Nikita

NIKITA KORCHEMNIY
BACKEND ENGINEER
+0678767621 KorchemniyNikita [відкрити контакти](див. вище в блоці «контактна інформація»)
Odessa @worflersst KorchemnyiNikita

SUMMARY

My name is Korchemnyi Nikita. I am a backend developer focused on building scalable, testable, and fault-tolerant
applications using NestJS, with an emphasis on clean architecture, reliable APIs, and well-thought-out system design that
is easy to maintain and extend. I also work with application metrics and monitoring, handle deployment processes,
configure Nginx, and manage secure access to databases and VPS infrastructure.

SKILL HIGHLIGHTS

Tools: Git, Jira, Prettier, ESLint, Doppler, Swagger Databases: Postgres, MySql, MongoDB, Redis

Backend: TypeScript, Node.js, NestJS, Express.js, Prisma DevOps & Infrastructure: Docker, Docker
ORM, REST API, WebSockets (Socket.io), Zod, Authentication Compose, Docker Swarm, Nginx, VPS, CI/CD
(JWT, OAuth) Caching (Redis), BullMQ, Cron. (GitHub Actions), Zero-downtime deployments,
Secrets Management.
Architecture: 3-Tier, Hexagonal Architecture, DDD, Unit of Monitoring: Prometheus, Grafana, Node
Work, SOLID
Exporter
Frontend: Html, Css, Scss, Tailwind, Typescript, React, Testing: Jest, Testcontainers (Unit, Integration,
Redux-Toolkit, React-Router-Dom, React-Hook-Form, i18n
E2E)

LANGUAGE
English–B1(intermediate,inprogress),Ukrainian-native

EXPERIENCE
QuantaTechnology—Web3 Backend Engineer Sep.2024 – Present
 Backend Architecture & Core Systems
• Designed and implemented scalable backend architecture using NestJS with Hexagonal Architecture and DDD principles.
• Developed core modules: User, Auth, Profile, Crypto, Admin (KYC moderation), and KYC (document submission).
• Built a custodial crypto wallet system: automatic wallet creation for verified users, encrypted private key storage, and secure key
management via Doppler.
• Implemented Admin module for document verification workflow (approve/reject, comments, moderation flow).
 Real-time & Async Processing
• Implemented real-time crypto price updates using WebSockets (Socket.io) with optimized event emission (only changed data).
• Built resilient integrations with external APIs using BullMQ (retry strategies, backoff, background jobs).
• Implemented scheduled jobs (Cron) for periodic synchronization of cryptocurrency prices.
 Performance & Data Management
• Introduced Redis caching layer to optimize high-load queries and reduce database pressure.
• Applied Unit of Work (UoW) pattern for transactional consistency.
• Structured database environments (dev/prod) with secure access control and isolation.
 Monitoring & Observability
• Implemented monitoring stack using Prometheus, Grafana, and Node Exporter:
– Application metrics (CPU, Event Loop Lag, Memory, Heap)
– VPS metrics (CPU load, RAM, disk usage)
• Added health-check endpoints for container and service availability monitoring.
 Infrastructure & DevOps
• Configured Nginx for HTTP and WebSocket support.
• Deployed services via Docker Swarm with zero-downtime rolling updates.
• Secured database via internal Docker networking (no public exposure).
• Implemented CI/CD pipelines in GitHub Actions: linting, automated tests, secrets management (Doppler), and continuous deployment.
 API & Validation
• Fully documented API using Swagger (OpenAPI).
• Used Zod for runtime validation and type-safe schema definitions.
• Designed flexible endpoints for dynamic system configuration (e.g., asset management, media updates).
 Testing & Reliability
• Covered system across the testing pyramid: unit, integration, and e2e tests.
• Used Testcontainers for isolated and production-like integration testing environments.

TechStack: TypeScript, Nest.js, Prisma.orm, Postgresql, Redis, BullMq, WebSockets(Socket.io), AWS(S3), Swagger, Zod, Cron,
Jest, TestContainers, Docker, Docker Swarm, Nginx, VPS, Grafana, Promethus, CI/CD.