Давид

David Kachur-Shefer
Full Stack Developer
Mukachevo, Ukraine | [відкрити контакти](див. вище в блоці «контактна інформація») | [відкрити контакти](див. вище в блоці «контактна інформація») | Telegram: @Scar_lex
GitHub | LinkedIn | Portfolio

PROFILE SUMMARY
Full Stack Developer with 3+ years of commercial experience building production web applications, from
responsive UIs to scalable APIs, database architecture and cloud integrations. Strong in the React / Next.js
ecosystem on the front end and NestJS, GraphQL and PostgreSQL on the back end. Hands-on experience
with AI integrations (Claude, OpenAI, MCP), real-time systems and multi-tenant SaaS architecture. Focused
on clean, type-safe code, performance and delivering features end-to-end in Agile teams.

PROFESSIONAL SKILLS
• End-to-End Feature Development: Deliver features from database schema and API to UI and
deployment
• System Design: Design multi-tenant SaaS architecture, GraphQL APIs and data models for scalable
products
• AI Integration: Build LLM-powered features, streaming chat and agent workflows with external tools via
MCP
• Performance Optimization: Improve load time, bundle size and API response time with measurable
results
• Code Review & Quality: Review teammates' pull requests, enforce coding standards and keep
codebases type-safe and maintainable
• Agile Collaboration: Work in Scrum/Kanban teams alongside designers, QA and product managers

TECHNICAL SKILLS

Languages JavaScript, TypeScript, SQL
Frontend React 19, Next.js (App Router, SSR/SSG), Redux, Zustand, React Hook Form,
Svelte & SvelteKit, Apollo Client, SWR
Styling & UI HTML5, CSS3, SCSS, Tailwind CSS, Radix UI, Shadcn/ui
Backend Node.js, NestJS (modules, guards, interceptors, DTO validation), Express.js,
REST API design, GraphQL (Apollo Server, resolvers, subscriptions),
WebSockets, streaming responses (SSE)
Auth & Security JWT, OAuth 2.0, AWS Cognito, role-based access control, multi-tenant data
isolation
Databases & ORM PostgreSQL, MySQL, Prisma ORM (schema design, migrations, relations),
query optimization
AI & Integrations Claude API (Anthropic), OpenAI API, Model Context Protocol (MCP), Microsoft
Graph API, LLM streaming
Cloud & Infrastructure AWS (S3, Cognito, CloudWatch), Turborepo (monorepo), Bun
Tools & Libraries Git, GitHub, GitLab, gql.tada, Zod, nuqs, Axios

WORK EXPERIENCE

Full-Stack Developer | Hatkom Nov 2025 – Jun 2026
• Built and maintained a full-stack SaaS platform using Next.js (App Router), NestJS and GraphQL (Apollo
Server/Client)
• Implemented a real-time AI chat with streaming responses via GraphQL subscriptions, integrating Claude
(Anthropic) and OpenAI GPT models
• Built Microsoft Graph API (Outlook) integration to give AI agent workflows access to user email
• Designed a type-safe GraphQL client with gql.tada, fragment composition and automatic type generation

• Implemented multi-tenant architecture with database-level data isolation using PostgreSQL and Prisma
ORM
• Integrated Model Context Protocol (MCP) to connect external AI platforms with internal tooling
• Built an automated data feed parser with AI-powered classification and mapping to internal data
structures

Frontend Developer | PRAI Mar 2025 – Aug 2025
• Built 20+ responsive pages and features with React and Next.js, moving key pages to SSR/SSG
• Improved page load time by ~30% through code splitting, lazy loading and image optimization
• Created a reusable component library that cut new-feature UI development time by ~25%
• Integrated REST APIs and third-party services (payments, analytics, maps) into the product
• Raised Lighthouse accessibility score to 90+ by fixing semantics, contrast and keyboard navigation

Full-Stack Developer | Training Club Sep 2024 – Jan 2025
• Developed the client platform end-to-end with React on the front end and Node.js on the back end
• Designed 15+ REST API endpoints backed by PostgreSQL and Prisma ORM, including schema design and
migrations
• Implemented authentication and authorization with JWT and OAuth (Google sign-in) and role-based access
• Reduced average API response time by ~40% through query optimization, indexing and pagination
• Worked closely with the designer to improve UI/UX of key user flows

Frontend Developer | Global Partner Soft May 2023 – Jun 2024
• Developed responsive web applications with React and Tailwind CSS for 5+ client projects
• Built a shared design system of 30+ reusable components, keeping UI consistent across projects
• Reduced bundle size by ~20% by removing unused dependencies and introducing lazy loading
• Integrated third-party libraries and APIs (forms, charts, payment and analytics SDKs)
• Ensured cross-browser compatibility across Chrome, Safari, Firefox and mobile browsers

KEY PROJECTS
AI-Powered Multi-Tenant SaaS Platform (Hatkom) — Full-Stack Developer
• Real-time AI assistant with streamed Claude and OpenAI responses over GraphQL subscriptions
• AI agents with access to Outlook email via Microsoft Graph API and external tools via MCP
• Tenant-isolated data model in PostgreSQL with Prisma ORM
• Tech: Next.js, NestJS, GraphQL, Apollo, gql.tada, PostgreSQL, Prisma, AWS (S3, Cognito, CloudWatch),
Turborepo
Client Platform & Auth Service (Training Club) — Full-Stack Developer
• Authentication module with JWT access/refresh tokens, Google OAuth sign-in and role-based permissions
• Typed REST API layer with request validation and a normalized PostgreSQL schema managed through
Prisma migrations
• Tech: React, Node.js, Express.js, PostgreSQL, Prisma, JWT, OAuth

EDUCATION

Master's Degree in Computer Science Sep 2025 – Jun 2027 (expected)
Uzhhorod National University

Bachelor's Degree in Computer Science Sep 2021 – Jun 2025
Uzhhorod National University

LANGUAGES
Ukrainian English
Native Upper-Intermediate (B2)