Назарій

Nazariy Belelya
Full-Stack Software Engineer
Ukraine / Remote

[відкрити контакти](див. вище в блоці «контактна інформація»)

GitHub: github.com/bellzar7

LinkedIn: link

Node.js | NestJS | Next.js | PostgreSQL | Neo4j | Microservices | Cloud & DevOps

EDUCATION LANGUAGES
Bachelor’s Degree — Software Engineering
 English — B1

Ukrainian National Forestry University (2016 – Ukrainian — Native
2022)

Computer Academy OKTEN School (2022 – 2023)

PROFESSIONAL SUMMARY
Senior Full-Stack Software Engineer with 4+ years of experience building scalable web platforms, internal
systems, and real-time applications for product and service companies.


Strong backend focus with hands-on experience in API design, authentication and authorization, real-time
communication, complex data modeling, and system architecture.


Experienced in Node.js, NestJS, Next.js, SQL and NoSQL databases (PostgreSQL, MongoDB, Neo4j), microservice-
oriented and modular architectures, cloud infrastructure, containerization, and CI/CD pipelines.


Comfortable owning features end-to-end — from architectural decisions and backend implementation to frontend
integration, deployment, and production support.

Backend & Architecture Databases & Data Modeling
Node. js, NestJS, Express
P ostgreSQL, MySQL (schema design, indexing,
REST API design, versioning, validation, layered migrations, optimization)

and modular architectures
MongoDB (document modeling, aggregation when
Authentication & authorization (JWT, OAuth, RBAC, applicable)

refresh tokens)
Neo4j (graph modeling, relationships, complex
Real-time systems (WebSockets, presence tracking, Cypher queries)

notifications)
Supabase (auth, storage, database integration)

Event-driven architecture (Kafka, background jobs, Data consistency, integrity rules, query
async workflows)
performance tuning
Microservices & distributed components (service
boundaries, communication patterns)

Service-to-service communication (REST, gRPC)

API contracts and backward compatibility

System design, scalability, performance and
reliability optimization

Frontend DevOps & Infrastructure
React , Next.js (SSR/SSG, client/server separation)
D ocker, Docker Compose (containerized
TypeScript
environments)

State management (Redux Toolkit, pragmatic server- Kubernetes (basic orchestration, deployments,
state patterns)
rollouts)

UI systems (Tailwind CSS, Material UI)
Linux servers (Nginx, PM2, monitoring,
Responsive, accessible interfaces and API-driven UI troubleshooting)

integration CI/CD pipelines (GitLab CI)

Cloudflare Workers & edge computing

AWS S3 / object storage

Vercel, Heroku, self-hosted servers

Engineering Practices
OOP, SOLID, clean and maintainable architecture

Code reviews, mentoring, technical ownership

Agile delivery (Scrum / Kanban)

Git-based workflows and collaborative development
PROFESSIONAL EXPERIENCE

Full-Stack Software Engineer — MARK IT
2022 – 2024

Led development of production-grade web applications with a strong focus on backend architecture, scalability, and system reliability.

Key contributions & impact:

Designed and implemented backend architectures using Node.js, Express, and NestJS

Built secure authentication and authorization systems (JWT, role-based access control)

Designed relational and NoSQL data models (PostgreSQL, MongoDB)

Integrated third-party services (payments, email delivery, file storage)

Improved API performance and reduced response times through query optimization and indexing

Mentored junior developers, conducted code reviews, and enforced engineering best practices

Took ownership of deployment pipelines, containerization, and production stability

Project: Crowdfunding Platform (Hidegram)
Product company | Team size: 7 | Duration: 20 months

Tech Stack:

Node.js, Express, TypeScript, PostgreSQL, AWS S3, Next.js, Redux Toolkit, Material UI

Responsibilities & results:

Designed backend architecture and relational database schema

Implemented secure JWT-based authentication and authorization flows

Integrated payment system (Fondy) and email delivery (SendGrid)

Built file upload and storage pipeline using AWS S3

Developed admin dashboard and user management functionality

Deployed backend and frontend to production environments

Ensured system stability and scalability under real user load

Full-Stack Software Engineer — OX Company
2024 – 2025

Designed and implemented a complex legal communication platform with real-time features and strict role-based access control.

Key achievements:

Designed backend architecture using NestJS with clear module and service boundaries

Implemented graph-based data modeling with Neo4j to handle complex relationships between users, lawyers, cases, and conversations

Built real-time messaging system using WebSockets with presence tracking

Implemented role-based logic for clients, lawyers, and administrators

Integrated Kafka for event-driven notifications and background processing

Worked with distributed components and microservice-oriented patterns where appropriate

Used Supabase for authentication and file storage

Implemented edge APIs using Cloudflare

Worked with inter-service communication patterns, including REST and gRPC, focusing on clear API contracts and system boundaries

Improved system performance, data consistency, and maintainability by refactoring backend logic

Front-End Developer — Znaesh Agency
2020 – 2022

Key achievements:

Developed 100+ landing pages and client projects

Worked with React, Angular, and Vue

Built a strong foundation in frontend architecture and UI development

Collaborated closely with designers and backend developers