Stas

STAS TROTSENKO
FULL-STACK ENGINEER | React, Next.js & Node.js
Kyiv, Ukraine | Remote | [open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | LinkedIn
PROFESSIONAL SUMMARY
Full-Stack Engineer with 6+ years of software development experience and deep expertise in frontend engineering. Builds B2B and
B2C SaaS products across web, mobile, and backend systems using React, Next.js, TypeScript, Node.js, and NestJS. Experienced in
frontend architecture, accessible and data-intensive interfaces, API design, real-time and event-driven workflows, cloud delivery,
automated testing, and production support. Focused on transforming complex business requirements into scalable, maintainable
solutions while taking ownership from implementation through production.
CORE SKILLS
Frontend: React, Next.js, TypeScript, JavaScript, Redux Toolkit, Zustand, TanStack Query, Apollo Client, React Hook Form, Tailwind
CSS, MUI, Accessibility, Virtualization

Backend and APIs: Node.js, NestJS, Express.js, REST APIs, GraphQL, OpenAPI, Zod

Messaging and Real-Time: Kafka, RabbitMQ, WebSocket, Socket.IO, SSE, WebRTC

Mobile: React Native, Expo, Reanimated, Push Notifications

Data and Persistence: PostgreSQL, MongoDB, Redis, Supabase, Prisma, SQL, Data Modeling, Indexing, Transactions, Caching

Cloud and Delivery: AWS, Docker, GitHub Actions, CI/CD

Testing: Jest, Playwright, React Testing Library, Unit Testing, Integration Testing, E2E Testing

Observability and Performance: Sentry, Structured Logging, Performance Profiling, Web Vitals, Incident Response

Architecture and Engineering: System Design, Real-Time Systems, Event-Driven Architecture, API Design, Idempotency,
Resilience, Multi-Tenancy, Technical Ownership, Code Review, Mentoring

AI-Assisted Development: Claude Code, Cursor
PROFESSIONAL EXPERIENCE
Senior Full-Stack Engineer | Nov 2023 - Jun 2026
Fleet Air International Kft.
Stack: React, Next.js, TypeScript, Zustand, TanStack Query, Apollo Client, Node.js, NestJS, REST APIs, GraphQL,
Supabase, Prisma, Redis, Kafka, RabbitMQ, AWS

Testing and Operations: Jest, React Testing Library, Playwright, Sentry
D esigned and implemented GraphQL and REST workflows, documenting API contracts with OpenAPI and applying
Zod-based validation, data transformation, error handling, and integration with frontend application flows.

Owned full-stack delivery of business-critical functionality across data-intensive React and Next.js interfaces,
Node.js and NestJS services, API integrations, AWS-hosted environments, and production support.

Built real-time and event-driven workflows using Kafka, RabbitMQ, and SSE, connecting asynchronous backend
processing with operational interfaces and rapidly changing client-side state.

Developed resilient client-server data flows with Redis-backed caching, synchronization, retry mechanisms, offline
handling, and recovery strategies for unreliable network conditions.

Led architectural refactoring and migration initiatives across frontend and backend layers, simplifying integration
and data-management patterns while making feature delivery safer and more maintainable.

Investigated and resolved production issues using Sentry across APIs, asynchronous workflows, cached data, and
service dependencies, improving system stability and incident diagnosis.

Built automated test coverage with Jest, React Testing Library, and Playwright across frontend components,
integrations, and critical end-to-end workflows.

Senior Frontend Developer | Jul 2021 - Oct 2023
BeSocial Studio
Stack: React, Next.js, TypeScript, Redux, Redux-Saga, Redux Thunk, REST APIs, WebSocket, Socket.IO, WebRTC,
MUI, Tailwind CSS, React Hook Form, Yup, Docker

Testing: Jest, React Testing Library
D elivered core TypeScript functionality integrating REST APIs, WebSocket and Socket.IO messaging, WebRTC
communication, third-party services, and synchronized application state.

Led frontend architecture and built the core SaaS application from the ground up, establishing a scalable
foundation for real-time and data-intensive product workflows.

Designed reusable frontend patterns for authentication, schema validation, API integration, real-time updates, and
resilient error handling, reducing duplicated implementation and simplifying new partner integrations.

Optimized data-intensive interfaces through virtualization, efficient request flows, data transformation, and client-
side state synchronization, improving rendering performance and maintainability for large, frequently changing
datasets.

Built unit and integration test coverage with Jest and React Testing Library across reusable components,
application flows, and API integrations.

Full-Stack Engineer | Web & Mobile | Jan 2020 - Jun 2021
Career Karma
Stack: React, React Native, Expo, Reanimated, JavaScript, Node.js, Express.js, REST APIs, MongoDB, AWS, GitHub
Actions, Jest, React Testing Library, Sentry
B uilt and integrated REST APIs covering authentication, validation, data processing, MongoDB persistence, and
consistent error handling across multiple product surfaces.

Delivered end-to-end product functionality across React web applications, React Native and Expo mobile clients,
and Node.js and Express.js backend services deployed on AWS.

Developed reusable application flows and shared business logic across web and mobile clients, integrating
backend services and third-party platforms.

Implemented mobile functionality with React Native, Expo, and Reanimated, including push notifications, animated
interactions, and integrations with native platform capabilities.

Improved client- and server-side performance through API request optimization, code splitting, efficient data
loading, and frontend rendering improvements.

Built unit and integration test coverage with Jest and React Testing Library across shared application logic, user-
facing components, and API-integrated flows.

Supported production releases through GitHub Actions-based CI workflows and used Sentry across web, mobile,
and backend layers to diagnose integration issues and improve overall system stability.

EDUCATION
M. E. Zhukovsky National Aerospace University “Kharkiv Aviation Institute”: Bachelor of Science in Engineering

Design, 2016 - 2021

SkillUp: Frontend Development Program, 2019 - 2020

LANGUAGES
English: Intermediate (B1) | Ukrainian: Native