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Kotlin Multiplatform App · Android & iOS · 2026

TakaKoi: Personal Finance & Budget Tracker

A local-first Android and iOS finance app for expenses, budgets, savings goals, loans, and recurring income, with one shared Kotlin codebase and no runtime network calls.

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[ EVD ]

Engineering evidence

My contribution
Solo · Product, architecture, shared UI, persistence, and CI
Outcome
Open source (Apache 2.0) with CI artifacts; store release not yet configured
Decision record 01
Chose local-first storage with no network layer, because a finance app earns trust by never needing to send the data anywhere.
[ IMG ]

Screenshots · 4 captures

TakaKoi: Personal Finance & Budget Tracker screenshot 101 / 04
[ ARC ]

Architecture

  1. 01

    Shared UI

    • Compose Multiplatform
    • Material 3, theme presets

  2. 02

    State

    • MVVM, StateFlow
    • Kotlin coroutines

  3. 03

    Local data

    • Room KMP + bundled SQLite
    • Excluded from device backups

  4. 04

    Delivery

    • GitHub Actions per branch
    • Debug APK + iOS framework
[ KEY ]

Technical highlights

  1. 01

    Shared UI and persistence across Android and iOS with Kotlin Multiplatform and Room KMP.

  2. 02

    Drew a strict privacy boundary: no account, analytics, telemetry, cloud sync, or network calls, and the finance database is excluded from backups.

[ STK ]

Stack

  • Kotlin Multiplatform
  • Compose Multiplatform
  • Room KMP
  • SQLite
  • Coroutines
  • GitHub Actions