Михайло

Michael Katskiy
Full-Stack Developer
Kharkiv, Ukraine (Remote, EET)
[open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section) | github.com/haggifer | [open contact info](look above in the "contact info" section)

Summary
Full-stack developer with 5+ years of commercial experience, working in TypeScript across React/Next.js front ends and
Node.js services on GCP, AWS and Firebase. Used to owning features end to end in small, flat teams: goal-level requirements
through data modeling, architecture and technology selection to release, monitoring and production support. Recent work has
centered on AI-driven products and security compliance, alongside full-stack side projects (AdLens, Likely Weather).

Experience
VisCap Media (VisCap.ai) Mar. 2024 – Jul. 2026
Full-Stack Developer Remote
• Developed and maintained the core web application of an AI-driven video advertising platform used by dozens of

companies and ad agencies, handling thousands of ads and hundreds of thousands of ad elements, using TypeScript,
Next.js, React, Zustand, TanStack Query (React Query), Formik and Ant Design.
• Collaborated in a flat team of 5 to 7 engineers, working in Kanban and later in Scrum.

• Added features to the product’s companion client apps, a React Native (iOS/Android) mobile app and an Electron

desktop app for uploading and syncing media content, sharing Firebase and Typesense with the web app.
• Designed and evolved Firestore data models, security rules and production data migrations for collections exceeding

500,000 documents with a Typesense search layer on top, and co-led the platform’s migration from Firestore to
MongoDB.
• Built a concurrent, recursive Firestore collection iterator with bounded parallelism for production migrations, cutting

processing time by up to 95% on collections of 100,000+ documents and enabling near-zero-downtime migrations; since
published on npm as firestore-iterator.
• Delivered a file-upload security pipeline for CASA SAQ / Google Drive extended-access compliance, passed on the first

attempt with no issues raised: ClamAV scanning on Cloud Run with a quarantine bucket and Cloud Tasks asynchronous
processing.
• Developed Node.js APIs (initially Express, later migrated to NestJS) deployed as Cloud Run services and Cloud

Functions, with Pub/Sub and Cloud Tasks for asynchronous workloads, Stripe for billing, Dockerized services and
GitHub Actions CI/CD.
• Contributed to a Node.js/TypeScript service, backed by PostgreSQL, that ingests and serves Meta (Facebook) Marketing

API ad data for the VisCap apps.
• Integrated several LLM-based features into product workflows, each used thousands of times a month: text and image

generation and analysis of text and media content, with structured input/output schemas and prompt design for
consistent, reliable output.
• Covered features with unit, component and end-to-end tests (Jest, React Testing Library, Cypress), and introduced a

team-wide “QA Guide” practice that shortened the developer QA cycle.
• Improved load speed of several data-heavy pages, including large tables and media galleries, by more than 2x through

code splitting and lazy loading.
• Optimized rendering performance of data-heavy features (complex forms, tables, drag-and-drop, interactive charts and

data-visualization tools, real-time Firestore listeners).
• Served on the production support rotation for about two years, starting in the first month, diagnosing hundreds of

user-reported issues using LogRocket session replays, GCP logging and direct communication with users.
Contract, workplace-management software company Jan. 2024 – Mar. 2024
Full-Stack Developer (React Native, MERN) Remote
• Contributed to the development, maintenance and bug fixing of an internal cross-platform (iOS/Android) task-tracking

and issue-reporting app, used by several hundred employees.
• Worked on its MERN stack: a React Native client with a Node.js/Express API and MongoDB.

ITCraft Oct. 2020 – Dec. 2023
Full-Stack Developer Remote
• Worked across the full stack on 5+ client projects in a staff-augmentation model, in Scrum teams.

• Created admin and analytics interfaces for online businesses: client-database management, complex data-presentation

and reporting features, and user-behavior analytics for thousands of users.
• Implemented responsive, component-driven interfaces with React, Next.js and TypeScript, using Redux and Zustand for

state management, Formik for forms, and Material UI and Bootstrap for design systems.
• Wrote unit and component tests in Jest and React Testing Library.

• Built the back ends behind those interfaces on MERN and PERN stacks (Node.js/Express REST APIs with MongoDB,
or PostgreSQL with Prisma) and on Firebase, designing their data models and endpoints.
• Maintained and extended legacy front ends written in JavaScript and jQuery, incrementally migrating parts of them to

React.
Technical Skills
Languages: TypeScript, JavaScript (ES6+), SQL, HTML5, CSS3/SCSS (Sass)
Front End: React (React.js), Next.js; React Native, Expo, Electron; Redux, Redux Toolkit (RTK), Zustand, TanStack
Query (React Query), TanStack Table; react-hook-form, Formik, Yup; Ant Design (antd), Material UI (MUI), shadcn/ui,
Radix UI, Bootstrap, Tailwind CSS; ECharts (Apache ECharts), D3 (D3.js), React Native Skia; Webflow
Back End: Node.js, Express (Express.js), NestJS (Nest.js); REST APIs, WebSockets / real-time (Ably); Mongoose, Prisma
(ORM); Zod, Joi; Better Auth; Stripe; Firebase Cloud Functions
Cloud & Infrastructure: Google Cloud Platform (GCP), Cloud Run, Cloud Functions, Cloud Tasks, Pub/Sub, Secret
Manager, Vertex AI; Amazon Web Services (AWS), AWS Lambda, Amazon CloudFront, Amazon S3, Amazon SNS, AWS
CDK; Firebase, Vercel, Cloudflare; Docker, GitHub Actions (CI/CD)
Data & Search: PostgreSQL (Postgres, Neon); MongoDB (Mongo, Atlas), Firestore; Redis (Upstash); Typesense
Testing: Jest, Vitest, React Testing Library (RTL), Supertest; Cypress, Playwright
Methodologies: Agile (Scrum, Kanban)
AI / LLM: LLM API integration, structured outputs, prompt design (prompt engineering)
AI-Assisted Development: Claude Code, agentic coding workflows, custom agent skills, MCP integrations, AI-assisted
design and implementation, AI-assisted testing and documentation
Tooling: Git, pnpm, Turborepo (monorepo); ESLint, Prettier, Knip; Figma, Mermaid; LogRocket
Personal Projects
AdLens | AI analysis for video ads useadlens.com | github.com/haggifer/adlens
Likely Weather | Multi-model weather forecast likelyweather.com | github.com/haggifer/likelyweather
firestore-iterator | Concurrent Firestore iteration (npm package) github.com/haggifer/firestore-iterator
Education
National Technical University “Kharkiv Polytechnic Institute” 2017 – 2021
Bachelor’s Degree, Chemical Engineering Kharkiv, Ukraine
Languages
English — C1 (working proficiency, 4+ years in English-speaking teams; EFSET certificate: cert.efset.org/en/hC8UAu) ·
Ukrainian — C2 (Proficient) · Russian — Native