Zhila

Bohdan Zhyla
Backend Engineer (Node.js / NestJS / TypeScript)
Kyiv, Ukraine • [open contact info](look above in the "contact info" section) • [open contact info](look above in the "contact info" section) • [open contact info](look above in the "contact info" section) •
github.com/macrocephalus • t.me/macro_ai

PROFESSIONAL SUMMARY
Backend engineer with 7+ years of commercial experience in JavaScript, TypeScript, Node.js and NestJS.
Shipped backends for consumer apps reaching 10M+ users, sole backend owner of a live Google Play
product (4.5★, 50K+ downloads), and most recently built and supported enterprise POS and self-checkout
software for one of Ukraine's largest retail networks. Strong in high-load and real-time systems,
PostgreSQL, observability, and applied AI/LLM integration — including bringing AI agents into production
engineering workflows.

CORE COMPETENCIES
Backend Development · Node.js / NestJS · REST & GraphQL API Design · WebSockets / Socket.IO ·
PostgreSQL & MongoDB · Message Queues (BullMQ, RabbitMQ) · High-Load & Real-Time Systems ·
AI / LLM Integration · Observability & Monitoring · Third-Party Integrations · Code Review · Agile /
Scrum

TECHNICAL SKILLS
Languages: TypeScript, JavaScript (ES5/ES6, Node.js)
Backend: NestJS, Express, REST, GraphQL, modular architecture, SOLID, API design
Databases: PostgreSQL (raw SQL & TypeORM), MongoDB, Firestore — data modeling, indexing, query
optimization
Real-time: Socket.IO, WebSockets, real-time TTS, messaging systems
Queues & jobs: BullMQ (Redis-backed job queues, background processing), RabbitMQ
AI engineering: Multi-provider LLM integration (Vercel AI SDK: OpenAI, Anthropic, Google, Groq, xAI,
DeepSeek), RAG pipelines, real-time TTS, AI agents in dev workflows, prompt engineering
Cloud & DevOps: AWS (Auto Scaling, EC2), Google Cloud, DigitalOcean, Docker, Linux, CI/CD
Observability: VictoriaMetrics, Prometheus, custom metrics, business-metrics instrumentation
Also: Vue 3, Next.js for full-stack product work

PROFESSIONAL EXPERIENCE

Foodtech (Fozzy Group / Silpo) — Developer (JavaScript)Aug 2025 – Jun 2026
Enterprise retail software: POS systems and self-checkout kiosks running on ~1,000 terminals across a
national supermarket chain. Stack: JavaScript (ES5/ES6), PostgreSQL, Linux.
• Developed business logic and features for a large-scale POS and self-checkout application — including
loyalty-program processing used in day-to-day store operations across the network — working across both
backend and the frontend part of the POS client.
• Maintained and supported the existing production system: navigating a large legacy codebase, extending
complex domain logic, and resolving issues in software running live in stores.
• Delivered monitoring and business-metrics tasks on VictoriaMetrics/Prometheus — designed per-terminal
labeling to prevent timeseries collisions across a fleet of ~1,000 POS terminals — enabling real-time
transparency into POS operation for engineering and business teams.
• Adapted the project for AI agents and introduced an AI code-review agent into the team's workflow, tuned for
the project's codebase — adding an automated review layer alongside human code review.
• Contributed across the full delivery cycle within an Agile/Scrum process — task estimation,
business-requirements discussions with stakeholders, third-party integrations, and regular code reviews.
Reference letter from team lead available on request.

Iridescent Studios — Node.js Backend DeveloperOct 2021 – Jun 2025
• Engineered backend services for consumer mobile, VR and AR apps with a combined 10M+ users —
designed and built APIs for the apps and their in-app chat features, admin panels for content and user
management, real-time communication over WebSockets/Socket.IO, and server-side integration with Unity.
 • Mentored two junior developers — code reviews, architectural guidance and onboarding — and coordinated
day-to-day across frontend, backend and DevOps engineers to align API contracts, releases and
infrastructure changes.
• Led performance optimization of existing server solutions — profiling and improving response times and
resource usage across the studio's backend services.
• Introduced spec-driven development (OpenSpec) into one of the studio's projects, structuring feature work
around explicit specifications.
• Deployed and operated backend services in production, including infrastructure on DigitalOcean and AWS.
GIBBON Balance App — sole backend developer • Google Play: 4.5★ (533 reviews), 50K+ downloads, live in 2026
• Designed and built the entire backend for an international fitness product (GIBBON Slacklines, Germany)
with a React Native client: user accounts, progress and skill tracking, a rewards engine (coins, merit badges,
balance points), guided-video content delivery and social sharing — owning the full API contract for the
mobile team, with privacy-compliant personal-data handling.
Multi-provider AI chat
• Built an AI chat backend on NestJS unifying six LLM providers (OpenAI, Anthropic, Google, Groq, xAI,
DeepSeek) behind one interface via the Vercel AI SDK, with WebSocket-based streaming and tool calling —
the product could route or swap models with no client changes.
Game infrastructure
• Designed a server-side load balancer for a real-time multiplayer game on AWS Auto Scaling (one game
process per CPU core, up to 30 rooms per process) — auto-spawning processes and provisioning servers as
cores saturate, keeping matches available under peak load.
• Integrated the WinZO gaming platform (match-result persistence, game configuration, server-side game
logic).
Conversational VR experience (RAG + TTS)
• Built the backend for a VR experience letting users hold spoken conversations with a book's author: a RAG
pipeline grounding LLM responses in the book's content, paired with a real-time text-to-speech server for
natural in-VR voice interaction.
GoodZoo — Full-Stack Developer (Node.js)Jan 2019 – Nov 2021
• Built and maintained Node.js web applications; designed and optimized PostgreSQL schemas.
• Delivered payment-gateway and CMS integrations; built server-side solutions for mobile apps with Unity
integration.
• Migrated parts of a legacy PHP codebase to Node.js, consolidating the stack and improving maintainability.

SELECTED PROJECTS
• Technical writing — author of articles on AI code-review security (prompt injection, fail-closed principles),
multi-provider AI architecture, and spec-driven development (OpenSpec).
• Alias Party (Tauri 2 + Vue 3) and Queen's Gambit (Ionic 7 + Vue 3) — cross-platform mobile games, original
game-design specs.
• Mental-health platform (Next.js) and a Slack-style real-time team messenger.

EDUCATION
Kyiv National Economic University — Specialist & Bachelor, Computer Science (2012–2018)
College of Industry, Economics and Law — Software Engineering (2009–2012)

CERTIFICATIONS & LANGUAGES
Google Cloud: Create & Manage Cloud Resources; Foundational Infrastructure Tasks; Load Balancing on
Compute Engine; Develop Your Google Cloud Network — verified badges
Languages: Ukrainian — Native; English — Pre-Intermediate (technical documentation, written communication)