Kotlin development for
Android and JVM backends.
Kotlin is the default for native Android and a real improvement on Java for JVM backends. Null safety, coroutines, and far less boilerplate, fully interoperable with the Java ecosystem. We use it on both sides of a product.
Kotlin, on the phone and on the server
The two places Kotlin earns its keep: native Android apps that have to feel first-party, and JVM backends where you want Java's ecosystem without Java's ceremony.
Native Android Apps
Jetpack Compose UI, the newest platform APIs, and an app that behaves exactly like a first-party Android product. It is the language behind the Android side of EHEIM Digital Connect.
Spring Backends in Kotlin
The same Spring Boot ecosystem as Java, written in Kotlin: null safety, data classes, and coroutines instead of callback-heavy async.
Connected-Hardware Apps
Android apps that talk to real embedded devices over local networks and the cloud, with graceful handling when the connection drops. EHEIM was validated on Orange Pi and Raspberry Pi.
Java to Kotlin Migration
Incremental migration of an existing Android or Spring codebase, file by file, since Kotlin and Java run side by side in one project.
The JVM, without the boilerplate
Kotlin keeps everything good about the JVM and removes most of what made Java tedious. For Android there is no real alternative; for backends it is a clear upgrade.
Null safety in the type system
The compiler forces you to handle the absence of a value. An entire category of production crash, the null pointer exception, largely disappears.
Coroutines make async readable
Concurrent code reads top to bottom instead of nesting into callbacks. Structured concurrency means work is cancelled cleanly when it is no longer needed.
Full Java interoperability
Every Java library works. You can migrate a codebase one file at a time, and mix the two languages in the same module with no bridge.
Google's Android default
Android tooling, docs, and samples lead with Kotlin. Jetpack Compose is Kotlin-first. Building Android any other way is now the exception.
When should you choose Kotlin?
For Android it is close to automatic. For backends and cross-platform, the choice depends on your team and product.
Kotlin makes sense when
- You are building an Android-first native app
- You want a JVM backend without Java's boilerplate
- You are migrating an existing Java codebase gradually
- The app talks to embedded or connected hardware
Consider alternatives when
- You want one codebase across iOS and Android, where Flutter fits
- Your team is a JavaScript team, where React Native shares more
- The backend has no JVM context and a simpler stack works
What we pair with Kotlin
Kotlin on the client, the server, or both. Here is the stack around it.
Hire a Kotlin Developer
Skip the full build. Get a vetted Kotlin developer working inside your existing team, on your stand-ups and your roadmap.
Hire a Kotlin Developer →
Built by AI-native engineers, so your Kotlin app is ready for assistant features
On-device smart capture, streaming assistant panels, and agent-driven flows need the app architecture designed for them. We build the state, streaming, and coroutine patterns in from the start. It is how our own products, Tully AI and Mebag, were built.
Token streaming over coroutines and Flow, with cancellation and retry handled cleanly on a mobile connection.
Camera and voice input wired to a model with the right on-device and server split.
Prompt versioning, evals, and guardrails on the backend the app talks to.
See how we build AI into real products. Our AI development →
Common questions about Kotlin development
Straight answers on Android vs backend, Kotlin vs Java, Compose, cost, and how we start.
Do you build custom Kotlin applications, or can we hire a Kotlin developer to join our existing team?
Both. Most engagements are a fixed-price custom build. If you already have a team and need Android or backend capacity, we also place vetted Kotlin developers who work inside your workflow while we handle employment and payroll.
How much does Kotlin development cost?
We work fixed-price, not hourly. You get a fixed number and a fixed timeline before any code is written. A native Android app is a different figure from a Kotlin backend service. See our pricing page, or book a call for a real number.
How experienced is your team with Kotlin specifically?
We build in Kotlin for native Android and for JVM backends on Spring. It is the language behind the Android side of EHEIM Digital Connect, the smart-aquarium control app we are development partner on, validated on Orange Pi and Raspberry Pi hardware inside Android Studio.
Kotlin or Java for a JVM backend?
Kotlin for new services: null safety, coroutines, and far less boilerplate, while staying fully interoperable with the Java ecosystem and Spring. Java when the team is deep in it already and the churn of a language change is not worth it. The two mix freely in one codebase.
Kotlin or Flutter for a mobile app?
Native Kotlin when the app is Android-first, needs the newest platform APIs, or has to feel exactly like a first-party Android app. Flutter when you want one codebase across iOS and Android with a consistent custom UI. We build both and recommend based on the app.
Do you work with Jetpack Compose and coroutines?
Yes. Jetpack Compose for new Android UI, coroutines and Flow for async work, and the current Android architecture components. For existing apps on the View system we work with what is there and migrate incrementally where it pays off.
Is Kotlin a good choice in 2026?
For Android, it is the default and has been for years. For JVM backends, it is a genuine improvement on Java with no real downside. Where it is not the pick: a cross-platform app where Flutter or React Native fits better, or a team with no JVM or Android context and a simpler option available.
What does the process look like?
A 30-minute scoping call, then a fixed-price, fixed-timeline proposal within 48 hours.
Do you sign an NDA before we talk details?
Yes. We can have an NDA in place before the first call. Just ask and we will send one over.
Hire Kotlin Developers
Need Kotlin engineers embedded in your team rather than a full project handoff? Our Kotlin Developers join your existing workflow (your tools, your stand-ups, your roadmap) while we handle employment, payroll, and HR. Add one developer or a full team, scale up before a release and back down after, and keep everything they build.
Building for Android, or a JVM backend?
Tell us what you are building.
Native Android, a Spring service in Kotlin, or a migration off Java. We will scope it honestly and recommend the right approach.