About
Engineer and founder
I'm Sviat, a Tech Lead and technical co-founder based in Warsaw, Poland. I have spent 6+ years in startups and product development as a fullstack engineer: mobile apps, web, desktop and backend. Most of my projects started from an empty repo — I chose the architecture and took them all the way to release on the App Store and Google Play. MVPs are my strongest side.
That is more than 20 products in very different fields: fitness and health, medical documents encrypted on the device, a desktop ground control station for drone operators, social platforms with creators, live video and payouts, education platforms, an HR system, a crypto exchange, e-commerce for a pharmacy chain and AI products.
Building teams, not just code
As a founder, I took on client projects, including from Upwork, put together the team for each one and answered to the client for the result. We delivered an online fitness platform in 8 months with a team of 5, and a farm discovery app in 5 months with a team of 4. That is where I learned to think in products and outcomes, not tasks.
What I work on now
Three client products at once: Mobile Lead on a pharmacy e-commerce app, Senior Fullstack on an AI platform for families, and Senior Mobile at a Ukrainian startup. Alongside them I build my own products, Gymni and Electron Publish Pro. There I own not only the code but the marketing too — positioning, the funnel, content and the first users — so a product does not stall between “built” and “sold”.
How I can help
Build a product from scratch, pull a stuck project back on track, or look at it from the outside — from the technical side and from the side of “why people don't get to the purchase”.
Technologies I have shipped with
Taken from the code of the products I have worked on, grouped by area, with the cases that show them in practice.
Mobile
- React Native
- Expo
- EAS Build
- Expo Router
- React Navigation
- TypeScript
- Native modules in Kotlin
- Native modules in Objective-C++
- Ionic
- Reanimated
- Gesture Handler
- Skia
- Victory Native
- Rive
- Lottie
- FlashList
- NativeWind
- React Native Paper
- VisionCamera
- react-native-maps
- Google Places
- Bottom Sheet
- i18next
In practice: Medical documents with on-device encryption · Video calls built from scratch for a fitness platform · An MVP in one month that won the next contract · Gymni: an app and platform for personal trainers · Live sports debates app with real-time audio and video
State, data and forms
- Redux Toolkit
- redux-persist
- TanStack Query
- Offline query persistence
- Zustand
- MobX
- RTK Query
- Realm
- MMKV
- Immer
- Apollo Client
- GraphQL
- GraphQL Codegen
- OpenAPI codegen
- Axios
- react-hook-form
- Formik
- zod
- Yup
In practice: No-code app builder ready for Web Summit
Desktop
- Electron
- electron-builder
- electron-updater
- electron-store
- @electron/notarize
- @electron/osx-sign
- macOS hardened runtime
- Windows and Microsoft Store builds
- serialport
- MAVLink
- Leaflet maps
- ffmpeg
- HLS / DASH / RTSP video
- IndexedDB offline storage
- pdf.js
In practice: Hiring time cut by 40%
Web
- React
- Next.js
- Vite
- Webpack
- Rollup
- Tailwind CSS
- shadcn/ui
- Radix UI
- MUI
- Mantine
- Sass
- BEM
- Bootstrap
- Materialize
- Moon Design System
- Vue 3
- Gulp
- Storybook
- Recharts
- CKEditor 5
- Three.js
- Framer Motion
In practice: No-code app builder ready for Web Summit
Backend
- Supabase Postgres
- Supabase Edge Functions
- Supabase Realtime
- Supabase Auth
- Firebase Cloud Functions
- Firestore
- Firebase Auth
- NestJS
- NestJS microservices
- Express
- Fastify
- Ruby on Rails
- Sidekiq
- Strapi
- PostgreSQL
- MongoDB
- Firebase Realtime Database
- Prisma
- Sequelize
- Drizzle ORM
- Redis
- Swagger / OpenAPI
- Docker
In practice: Gymni: an app and platform for personal trainers · Live sports debates app with real-time audio and video
Real-time and media
- mediasoup
- WebRTC
- protoo
- Agora
- Agora cloud recording
- LiveKit
- Stream Chat
- Pusher
- Socket.IO
- WebSocket
- hls.js
- ffmpeg
- react-native-video
In practice: Video calls built from scratch for a fitness platform · Live sports debates app with real-time audio and video
AI
- OpenAI / ChatGPT
- Anthropic Claude
- Perplexity API
- Vercel AI SDK
- LangChain
- AI document parsing
In practice: An MVP in one month that won the next contract
Payments, identity and security
- Stripe
- RevenueCat
- Adapty
- Fondy
- TrueLayer open banking
- Mamopay
- Paddle
- Onfido KYC
- Privy wallet
- Passkeys
- AWS Cognito
- Google and Apple sign-in
- Auth.js
- Firebase Authentication
- Microsoft Graph / MSAL
- AES-256 and RSA
- crypto-js
- SSL pinning
- Encrypted storage
In practice: Medical documents with on-device encryption · Video calls built from scratch for a fitness platform · Gymni: an app and platform for personal trainers
Growth and observability
- Firebase Analytics
- Crashlytics
- Remote Config
- Sentry
- AppsFlyer
- OneSignal
- Notifee
- Firebase Cloud Messaging
- GA4
In practice: Gymni: an app and platform for personal trainers
Quality and releases
- Fastlane
- GitHub Actions
- GitLab CI
- CircleCI
- Over-the-air updates
- Jest
- Testing Library
- Cypress
- Playwright
- Vitest
- React Testing Library
- SonarQube
- Docker
- Husky + commitlint
- App Store
- Google Play
- Vercel
In practice: An MVP in one month that won the next contract
Experience
Now
Mobile Lead
Pharmacy e-commerce chain
Lead the iOS and Android apps on top of Magento and GraphQL: checkout, pharmacy map, loyalty cards, releases to both stores.
Now
Senior Fullstack
AI platform for families
Now
Senior Mobile
Ukrainian consumer app startup
Now
Founder
Gymni · Electron Publish Pro
Build my own products end to end, from the code to positioning, the funnel and the first users.
Founder
Product team for client projects
Took on client projects, including from Upwork, put together the team for each one and answered to the client for the result. Delivered an online fitness platform in 8 months with a team of 5, and a farm discovery app in 5 months with a team of 4.
Jun 2025 –
React Native Developer
HealthTech company
Built a medical documents app from scratch with on-device PDF encryption in native modules; published on the App Store and Google Play.
Jul 2022 – Jun 2025
React / React Native Developer
Product company
Fitness app with in-house video calls (MVP in 2 months, won a new project), a ChatGPT education app (MVP in 1 month, deploy time −50%), and a no-code app builder (alpha for Web Summit in 2 months, 500 active users).
2022
Electron Developer
HR system
Desktop HR system with a Trello-style hiring board; time-to-hire −40%; signed macOS release.
Mar 2021 – Jul 2022
React Developer
Crypto exchange
Frontend architecture and UI kit; MVP shown to the client in 2 months, securing a new project.
- Education
- Bachelor in Computer Engineering, King Danylo University (2022–2025)
- Languages
- Ukrainian (native), English (upper-intermediate)
Have a similar problem? Tell me about it.
A few sentences about the business problem are enough to start.