Kotlin Multiplatform Lead & Partner
Matthias Ernst
I help companies ship Android, iOS, desktop, and web apps from one Kotlin codebase, so the business logic is written and tested once.
About
Grüezi. I'm Matthias, a senior software engineer focused on Kotlin Multiplatform. I build shared codebases that run on Android, iOS, desktop, and web, so teams write their logic once instead of maintaining two or three copies of it.
Over the last 7+ years I've built software for banking, insurance, and automotive clients: the frankly 3a pension app at Zürcher Kantonalbank, the Helsana+ health insurance app, and a connected-vehicle SDK for the Toyota Group.
I also co-founded Ernst & Conte GmbH, a Swiss consultancy for KMP and app development. If you're weighing Kotlin Multiplatform for your product, or need someone who has shipped it in production, get in touch.
Technical Skills
What I work with, and how well I know it.
Kotlin & KMP Expert
My daily driver: shared module architecture, Kotlin/Native interop, coroutines and Flow, and multi-module Gradle builds.
Compose Multiplatform Expert
Shared declarative UI on Android, iOS, desktop, and web, for products where one interface codebase makes sense.
Android & Jetpack Compose Expert
Native Android in production since 2019, from UI and architecture to Play Store release pipelines.
iOS & Swift Proficient
Swift on the iOS side of KMP projects, including framework packaging, interop, and the code where shared Kotlin meets the native app.
KMP Libraries & Tooling
- Ktor
- SQLDelight
- Koin
- kotlinx.serialization
- Coroutines & Flow
- Kotlin/Native
- Gradle (multi-module)
- SKIE
- React Native interop
DevOps & Infrastructure
- Kubernetes
- Helm
- Docker
- GitHub Actions
- GitLab CI
- Keycloak / SSO
- Firebase
- Fastlane
- nginx
- Google Play Console
- App Store Connect
Methods & Process
- Scrum
- SAFe
- TDD
- Pair programming
- Team leadership
- Technical consulting
Fullstack & Other
- TypeScript
- Java
- Spring Boot
- Kafka
- REST APIs
- Bluetooth / BLE
- AI / LLM integration
Work Experience
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2022 – Present
Kotlin Multiplatform Lead & Partner, Co-founder
Ernst & Conte GmbH, Baar, Switzerland
Co-founded a Swiss consultancy for Kotlin Multiplatform. I run projects end to end, from architecture and estimates to release, and handle the business side: proposals, budgets, and client relationships.
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2021 – Present
Senior Kotlin Multiplatform Engineer
Zürcher Kantonalbank (ZKB), Zürich, Switzerland
I lead the cross-platform architecture of frankly 3a, the bank's pension app. The shared KMP modules I design serve both the Android and iOS apps, which removes duplicate work on every feature. I also write the Swift code where the shared modules meet the iOS app.
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2022 – 2023
Kotlin Multiplatform Consultant
Toyota Group (Motix), London, UK
Designed and built a white-label KMP SDK for a connected-vehicle platform, consumed by a React Native frontend. Wrote the low-level Bluetooth (BLE) communication layer once in Kotlin for both iOS and Android, built telemetry collection, and was the primary technical contact for product stakeholders. The SDK shipped on schedule.
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2022
Kotlin Multiplatform Consultant
Almer Technologies AG, Bern, Switzerland
Reviewed the Android and KMP codebase of an AR smart-glasses startup and advised on module structure and shared-code strategy. The team adopted the recommendations right away.
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2019 – 2021
Mobile Software Engineer
ti&m, Zürich, Switzerland
Built Android and KMP features for Swiss banking and insurance clients, including the Helsana+ health insurance app and the LGT private banking platform. Maintained the shared KMP modules and worked with client stakeholders in Scrum teams.
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2017 – 2018
Business Management
Saeki Japan Co. Ltd., Fukuoka, Japan
Managed international client relationships and export operations in Japanese, English, and German during my year in Japan.
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2016 – 2018
President, students.fhnw
FHNW, Brugg, Switzerland
Led the university's student organisation, representing around 12,000 students. Restructured the organisation, coordinated initiatives across departments, and was responsible for events and the budget.
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2016 – 2018
Student Member, University Board
FHNW, Brugg, Switzerland
Represented the student body on the FHNW University Board and brought student interests into strategic and policy decisions.
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2014 – 2015
Software Engineering Intern
RUF, Schlieren, Switzerland
Built a Java test-automation system for quality assurance across software and hardware. Designed the testing model, wrote the test scripts, and debugged issues across the stack, including hands-on hardware work.
Ernst & Conte GmbH
Together with Patrick Del Conte I run Ernst & Conte, a Swiss software consultancy for Kotlin Multiplatform, app development, and fullstack engineering. I also created Tessa, our testing product that runs plain-language test scenarios on Android, iOS, web, and desktop. If your project needs a team rather than a single engineer, that's the door to knock on.
Visit ernstconte.chEducation
B.Sc. Computer Science
University of Applied Sciences and Arts Northwestern Switzerland (FHNW)
Focus on software development: algorithms, data structures, databases, web development, and software engineering.
International Business Management
Seinan Gakuin University, Fukuoka, Japan
Self-organised exchange year in Japan. Courses in business management, business communication, and economics.
Commercial Professional Baccalaureate (IMS)
BBBaden, Cantonal School Baden
Computer science track with the Swiss Certificate of Competence in computer science.
Interests
Away from work I boulder, play squash, garden, and ride motorbikes. I keep up my Japanese, a habit from my year in Fukuoka, and tinker with IoT and LLM projects at home.
Kotlin Multiplatform FAQ
The questions clients and teams ask me most often.
What is Kotlin Multiplatform (KMP)?
Kotlin Multiplatform is a JetBrains technology for sharing Kotlin code across Android, iOS, desktop, web, and the server. Business logic, API clients, data models, and validation live in one common module, and every platform runs that same code.
How is KMP different from Flutter or React Native?
Flutter and React Native share the UI layer. Flutter draws its own UI, and React Native runs your app through a JavaScript runtime. KMP shares what sits underneath: networking, persistence, business rules. Each platform keeps its fully native UI, SwiftUI on iOS and Jetpack Compose on Android. And if you want shared UI as well, Compose Multiplatform adds that on top.
Is KMP production-ready? Who uses it?
Yes. KMP is stable and backed by JetBrains and Google. Netflix, McDonald's, Forbes, and Cash App ship it in production. Swiss banks and insurers do too. I've built KMP modules that run in the frankly 3a and Helsana+ apps.
What does adopting KMP look like in an existing project?
You don't rewrite anything. Start with one shared module, often the networking layer or a set of data models, consume it from the existing Android and iOS apps, and grow from there. From the first shared module on, that code is written and maintained once instead of twice.
More answers in the full KMP FAQ, or ask me directly.
Get in Touch
Send me a message about a project, a role, or a KMP question.
What Happens Next
I read every message myself and aim to reply within a business day. You'll get an honest answer, including when I think KMP is not the right fit for your case.
Projects That Need a Team
For project work with a full team behind it, contact Ernst & Conte.