Kotlin Multiplatform Compose Multiplatform Ktor Course Challenge

Chirp Messaging Client

A synchronized, real-time messaging application targeting Android, iOS, and Desktop with 100% shared business logic.

Chirp Messaging Client Mockup

The Overview

Chirp is a complete enterprise-grade messaging solution designed to showcase modern cross-platform development. Built entirely in Kotlin, it uses Kotlin Multiplatform (KMP) for shared state management and Compose Multiplatform (CMP) for unified UI rendering across mobile and desktop platforms.

The Challenge

Developing a messaging application requires handling highly asynchronous data flows, managing unstable network connections, and ensuring a smooth user pipeline across distinct operating systems.

The main engineering challenge was to share as much code as possible without compromising on native performance. This meant standardizing WebSockets, local SQLite persistence (Offline-first), and UI components from a single codebase while respecting platform-specific APIs for notifications and file systems.

Architecture & Technical Decisions

To overcome these challenges, Chirp was built on a Multi-Module Clean Architecture foundation. The application enforces a strict Unidirectional Data Flow (UDF), pushing state downwards and propagating events upwards.

Structural Breakdown

  • Feature Encapsulation: Modules are split into strict layers (e.g., feature:auth, feature:chat), isolating domain business logic from the UI layer.
  • Offline-First Synchronization: A reliable implementation using Room/SQLite bundles ensures messages are cached locally, allowing full app usage and background queueing during network dropouts.
  • Real-Time Duplexing: Ktor Client powers the networking layer, managing smooth REST calls and WebSocket streams for instant message delivery without polling overhead.
  • Dependency Injection: Built using Koin to securely provide multiplatform dependencies natively to Android, iOS, and desktop targets.

Platform Consistency

To ensure pixel-perfect fidelity and smooth animations, I utilized Compose Multiplatform (CMP). The dynamic typography and RTL support (Arabic/English) are gracefully handled using centralized expect/actual bindings connected to a core design system module.

Impact & Results

  • 100% Code Sharing achieved for business logic across Android, iOS, and Desktop platforms using KMP.
  • Zero-polling communication integrated via WebSockets, reducing backend payload and latency.
  • Excellent offline capabilities enabling continuous data interaction and background sync queued implicitly upon reconnection.

The Tech Stack

Language Kotlin 2.2
Architecture Clean MVI
Networking Ktor WebSockets
UI Framework Compose MP
Persistence Room DB
DI Framework Koin
Push Delivery Firebase Cloud
Async Coroutines/Flow