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Konstantin Merenkov

Senior Software Engineer

Payments, Kotlin Multiplatform on Android and iOS

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Sydney, AustraliaFull Australian work rights

Software engineer since 2021, mostly where money moves. At Maytes I am one of two engineers shipping a consumer payments product: Android and iOS share one Kotlin Multiplatform codebase, and the web app is React. I also build and run my own product, Suby, on the App Store and Google Play, and maintain the Kimplify open source libraries for money on Kotlin Multiplatform. Master's in AI and Big Data.

Experience

  1. Maytes Maytes

    – Present

    Sydney, Australia

    Maytes (formerly KttiPay) Senior Android Engineer

    Scope: Android, iOS and web

    Now shipping split-at-checkout payments.

    A consumer payments product. Two engineers ship all three platforms; the web app is React.

    • Moved a legacy Java Android app to Kotlin Multiplatform and Compose Multiplatform in increments, without a big-bang rewrite.
    • Brought the iOS app onto the same code, so both native apps ran fully on one shared codebase about three months after I joined.
    • Wrote KPayment, which puts Apple Pay and Google Pay behind one Kotlin API on iOS, Android and the web. Maytes released it as open source.
    • Built StandupBot: Claude drafts updates from Linear tickets and GitHub pull requests, each person approves, edits or skips, and the app posts to Slack on a schedule.
    • Kotlin Multiplatform
    • Compose Multiplatform
    • Apple Pay
    • Google Pay
    • React
    • Claude
    Read the Maytes case study

  2. –

    GameForest Android Engineer

    • Delivered Smart Food, a food delivery app for customers, and Courier UP, its companion app for couriers, with live location.
    • Built the app for the Gus-Karas restaurant chain with Material 3.
    • Google Maps SDK
    • Foreground services
    • WorkManager
    • Notifications
    • DataStore
    • Room
    • Jetpack Compose
    • Custom views
    • Multi-module MVVM
    • Coroutines

  3. –

    Freelance and contract

    • ePlatform Digital Libraries Wheelers ePlatform Limited, via Upwork, 2023 – 2024

      Built the app for school and public library eBooks and audiobooks. Raised the crash-free user rate from 96% to 99.8%. Built a more efficient audio player on Jetpack Media3, added Room tables for user profiles, and refined the book-expiry notifications.

    • SLEKE. With Sierra Nevada Digital, 2026

      Apps for SLEKE.'s distraction-free phone on OdysseyOS, in Kotlin with AOSP and GrapheneOS integration. Its Enough Phone is on Kickstarter.

      • SLEKE. Migrate for Android and iOS (App Store), plus its landing page migrate.sleke.io: contacts, photos, videos and files move phone to phone over Wi-Fi, with no account and no cloud copy.
      • The Launcher, the OdysseyOS home screen, for Google Play and as a system app; the setup wizard; the SLEKE. Store.
      • All built on SLEKE.'s custom neumorphic design system: Kotlin Multiplatform foundations and components shared across the apps.

    • On-Pin 2023 – 2024, Sydney

      Built PopMeter, a tablet app that tracks live group progress on a golf course, with Jetpack Compose, Flow and Retrofit. Moved the VPGS in-cart app from Java to Kotlin and added GPS tracking with support for both Android 4 and Android 10 devices. Added Crashlytics and ProGuard.

    • AutoRedemption Contract work

      Built an Android app for auto dealers that runs reliably in the background and sends SMS automatically from a chosen SIM card, over a GraphQL API.

    • Simple Mobile Apps Open source

      Contributed to the phone, SMS, file manager, gallery and launcher apps. Replaced Java threads with Kotlin coroutines.

Projects

All projects

Suby

subyapp.com

Subscription tracker for iPhone and Android. Live on the App Store and Google Play. Built and run solo.

  • One Kotlin Multiplatform and Compose Multiplatform codebase for both apps: reminders before each renewal, shared plans, 94 currencies, a calendar and home-screen widgets.
  • Built the backend in Kotlin with Ktor and Postgres, deployed on Fly.io: cloud backup with versioned snapshots, retry-safe uploads and per-user locking.
  • Built an import that reads a screenshot or a bank statement with Claude Haiku. The model must answer through a fixed schema, results stream to the phone, and every item goes through a review screen before it is saved.
  • Kotlin Multiplatform
  • Compose Multiplatform
  • Ktor
  • Postgres
  • Fly.io
  • Claude Haiku

Education

  • –

    Master's, AI and Big Data

    Far Eastern Federal University

    Thesis: Android biofeedback using wearable measurements and a machine-learning model to predict stress.

    github.com/Merkost/Biofeedback

  • –

    Bachelor's, Information Systems and Technologies

    Far Eastern Federal University

  • –

    Diploma of Project Management

    Australian College of Business Intelligence, Sydney

Skills

Languages
Kotlin, Swift, Java, Python, SQL
Mobile and web
Kotlin Multiplatform, Compose Multiplatform, Jetpack Compose, Android SDK, SwiftUI, Kotlin/JS
Payments
Apple Pay, Google Pay, decimal money arithmetic, multi-currency
Backend
Ktor, PostgreSQL, Supabase, Fly.io
AI
LLM APIs with structured output and streaming, stress prediction from wearable data, prompt-injection guards, coding agents in daily use
Practices
Coroutines and Flow, Room, Koin, MVVM and MVI, crash monitoring

Writing

ProAndroidDev
  1. MoneyFloating point can't hold a cent. BigDecimal can, until commonMain
  2. PaymentsKPayment: Apple Pay and Google Pay for Kotlin Multiplatform
  3. ComposeType-safe bottom navigation in Jetpack Compose
  4. ComposeA Spotify-inspired buffering slider in Jetpack Compose
  5. Android, Foreground services in Android 14: what's changing

Languages

English
Fluent
Russian
Native

Download PDFUpdated

  • Introsection
  • Worksection
  • Open sourcesection
  • Tools and experimentssection
  • Aboutsection
  • Writingsection
  • Activitysection
  • Shipping logsection
  • Nowsection
  • Contactsection
  • Maytes case studypage
  • Suby case studypage
  • Metronomeproject
  • Roomproject
  • Honqproject
  • op-botproject
  • StandupBotproject
  • SLEKE.project
  • ePlatform Digital Librariesproject
  • Wallaby VPNproject
  • Kimplifyproject
  • KPaymentproject
  • Lingvoproject
  • PopMeterproject
  • AutoRedemptionproject
  • Mercuryproject
  • Smart Foodproject
  • Fishing Notesproject
  • Gus-Karasproject
  • Biofeedbackproject
  • One Playground app conceptproject
  • Barloproject
  • RoadConditionsproject
  • Scheduleproject
  • Lumiproject
  • KMPaceproject
  • FreeDroidproject
  • Android Drawable Previewproject
  • Nowpage
  • Usespage
  • Notespage
  • Résumépage
  • Email Konstantincontact
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  • GitHublink
  • LinkedInlink
  • subyapp.comlink

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