Romain Boisselle

CATS develops the mobile banking app deployed in all 39 Crédit Agricole Regional Banks.

When I joined, an initial KMP foundation existed but had structural weaknesses — non-standard iOS integration, inconsistent dependency injection management, tight coupling between functional flows.

▸ Architecture

Stabilized foundations, redesigned DI, conceived a KMP navigation library allowing flows to invoke each other without knowing each other — the host app manages routing, data is passed via serialization between independent modules.

▸ Cross-functional CI/CD

Built the delivery pipeline for the entire organization — shared scripts covering build, tests, QA and production deployment of KMP modules, Compose/Swift/CMP flows, and integration with host apps. Each new project only requires a few lines of GitLab CI configuration.

▸ Enablement

Supported ~30 Android/iOS developers across squads — workshops, training, pair programming, group code reviews, 1:1s based on profiles. Architecture documentation, KMP guidelines, and flow creation templates.

→ Result: from 1 KMP module to 20 in production. 80-90% shared code between Android and iOS. Squads create and deliver new modules with complete autonomy.

Stack: Kotlin Multiplatform · Jetpack Compose · SwiftUI · Compose Multiplatform · Clean Architecture · Redux/MVI · Cross-platform Navigation · Kodein-DI · Coroutines · Ktor · GitLab CI · Kotlin Serialization

Scenario is an AI platform for image generation for video game studios, funded at $10M+.

▸ Phase 1 — Android App Launch

Android app delivered to production in less than a month, from scratch — MVI architecture, Jetpack Compose, complete CI/CD pipeline, Auth0 authentication. Inspired by the existing iOS app in SwiftUI, which I also maintained. From this phase, the architecture was designed for future KMP sharing.

▸ Phase 2 — New Compose Multiplatform App

Launched a second app in a new market using Compose Multiplatform, reusing the architectural foundation prepared from Phase 1. Integrated in-app purchases (App Store + Google Play), Firebase Realtime Database, anonymous authentication.

The mobile team went from 2 specialized developers (1 iOS + 1 Android) to 1 developer capable of delivering on all platforms.

→ Result: two apps in production, a shared foundation, and halved time-to-market thanks to KMP anticipation from day 1. The necessary mobile headcount was reduced by half.

Stack: Compose Multiplatform · Kotlin Multiplatform · Jetpack Compose · SwiftUI · MVI · Auth0 · Firebase Realtime Database · In-App Purchases (StoreKit / Google Play Billing) · GitHub Actions · Firebase App Distribution

Mealz develops an SDK integrated into retailers' grocery apps — it offers recipes and automatically generates a shopping list.

The challenge: evaluate and stabilize the Kotlin Multiplatform SDK architecture before its release on Android and iOS.

▸ 2-Week Audit

Complete architecture analysis, identification of technical risks, recommendations report — KMP best practices, coroutines, Swift interoperability. Recommendations on KMP strategy: what to share between platforms, what to keep native.

→ Result: recommendations implemented by the Mealz team autonomously, without further support. Enhanced testability, improved performance, stabilized architecture.

Stack: Kotlin Multiplatform · SDK Architecture · Coroutines · Kotlin/Swift Interoperability · Testing · Architecture Documentation