Product build from zero
Shape the scope, design the architecture, build the core product, and prepare a realistic launch path.
Independent product engineer
Independent mobile & desktop app contractor for Android and Kotlin Multiplatform.
Apps that ship — not just start.
I'm Andrii Cherniakhov. I take mobile, desktop, and backend products from first scope to store release — Android, Kotlin Multiplatform, iOS, and more — then stay on to maintain them.
Currently booking new projects · replies within 1 business day
Architecture before momentumNative quality where users feel itShared code only where it earns its keepClear release ownership
Engagements
Senior Android and Kotlin Multiplatform app developer for launch-critical work.
The work is scoped around outcomes, not vague hours: reliable architecture, production code, clean releases, and a product that can keep moving after version one.
Senior implementation support
Join an existing team to unblock mobile, desktop, backend, or cross-platform delivery without adding process drag.
Technical rescue and rebuilds
Stabilize codebases that have outgrown their first version: data flow, releases, UI quality, testing, and maintainability.
Selected work
Products designed, built, and shipped to real users.
A few apps taken from first idea to store release — across mobile and desktop.
Koru
iOS · AndroidBudget & expenses, together as a family
A family budgeting app for households to track shared spending in real time and reach money goals together.
Design, build & release
Scruto
macOSFootage, tagged and searchable — automatically
A desktop app that auto-tags, transcribes, and renames video and photo files so editors can find footage fast.
Design, build & release
iCoach
iOSClient & workout manager for personal trainers
A private, on-device app for trainers to log workouts, schedule sessions, and track client progress — no sign-up.
Design, build & release
Client feedback
What clients say after shipping.
Verified 5-star reviews from Upwork clients — backed by a Top Rated Plus badge and a 100% job-success record.
“Andrii is not only a wonderful person to work with but also an exceptionally skilled programmer. He approaches his work with great efficiency and delivers excellent results.”
“Andrii is straightforward to work with; he has shown professionalism from day one and was easily able to understand the tasks before him.”
“Andrii is a pleasure to work with. He is knowledgeable, fast and professional.”
“Skilled developer who helped my Android app go to the next level. Will hire again for sure!”
“Great Android developer, would love to work with again.”
“Andrii is a very high skilled Android developer, I would definitely work with him again.”
Process
A direct path from first scope to production maintenance.
The workflow stays boring on purpose: define the target, make the technical decisions early, ship in visible increments, and keep the release path clean.
- 01
Scope
Turn a rough idea into a costed plan — features, milestones, and a realistic timeline.
- 02
Architect
Design a structure that stays maintainable as the product and the team grow.
- 03
Build
Ship production code — native Android, Kotlin Multiplatform, and Compose Multiplatform.
- 04
Ship
Release to the App Store and Google Play with analytics and crash reporting in place.
- 05
Maintain
Stay on after launch for fixes, OS updates, and the next round of features.
Stack & capabilities
Native-first engineering, with shared code where it genuinely reduces cost.
The practical pieces needed to build, integrate, release, and improve — grounded in real shipped work.
Mobile & desktop
- Android · Jetpack Compose
- Kotlin Multiplatform
- Compose Multiplatform
- iOS · SwiftUI
Backend & data
- Ktor services
- Supabase · Postgres
- Firebase
- SQLDelight & Room
- Node · Express
Product & integrations
- RevenueCat subscriptions
- MapLibre maps
- OpenAI features
- Koin & Coroutines
Web
- Next.js
- React
- Tailwind CSS
- Payload CMS
FAQ
The practical questions before we start.
- How do you charge?
- Most work runs hourly or as a fixed price per milestone, with retainers for ongoing maintenance. Tell me what you are building and I will recommend the structure that fits.
- Which timezone do you work in?
- I am based in the EU (Poland) and keep solid daily overlap with European and US-East teams. Clear async updates keep work moving outside shared hours.
- Are you solo? Can you handle a full build?
- I work independently and take products end to end, staying the single point of ownership. For larger scopes I bring in trusted specialists without adding process drag.
- How does billing and invoicing work?
- I issue compliant Polish VAT invoices that are straightforward for EU companies to expense, and I can work with your contract, NDA, and IP-assignment terms.
- How do we start?
- Email a short note: where the product is now, what the next release needs, and which platforms matter. I reply within one business day with the most useful next step.
Next step
Send the short version of what you need to ship.
Include where the product is now, what needs to be true in the next release, and which platforms matter. I will respond with the most useful next move.
Currently booking new projects · replies within 1 business day