Echo

A mobile flashcards app that fuses Duolingo TinyCards' playfulness, Anki's spaced-repetition, and Pubky's decentralized identity and social graph. iOS + Android, built with Kotlin Multiplatform.

• Product spec: docs/specs.md — Paste-to-Import, the primary v1 flow.
• Design brief: design/DESIGN_GUIDELINE.md — screens, components, design system.
• Architecture: docs/Architecture.md — module layout, layering, state flow, open questions.

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Architecture at a glance

Echo is a Kotlin Multiplatform project with shared business logic and native UIs per platform:

• shared/ — KMP module holding domain models, repositories (which own the business logic), and ViewModels. Platform glue (Pubky FFI, TTS, haptics) via expect/actual.
• composeApp/ — Android app. Jetpack Compose screens, Jetpack Navigation, Koin DI.
• iosApp/ — iOS app. SwiftUI screens, NavigationStack, Koin bootstrap.

Identity, tags, follows, and published decks are backed by Pubky via pubky-core-ffi-fork (binding mechanism — UniFFI vs handwritten expect/actual — still TBD; see Architecture §7).

Module layout

echo/
├── shared/
│   └── src/
│       ├── commonMain/kotlin/com/github/jvsena42/eco/
│       │   ├── domain/        # models (pure Kotlin)
│       │   ├── data/          # repositories (own business logic) + PubkyClient
│       │   └── presentation/  # ViewModels (StateFlow-based)
│       ├── androidMain/       # actuals: Pubky FFI, TTS, haptics
│       └── iosMain/           # actuals: Pubky FFI, TTS, haptics
│
├── composeApp/src/androidMain/kotlin/com/github/jvsena42/eco/
│   ├── ui/                    # Compose screens + navigation
│   ├── di/                    # Koin Android module
│   └── MainActivity.kt
│
└── iosApp/iosApp/
    ├── Views/                 # SwiftUI screens
    ├── Navigation/            # NavigationStack
    ├── DI/                    # Koin bootstrap
    └── iOSApp.swift

Stack

Concern	Choice
UI (Android)	Jetpack Compose + Material 3
UI (iOS)	SwiftUI + NavigationStack
Shared logic	Kotlin Multiplatform (commonMain)
DI	Koin
Async	Coroutines + Flow (Swift bridge: SKIE, TBD)
Local storage	SQLDelight + multiplatform-settings
Identity / social	Pubky (pubky-core-ffi-fork)
Navigation	Per-platform native

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Build and run

Android

./gradlew :composeApp:assembleDebug

Or use the run configuration from your IDE's toolbar.

iOS

Open /iosApp in Xcode and run, or use the run widget in your IDE.

Tests

./gradlew :shared:allTests

Unit tests for parsers, repositories, and ViewModels live in shared/src/commonTest.

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Project status

v1 is in early scaffolding. The current skeleton establishes package boundaries and interfaces per docs/Architecture.md; concrete implementations (SQLDelight schema, Pubky FFI wiring, first ViewModels) are the next step.

See docs/Architecture.md §12 for open questions that block feature work.

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Learn more about Kotlin Multiplatform.