Олександр

Oleksandr Zabolotniy
Fullstack / Backend Developer
Remote, Dublin · English B1 · github.com/Oleksandr004 · t.me/sunsanych04 · [відкрити контакти](див. вище в блоці «контактна інформація») · [відкрити контакти](див. вище в блоці «контактна інформація»)

SUMMARY
Fullstack developer with ~1 year of commercial experience across multiple product teams. Specialized in Node.js / NestJS backend and React / Next.js frontend. Built and shipped a production-grade uptime monitoring system (real-time WebSocket, BullMQ queues, Telegram notifications, Docker, AWS). Comfortable owning a full vertical — from database schema to deployed UI.
EXPERIENCE
Fullstack Developer (Contract) · Mafia World Game · mafia.events
Mar 2025 – Apr 2025 | Remote
Telegram Bot & Admin Panel development for a live social gaming product with active international user base.
• Built targeted broadcast system for super-admins: send messages to specific clubs, cities, countries or all users; supports text, photos, videos and media groups up to 10 files
• Implemented automatic group binding — bot saves Telegram chat ID on add or via /bind_ID command, stored in PostgreSQL
• Fixed critical bug: bot freeze when moderator blocked the bot — refactored notification flow to skip failed recipients, guaranteed DB writes before notifications
• Implemented extra seats system: 2 slots over session limit with +30%/+50% price surcharge, dynamic player count display, admin-panel indicators
• Built automated reminder system: notifications at 6h / 3h / 30min / 10min before game start, with deduplication via reminders_sent flag and full RU/UK/EN localization
• Developed music order feature for night phase: online/offline payments, staff earnings auto-recorded as club debt, super-admin controls for pricing and staff percentage
• Fixed locale bug — bot now correctly initializes for users with any Telegram language setting
• Deployed and maintained all updates on production server via SSH
Fullstack Developer (Contract) · Energy Dashboard · Confidential Client
Aug 2024 – Feb 2025 · 7 months | Remote
Full-cycle development of an energy monitoring platform integrated with Censo GraphQL API. Team: PM, Designer, 2 Developers.
• Built role-based admin panel (Admin / User) with full user CRUD, module activation per user, and API key assignment
• Integrated Censo GraphQL API for real-time energy metrics: production, consumption, feed-in, EV charging, CO₂, gas
• Implemented JWT auth (access + refresh tokens) with httpOnly cookies and password reset via Nodemailer
• Built geolocation-based data localization and weather API integration (OpenWeatherMap)
• Developed user profile with photo upload (Cloudinary), responsive dashboard with MUI + Tailwind CSS
• Stack: React 19, TypeScript, Vite, Express.js, MongoDB, Mongoose, JWT, Nodemailer, Axios
Frontend / Fullstack Developer · Freelance Projects
2023 – present | Remote
• Uptime Sentinel — production fullstack monitoring system: NestJS 11, Next.js 16, PostgreSQL, Redis, BullMQ, WebSocket (socket.io), JWT access/refresh, Telegram Bot, Docker, GitHub Actions CI/CD, AWS. Features: real-time status updates, latency analytics (24h/7d/30d), incident log, CSV/PDF export
• Furniture e-commerce store — Next.js App Router + MongoDB + Payload CMS (in progress), TypeScript, auth, cart, filters, pagination, delivery flow, Framer Motion animations, Vercel deploy
• Office building dashboard — energy consumption, CO₂ tracking, weather and generation analytics (React + Recharts + Tailwind)
• Multi-page marketing websites — responsive HTML/CSS/JS layouts, cross-browser, mobile-first
TECHNICAL SKILLS
Backend
Node.js, NestJS 11, Express.js, Prisma 7, TypeORM, JWT (access/refresh), Passport.js, BullMQ, WebSocket / socket.io, Swagger, Nodemailer, Telegraf, node-cron, Stripe (partial)
Frontend
React 19, Next.js 16 (App Router, SSR/SSG/ISR), TypeScript, Zustand, Redux Toolkit, React Hook Form + Zod, Tailwind CSS, SCSS Modules, Radix UI, shadcn/ui, Framer Motion, Recharts, FSD architecture
Databases
PostgreSQL, MongoDB, Redis · Prisma ORM, Mongoose · basic query optimization, indexes
DevOps
Docker, docker-compose, GitHub Actions (CI/CD), Vercel, Render, AWS (EC2, S3), SSH, pnpm
Testing
Jest, Vitest (unit), Cypress, Playwright (E2E)
KEY PROJECTS
Uptime Sentinel
Fullstack uptime & latency monitoring. NestJS + Next.js + PostgreSQL + Redis + BullMQ + WebSocket + Docker + CI/CD + AWS. Real-time dashboard, Telegram alerts, incident log, CSV/PDF export.
Furniture E-commerce
Next.js App Router + Payload CMS + MongoDB + TypeScript. Auth, cart, filters, pagination, delivery, animations. Vercel deploy.
EDUCATION & SELF-DEVELOPMENT
Self-taught developer · Continuous learning via official docs, open source projects, and practical project work. Active on GitHub.
• Core focus areas: system design, NestJS internals, SQL optimization, microservices patterns
• English: B1 — reading technical documentation, written communication with international teams