in frontend architecture, full-stack
collaboration, application performance, system reliability, third-party integrations, authentication, and end-to-end feature
ownership. Capable of translating business requirements into maintainable technical solutions, collaborating across
Product, Design, QA, Backend, and DevOps teams, and supporting features throughout their complete lifecycle from
architecture and implementation to release, monitoring, and production optimization. Experienced in mentoring engineers,
conducting code reviews and technical interviews, and improving engineering standards.

WORK EXPERIENCE
SENIOR FRONTEND DEVELOPER
FleetAir International Kft | Hungary - Remote
Nov 2023 - Jun 2026
- Owned the delivery of business-critical functionality for a high-load logistics platform, working across frontend architecture, API
integrations, data processing, and production reliability.
- Collaborated with backend engineers to design and refine API contracts, data models, request flows, and error-handling
strategies for complex logistics operations.
- Led application migration and architectural restructuring initiatives that improved maintainability, reduced technical complexity,
and enabled faster feature delivery.
- Implemented caching, offline support, synchronization, retry mechanisms, and resilient network handling to maintain stable
behavior under unreliable connectivity conditions.
- Developed complex data-driven workflows integrating backend services, real-time updates, business validation rules, and
user-facing interfaces.
- Optimized end-to-end performance by improving rendering logic, data transformation, request coordination, state management,
and communication with backend services.
- Investigated and resolved production issues across frontend logic, API communication, cached data, and user workflows.
SENIOR FRONTEND DEVELOPER
BeSocial Studio | Ukraine
Jul 2021 - Oct 2023
- Owned frontend architecture and end-to-end implementation of product functionality for a scalable SaaS platform.
- Built a real-time, data-driven application from the ground up, integrating user interfaces with backend APIs, live messaging,
dynamic updates, and synchronized application state.
- Collaborated with backend engineers to define API contracts, data structures, authentication flows, and real-time
communication patterns.
- Developed reusable integration mechanisms for connecting new partners and external services, simplifying onboarding and
supporting business growth.
- Implemented complex client-side data processing and synchronization logic for large data volumes and frequently changing
real-time information.
- Optimized communication between frontend and backend services, reducing unnecessary requests and improving overall
application responsiveness.
MIDDLE FRONTEND DEVELOPER
Career Karma | USA - Remote
Jan 2020 - Jun 2021
- Developed product features by implementing React interfaces and integrating them with backend APIs and external services.
- Collaborated with backend engineers to align frontend data requirements with API responses, validation rules, authentication
flows, and error-handling behavior.
- Integrated third-party APIs and platform services to extend product functionality and support new business requirements.
- Implemented client-side data transformation, state management, asynchronous request handling, and user-facing validation.
- Improved application performance by optimizing rendering, request flows, data loading, and interaction with backend services.

TECHNICAL SKILLS
Languages: JavaScript (ES6+), TypeScript, HTML5, CSS3, SCSS
Frontend: React, Next.js, Storybook, shadcn/ui, Material UI, Bootstrap, Tailwind CSS
Mobile: React Native, Expo, Reanimated, Native Modules, Push Notifications
Backend: Node.js, NestJS, Express.js, Fastify
State Management: Redux Toolkit, Redux Thunk, Redux Saga, RTK Query, TanStack Query, MobX,
MobX-State-Tree, Zustand
APIs and Realtime: REST API, GraphQL, Apollo Client, WebSockets, Socket.io, Axios, Webhooks
Databases and Data Access: PostgreSQL, SQL, MongoDB, Redis, Prisma, TypeORM
Architecture and Messaging: Microservices, Event-Driven Architecture, Caching, BullMQ, Worker Queues
Cloud and DevOps: AWS, Docker, Kubernetes, Vercel, GitHub Actions, Jenkins, CI/CD
Firebase: Authentication, Firestore, Cloud Messaging, Analytics
Authentication and Security: OAuth 2.0, JWT, AWS Cognito, Okta
AI and Automation: AI/LLM Integrations, RAG, AI Workflows, Document Generation
Payments: Stripe, Chargebee
Testing and Quality: Jest, React Testing Library, Playwright, Puppeteer, Maestro, Mock Service Worker, Code
Review
Build and Performance: Vite, Webpack, Babel, Lighthouse, Code Splitting, Lazy Loading, Bundle Analyzer
Monitoring: Sentry, Google Analytics
Mobile Release: TestFlight, App Store, Google Play
Tools and Methodologies: Git, GitHub, Cursor, VS Code, Xcode, Android Studio, Postman, Figma, Jira, Confluence,
Notion, Agile, Scrum

EDUCATION
National Aerospace University "Kharkiv Aviation Institute"
Aerospace and Rocket Engineering
Kharkiv, Ukraine

LANGUAGES
Ukrainian - Native
English - Upper-Intermediate