Kotlin development company
Kotlin development services for Android apps built with Jetpack Compose, business logic shared across Android and iOS with Kotlin Multiplatform, and server-side Kotlin on Ktor or Spring Boot, including gradual conversion of existing Java code.
- Senior engineers · IST + EST overlap
- NDA on day 1
- 24-hour reply
- Projects shipped
- 50+
- Code ownership
- 100%
- Client rating
- 4.8/5
- First reply
- 24h
Kotlin across Android, shared code and servers
Krapton is a Kotlin development company that builds Android apps, Kotlin Multiplatform modules and JVM backends with one language and one set of engineering habits. On Android our engineers work in Jetpack Compose with ViewModels, Kotlin coroutines and Flow, Hilt or Koin for dependency injection, and Room for local storage. When a product also ships on iOS, Kotlin Multiplatform lets networking, validation, persistence and business rules live in a shared module while each platform keeps a native interface, or Compose Multiplatform shares the UI as well. On the server, Ktor suits lean services and Spring Boot suits teams that want its ecosystem, both with full Java interoperability. Kotlin is not the answer for every product: an iOS-only app belongs in Swift, and a team of web developers may move faster with React Native. We also convert Java codebases file by file, since Kotlin and Java compile side by side in the same module.
Kotlin development services
Jetpack Compose Android apps
Native Android apps written in Kotlin with Jetpack Compose, Material 3, Navigation, ViewModel and StateFlow, structured into feature modules that build quickly and test in isolation.
Kotlin Multiplatform modules
Shared Kotlin code for Android and iOS using Ktor Client, kotlinx.serialization and SQLDelight or Room, with expect/actual declarations for platform APIs and SKIE to make the Swift side pleasant to call.
Java to Kotlin migration
Gradual conversion of Java Android apps or JVM services, starting with tests and data classes, adding nullability annotations to remaining Java, and replacing callbacks or RxJava with coroutines.
Ktor and Spring backends
Server-side Kotlin with Ktor or Spring Boot, using coroutines for non-blocking I/O, Exposed or jOOQ for SQL, and containerized deployment with health checks and structured logging.
XML to Compose migration
Moving existing View-based screens to Jetpack Compose one screen at a time through ComposeView and AndroidView interop, so the app keeps shipping while the UI layer modernizes.
Build and release engineering
Gradle Kotlin DSL with version catalogs and convention plugins, KSP instead of kapt where libraries support it, baseline profiles for startup, and Play Console release tracks wired into CI.
Why teams choose Krapton for Kotlin
Senior engineers, fixed scope, and code you own — the things agencies promise and rarely deliver.
Coroutines used with discipline
Work runs in viewModelScope or lifecycle-aware scopes, never GlobalScope, with structured cancellation and injected dispatchers so background tasks stop when screens close and tests stay deterministic.
Null safety at the edges
Platform types from Java libraries and JSON payloads are validated at module boundaries, so the !! operator stays out of production code and crashes do not hide in casts.
Clear advice on multiplatform
We tell you whether Kotlin Multiplatform, Flutter, React Native or two native apps fits your team, based on existing skills, UI demands and how much logic is truly shared.
Testing built into modules
JUnit and kotlinx-coroutines-test for logic, Turbine for Flow assertions, Compose UI tests for screens, and Roborazzi or Paparazzi screenshot tests to catch visual regressions.
How a Kotlin project runs with Krapton
01
Platform and scope decision
We confirm Android-only, Kotlin Multiplatform or native-per-platform, define the module structure, and list the SDKs, APIs and minimum Android versions to support.
02
Architecture and data layer
Repositories, use cases and ViewModels are sketched with their coroutine scopes, offline caching rules and error handling before screens are built.
03
Feature sprints with builds
Each sprint ends with an internal testing build through Firebase App Distribution or Play internal testing, plus passing unit, UI and screenshot tests.
04
Release and observability
Staged Play Store rollouts are watched through Firebase Crashlytics and Android vitals, with Kotlin, AGP and library upgrades scheduled as routine maintenance.
The Kotlin stack we build with
Kotlin development: questions answered
What does a Kotlin development company build?
It builds Android apps, shared mobile logic and JVM services in Kotlin. At Krapton that covers Jetpack Compose apps, Kotlin Multiplatform modules used by both Android and iOS, Ktor or Spring Boot APIs, and migrations of Java code to Kotlin. Deliverables include the source, Gradle build logic, automated tests, CI pipelines, Play Console release setup and documentation of architecture decisions.
Is Kotlin Multiplatform a better choice than Flutter or React Native?
It is better when you want native UI on each platform and a shared core of business logic, or when you already have Android Kotlin code to reuse. Flutter suits teams that want one UI toolkit everywhere, and React Native suits teams with strong React skills. Kotlin Multiplatform asks iOS developers to consume Kotlin APIs, so we check how your iOS team feels about that before recommending it.
How do you migrate a Java Android app to Kotlin?
We migrate incrementally, because Kotlin and Java interoperate within the same module. New code is written in Kotlin first, then tests, models and utilities are converted, with Java code annotated for nullability so Kotlin callers see accurate types. Callback and RxJava chains move to coroutines and Flow, and View-based screens move to Compose where the payoff is clear. Releases continue throughout.
How do you keep a Kotlin Android app fast and stable?
We measure first, using Macrobenchmark, baseline profiles and Android vitals rather than guesswork. Common fixes include reducing unnecessary Compose recompositions with stable types and remember, moving disk and network work off the main thread with the right dispatcher, paging large lists, and shrinking the build with R8. Crashlytics and StrictMode in debug builds surface crashes and main-thread violations before users notice them.
What affects the cost of Kotlin development services?
Cost follows scope and platform choices. Key drivers are whether you need Android only or shared Kotlin Multiplatform code for iOS too, the number of screens and offline requirements, third-party SDKs such as payments or maps, the size of any Java codebase to migrate, backend work in Ktor or Spring, and compliance needs like data encryption. Discovery turns these into a scoped estimate.
Ready to build? Tell us what you have in mind.
Send a short brief and a senior engineer will reply within one business day with next steps — no sales fluff.