Kotlin Multiplatform Instagram Clone

A reference Kotlin Multiplatform (KMP) project recreating an Instagram-style application across:

• Android
• iOS
• Desktop (JVM)
• Web (JS + Wasm)
• Ktor Server Backend

It showcases vertical, feature-first modularization with strict Clean Architecture, shared logic, typed navigation, Composable UI, Ktor networking, SQLDelight storage, and fully isolated feature slices.

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📁 Folder Structure

composeApp/
  androidMain/
  iosMain/
  commonMain/
  jvmMain/
  webMain/

core/
  UI/
  Navigation/
  Network/
  Cache/

feature/
  Auth/
  Feed/
  Explore/
  NewPost/
  Likes/
  Profile/

shared/

server/

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📦 Dependency Graph

graph TD
    composeApp --> core:UI
    composeApp --> core:Navigation
    composeApp --> core:Network
    composeApp --> core:Cache
    composeApp --> shared
    composeApp --> feature:Auth
    composeApp --> feature:Feed
    composeApp --> feature:Explore
    composeApp --> feature:NewPost
    composeApp --> feature:Likes
    composeApp --> feature:Profile

    feature:Feed --> core:UI
    feature:Feed --> core:Navigation
    feature:Feed --> core:Network
    feature:Feed --> core:Cache

    feature:Auth --> core:Navigation
    feature:Auth --> core:UI

    feature:Explore --> core:UI
    feature:Explore --> core:Navigation

    feature:NewPost --> core:UI
    feature:NewPost --> core:Navigation

    feature:Likes --> core:UI
    feature:Likes --> core:Navigation

    feature:Profile --> core:UI
    feature:Profile --> core:Navigation

    shared --> PlatformUtils[(platform utils)]
    server --> shared

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🧭 Navigation Flow

graph LR
    AuthRoute --> FeedRoute
    FeedRoute --> ExploreRoute
    FeedRoute --> NewPostRoute
    FeedRoute --> LikesRoute
    FeedRoute --> ProfileRoute

    ExploreRoute --> FeedRoute
    LikesRoute --> FeedRoute
    NewPostRoute --> FeedRoute
    ProfileRoute --> FeedRoute

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🔧 Gradle Dependency Flow

graph TD
    composeApp["composeApp:commonMain"] -->|api| shared
    composeApp -->|api| feature:Auth
    composeApp -->|api| feature:Feed
    composeApp -->|api| feature:Explore
    composeApp -->|api| feature:NewPost
    composeApp -->|api| feature:Likes
    composeApp -->|api| feature:Profile

    composeApp -->|api| core:UI
    composeApp -->|api| core:Navigation
    composeApp -->|api| core:Network
    composeApp -->|api| core:Cache

    feature:Feed -->|api/impl| core:Navigation
    feature:Feed -->|impl| core:UI
    feature:Feed -->|api| core:Network
    feature:Feed -->|api| core:Cache

    server -->|implementation| shared

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🏗 Architecture Overview

The architecture follows Clean Architecture, multiplatform modularization, and feature isolation, allowing each layer to scale independently.

📱 composeApp/

The cross-platform entry point containing:

• Root App() composable
• Koin bootstrap
• App theme
• Navigation host
• Top & bottom bars
• Typed route registry

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🧩 core/

Shared foundation modules:

core:UI

• Theme + color system
• AppScaffold
• TopAppBar, BottomNavigation
• UI config provider

core:Navigation

• Typed route system using @Serializable
• FeatureEntry registration
• Centralized NavHost wiring

core:Network

• Ktor HttpClient wrapper
• Retry, timeouts, JSON, base-URL config
• Safe Result<T> helpers: getSafe, postSafe, etc.

core:Cache

• SQLDelight setup
• Multiplatform drivers (Android/iOS/JS/JVM)

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🔁 shared/

Pure KMP utilities shared everywhere:

• Expect/actual platform APIs
• Coroutine dispatchers
• Logging utils
• Constants & configuration

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🧱 feature/

True vertical slices containing:

• UI (Compose)
• State (ViewModel + events + reducers)
• Domain (models + repositories)
• Data (remote + cache + mappers)
• Navigation entry (FeatureEntry)
• DI module

Features included: Auth, Feed, Explore, NewPost, Likes, Profile.

Each feature depends on core, but never on other features.

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🌐 server/

A lightweight Ktor backend:

• Reuses shared data models
• Exposes REST APIs
• Demonstrates full multiplatform sharing (e.g., constants, DTOs)

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🧩 DI Bootstrap Example

fun initKoin(appDeclaration: KoinAppDeclaration = {}) {
    startKoin {
        appDeclaration()
        modules(
            sharedModule,
            networkModule,
            cacheModule,
            authModule,
            feedModule,
            exploreModule,
            newPostModule,
            likesModule,
            profileModule
        )
    }
}

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🚀 Getting Started

Android

./gradlew :composeApp:assembleDebug

Desktop (JVM)

./gradlew :composeApp:run

Web (JS)

./gradlew :composeApp:jsBrowserDevelopmentRun

Web (Wasm)

./gradlew :composeApp:wasmJsBrowserDevelopmentRun

iOS

Open in Xcode or run from IntelliJ.

Server

./gradlew :server:run

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📄 License

MIT License — see LICENSE.