The core of the work
Kotlin Multiplatform
Up to 80% of the code in common between Android and iOS.
Available for new projects from January 2027 · introductory calls open now
Gaetano Manuele Trefiletti
Android and iOS apps from a single Kotlin codebase.
I build with Kotlin Multiplatform and Compose Multiplatform: shared logic and UI, up to 80% of the code in common. I have shipped 4 apps on Google Play and the App Store as the sole developer.
Android same app
iOS same app
One Kotlin codebase. The same app on Android and iOS.
Stack
The same interface
Compose Multiplatform
One Compose UI, on Android and on iOS.
Cross-platform and UI
Kotlin, Java and the Android UI beside the shared code.
- Kotlin
- Java
- Jetpack Compose
- XML/Views
Architecture
Orderly code, easier to keep evolving.
- Clean Architecture
- MVVM
- MVI
Data and networking
Data and network calls in the same module.
- Ktor
- Retrofit
- REST
- Coroutines
- Flow
- RxJava
- Room
- DataStore
- Koin
- Dagger Hilt
Device
BLE, maps and downloads, in the shared code.
- Bluetooth Low Energy
- NFC
- Background downloads
- Maps and geolocation
Release and quality
From the build to publishing on the stores.
- Signing and publishing on Google Play and the App Store
- JUnit
- Gradle
- Git
- Agile/Scrum
Projects
Apps in production.
4 projects shown
SafeZone is a freelance Android app. Celebrly: site development for a digital-invitation business. Zenith is a business web app. Casa Summer is a holiday-home website.
Offer
Packages
One Kotlin codebase for Android and iOS, with Compose Multiplatform.
For two separate native apps
Assessment
3 days
€900
Code review, what to move to KMP and Compose Multiplatform, a plan and an estimate.
Book an introductory callRecommended
For the first shared piece
Pilot migration
12 days
€3,600
One real feature in shared code, UI included, working in both apps.
Book an introductory callFor startups and SMEs
New Android and iOS app
MVP in Compose Multiplatform
from about €6,000
On a quote.
Book an introductory callFor agencies and teams
Team reinforcement
4 days a month, or 8
€1,100€2,100
An Android, KMP, Compose Multiplatform or BLE specialist beside the team.
Book an introductory callNo long commitment
Ongoing support / Retainer
1 day a month
€300/month
Code review, an architecture second opinion, build, Gradle or Xcode issues, and help for the team on shared KMP and Compose Multiplatform modules. No long commitment.
Book an introductory callBase rate €300 a day, including one-off work. Ongoing support / Retainer: 1 day a month, €300/month, with no long commitment. I also take websites and web apps, on a quote. These figures are not a quote. Third-party services are excluded.
What might a website or a first app cost?
Brochure site: €1,500–2,400. An estimate of 5–8 days at €300, for a few responsive pages, content already ready and contact by email. Online shops, private areas and custom integrations are excluded.
First version of an app: €6,000–12,000. An estimate of 20–40 days at €300, for one defined main flow. Backend, payments, hardware and extra features are estimated separately.
These are budget examples based on estimated time, not quotes.
How do we work together?
A free introductory call, then an assessment, a pilot or a new app, and ongoing reinforcement if you need it. I work remotely, part-time, alongside my employment.
What if the project changes?
We look at the request before going ahead, and I tell you the effect on time and cost. We put it in the current phase, or later.
The path
How I work
From the call to shared code. We stop when the next step is not needed.
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Free introductory call
You tell me about the product and the code. We see whether a single Kotlin codebase is the right path.
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Assessment
Three days: code review, what to move to KMP and Compose Multiplatform, a plan and an estimate.
-
Pilot or new app
One real feature in shared code, UI included, or a new MVP in Compose Multiplatform.
-
Ongoing reinforcement
Four or eight days a month, if the team wants an Android, KMP, Compose Multiplatform or BLE specialist beside them.
What I can do for you
We start from what you need.
Android and iOS apps from one codebase. Websites come later, if you need them.
Book an introductory callAndroid and iOS apps in Compose Multiplatform
Logic and UI in the same Kotlin code, for Google Play and the App Store. We start from the code you have, or from scratch.
Websites and web apps
On a quote, when a website or web app is needed alongside the apps. Content, features and phone use are agreed first.
Reinforcement and maintenance
I join a team that is already moving, add features or look after the code. Part-time: four or eight days a month.
A bit about me
Mobile is my work. Curiosity does the rest.
I work as an Android and Kotlin Multiplatform developer in a product company. As a freelancer, part-time and remote, I write Android and iOS apps with a single Kotlin codebase and Compose Multiplatform.
I have 5 years of experience in Android and Kotlin. Italian is my native language, English is C1, French is intermediate.
The next step
Book an introductory call.
Send me two lines about the product. New engagements from January 2027, introductory calls open now.
Message me on WhatsApp
(opens in a new tab)
+39 345 234 3065
gaetano.trefiletti.gt@gmail.com
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