Kotlin App Development Company: Native Android Apps in Kotlin, Java Migration and Kotlin Developers You Can Hire

Updated October 2026 · Written and maintained by the Progression Agency strategy team

A Kotlin app development company builds Android apps in Kotlin, the language Google recommends for Android, with Jetpack Compose for the interface. We design, build and publish native Android apps in Kotlin and Compose, migrate older Java apps to Kotlin screen by screen, and provide Kotlin developers who join your team. This page explains when Kotlin is the right choice, what Kotlin Multiplatform shares across Android and iOS and when React Native or Flutter fits better, how to hire Kotlin developers, and why we quote after a written scope. We work with companies in all 50 states and worldwide, remotely.

What does a Kotlin app development company build?

Mostly native Android apps: the screens, the logic behind them, the connection to your servers and the release on Google Play, all written in Kotlin. Kotlin mobile app development also reaches into shared modules and into the Android side of larger products, which is where the questions below start.

What is Kotlin app development?

Kotlin app development is building apps, libraries and shared modules in the Kotlin language. On a phone that usually means an Android app, written in Kotlin and run on the Android runtime. Kotlin can also compile for other targets, which matters when a team wants logic shared with an iPhone app; the multiplatform sections below take that up.

Native Android apps in Kotlin and Jetpack Compose

Jetpack Compose describes each screen as code that reacts to the app’s state, so a change in the data redraws the interface without manual wiring. Google calls it Android’s recommended toolkit for native UI at developer.android.com/compose, and it is written with Kotlin APIs. Jetpack Compose app development is how we build new screens, and the broader Android picture sits on our Android app development page.

Where Kotlin stops: iOS screens, web front ends and servers

Kotlin is not a single answer for every layer. An iPhone app still needs an iOS shell and, in most designs, Swift screens. A web front end is usually written in JavaScript or TypeScript. A server can use Kotlin, but that is a separate decision covered near the end of this page. Naming those edges early keeps a Kotlin plan honest.

Our Kotlin app development services

Kotlin app development services at Progression cover five kinds of work: new Android apps, Compose interfaces, migration of older apps, Google Play release and updates, and dedicated developers. Kotlin development services are scoped one project at a time.

New Android apps in Kotlin

A new app starts from a written scope: the screens, the data it needs, the integrations, the Android versions and the markets where it will be released. From there the work runs in sprints, and each one ends with a build you can install on a phone. Starting in Kotlin from the first commit avoids a later conversion.

Compose interfaces and design systems

A design system in Compose is a small set of colors, type styles, spacing and reusable components that every screen draws from. It keeps a growing app consistent and makes a later redesign a change in one place. The visual work behind it is the subject of our UI and UX design service.

Publishing and keeping the app current on Google Play

Publishing means more than uploading a build. We set up the Play Console, complete the data safety form, prepare the store listing, run closed testing and release, and then keep the app current after Google Play approval as Android and the store rules move on.

Why does Android use Kotlin?

Because Google steers new Android work toward it. Android’s own guidance says it is making Android development Kotlin-first and recommends starting new apps in Kotlin, and the language removes whole classes of everyday mistakes.

Google’s Kotlin-first guidance

The Kotlin-first page on Android Developers recalls the Google I/O 2019 announcement that Android development would become increasingly Kotlin-first. It says new tools and content, such as Jetpack libraries, samples and training, are designed with Kotlin users in mind while Java access to the APIs continues. A feature table on that page marks Jetpack Compose and the Kotlin-specific coroutine APIs as Kotlin-only.

Null safety, coroutines and less boilerplate, in plain terms

Three language features explain most of the preference. Null safety: in Kotlin a variable cannot hold null unless its type allows it, so the compiler flags the mistake that crashes so many Java apps; the null safety guide lists the few places a null pointer error can still appear. Coroutines: they let code that waits on the network or a database read in order, as the coroutines overview describes, without blocking a thread. Less ceremony: data classes and concise syntax cut the code that exists only to satisfy the language.

Is Kotlin good for mobile app development?

For Android, yes, and it is the default choice for new projects. Kotlin is a practical language with strong tooling in Android Studio and first-class support in Jetpack. For iOS the answer is different: Kotlin can share code with an iPhone app, but the iOS shell is separate, as the Kotlin Multiplatform section explains.

Is Kotlin or Java better for Android?

Kotlin, for new work. Kotlin vs Java for Android is rarely a close call today, because Kotlin or Java for Android no longer means choosing one forever: the two live side by side in the same project.

Kotlin and Java in one app

The two languages can sit in one codebase. The Android Kotlin guidance describes Kotlin as fully interoperable with Java, so you can have as little or as much Kotlin as you want, and the Kotlin documentation explains how existing Java code is called from Kotlin. A few edges need care, such as values that come from Java without null information, which is why a conversion is reviewed rather than trusted blindly.

When Java code can stay as it is

Stable Java code that rarely changes and passes its tests has no urgent reason to move. Rewriting it adds risk with no user benefit. We usually advise leaving such modules alone, writing new features in Kotlin and converting a Java file when it needs real changes.

Will Kotlin replace Java?

Nobody can promise that, and we do not predict it. What can be said today is narrower: Kotlin is the recommended language for new Android apps, while Java continues to power servers and a great deal of older Android code. If your server side is Java, our Java development company page covers that work.

Java to Kotlin migration for an existing Android app

A Java to Kotlin migration moves an app to Kotlin in stages while it keeps shipping. The aim is a codebase new developers can read, not a rewrite that pauses releases. Many teams ask how to migrate an Android app to Kotlin without a freeze, and the answer is in small steps.

Screen by screen, module by module

Older Java or XML-layout apps can be moved to Kotlin and Compose one screen at a time. Android Studio helps with the mechanical part: the guide to adding Kotlin to an existing app covers setting up Kotlin in the project and converting a file, and warns that converted code usually needs a follow-up pass. Typical follow-ups replace blunt non-null assertions with safe handling of missing values.

Tests first, then conversion

Before a screen is converted we want tests around its behavior, so the converted version can be checked against the old one. Where tests do not exist, adding them is part of the written scope. A conversion that users cannot tell happened is the goal.

Meeting Google Play’s target API level in the same pass

Google Play requires new apps and updates to target a recent Android API level. As read in October 2026, the target API level page lists Android 16, API level 36, from August 31, 2026, with other levels for Wear OS, Android TV and similar devices and a path to request an extension to November 1, 2026. Raising the target level touches permissions and background work, so it is cheaper to plan it alongside the migration than to repeat testing twice.

Kotlin Multiplatform: what it shares and what stays native

Kotlin Multiplatform, often shortened to KMP, lets one Kotlin codebase serve Android, iOS and other targets while each platform keeps its own native layer. Progression’s cross-platform page covers the basics under what Kotlin Multiplatform shares; this section adds the decision detail. We present KMP as an option to evaluate with you, not as a default.

Shared business logic with native screens

The classic pattern shares the parts that behave the same on every phone: data models, networking, validation and rules, with each platform drawing its own screens. The Kotlin Multiplatform overview describes sharing isolated modules first and growing the shared part over time, and lets iOS screens be built in SwiftUI or UIKit. This is the shape most teams mean when they say Kotlin Multiplatform mobile.

Compose Multiplatform for shared screens

Compose Multiplatform extends Jetpack Compose so the screens can be shared as well. Its status differs by platform. On JetBrains’ Compose Multiplatform page as read in October 2026, iOS is labeled Stable, web is labeled Beta, Android runs on Jetpack Compose and desktop covers Windows, macOS and Linux, and the page calls it production-ready for mobile and desktop. Check that page again before you commit, because the labels change.

Can you develop iOS apps in Kotlin?

Partly. Shared Kotlin code compiles to native iOS binaries, so logic written once can run on an iPhone. The iOS app itself, with its project, signing and release, remains an iOS project, and its screens are either SwiftUI or UIKit or shared Compose Multiplatform screens. Can Kotlin run on iOS? Shared logic can; a whole iOS app written only in Kotlin is not the usual route.

Is Kotlin Multiplatform production ready?

Google states that Kotlin Multiplatform is stable and production-ready, and officially supports it for sharing business logic between Android and iOS. Production ready is a statement about the technology, though, and a team still has to be ready for it.

What JetBrains and Google say about stability

The Android page on Kotlin Multiplatform says it is officially supported by Google for sharing business logic between Android and iOS, and calls it stable and production-ready. It adds that you can choose how much to share, from core logic to the whole application, and that many Jetpack libraries are being made KMP-ready with support varying by platform. JetBrains describes the technology and the UI layer on its own pages; the two sets of labels are not identical, so read both.

Is Kotlin Multiplatform worth it for your team?

It is worth evaluating when three things are true: the Android team is strong in Kotlin, the app has real logic that would otherwise be written twice, and two native interfaces are acceptable. It is a poor fit for a small app with little logic or a team that knows only JavaScript. The evaluation we offer is a written recommendation before any estimate.

Who uses Kotlin Multiplatform?

JetBrains keeps a page of Kotlin case studies where companies describe their own use, filterable by Kotlin Multiplatform, backend and AI. We name no company here; read each story in the company’s own words and compare its app, its team and its constraints with yours.

Kotlin Multiplatform vs Flutter vs React Native

Choose by your team and your screens. Kotlin Multiplatform vs Flutter is a question about whether the interface is shared, and Kotlin Multiplatform vs React Native is mostly a question about which language your team already writes.

When Flutter fits better

Flutter is open source, uses Dart, and builds mobile, web and desktop apps from one codebase, according to flutter.dev. It fits teams that want one custom-designed interface everywhere and have no large Android codebase to protect. Our Flutter app development page has the detail.

When React Native fits better

React Native lets a team write apps in JavaScript with React and renders them with native platform components, as the React Native site puts it. It fits JavaScript teams and products that also have a web app. See React Native development, and React Native or Flutter when those two are the real contest.

When native Kotlin plus Swift is the honest answer

When the app leans on cameras, Bluetooth, sensors or platform features that arrive first on one operating system, two native apps are usually the straightforward route. It costs more to build twice but avoids a layer of translation. See native app development.

Kotlin mobile app development for business apps

Kotlin suits business apps that live on devices people carry through the working day. Three patterns come up most: field apps that work without signal, companion apps for wearables and connected devices, and apps that use AI.

Offline field apps for crews and inspectors

An inspector in a basement has no signal, so the app has to save forms, photos and signatures on the phone and send them when a connection returns. That means a local database, a queue of pending changes and clear rules for conflicts. Android’s recommended storage libraries, Room and DataStore, are named on the Wear OS getting-started guide as the same ones used on phones. Larger rollouts belong with our enterprise app development work.

Wear OS and connected-device companions

A watch app is its own Android app, built in Android Studio. Google recommends Compose for Wear OS for the interface, with libraries made for the small round screen. Phone apps that talk to hardware are a related design problem. See wearable apps and IoT apps.

On-device and cloud AI in a Kotlin app

Two design questions come first: does the model run on the phone or on a server, and what leaves the device. On-device work can run offline and keeps data local; cloud models can be larger and are easier to update. Which fits depends on the feature, the data and the budget, and our AI app development page goes further.

Hire Kotlin developers: a dedicated developer or a team

To hire Kotlin developers through Progression you choose between one dedicated developer who joins your team and a Kotlin team that owns delivery. Companies that want to hire a Kotlin developer for a single feature can use either route; people searching for Kotlin developers for hire are usually deciding between those two shapes.

A dedicated Kotlin developer inside your team

To hire dedicated Kotlin developers, the model is the one on our dedicated developers page. The engagement is monthly and scalable, the developer works in your tools and hours for real-time collaboration, work is covered by written IP assignment, a paid trial comes first, and senior oversight covers code review and standards. Mobile engineers on that page include iOS, Android, React Native and Flutter.

A Kotlin team that owns delivery end to end

When you would rather not manage engineers at all, a delivery team takes the app from scope to release. That is the model described on our app development agency page, with a build you can install at the end of every sprint.

Hiring remote Kotlin developers

Teams that hire remote Kotlin developers need a shared working day, access to the repository and clear review rules more than a shared office. We work remotely with companies in all 50 states and worldwide. The terms are on the hire dedicated developers page, and the Android skills are on hire app developers.

How to hire Kotlin app developers: what to test

To hire Kotlin app developers well, test what they will actually do: read an existing app, change it safely and ship. A short paid task beats a whiteboard puzzle.

Skills to check

Look for Kotlin itself, coroutines and Flow, Jetpack Compose, testing habits, Gradle builds and Google Play release. Our list of skills to test in an Android developer covers the platform side. A developer who has never read Java will struggle in most real apps, because older code is still in them.

A paid trial task instead of puzzles

Give the candidate a small, real change in a copy of your codebase and pay for the time. You see how they read code, ask questions and test their work. Our dedicated engagement also begins with a paid trial for the same reason.

Warning signs in a Kotlin portfolio

No released apps you can install, no tests in the public code, samples that are all Java with a few Kotlin files, and answers that cannot explain why a screen was built the way it was. One of these alone is not decisive; several together are.

How to choose a Kotlin development company

Choose a Kotlin development company by what it has shipped and how it tests, not by how many logos it shows. A Kotlin app development company should be able to show a released app, explain its test approach in plain terms and hand over everything you pay for.

Questions to ask Kotlin development companies

Ask about released apps you can install, how they test on devices, who owns the signing keys and accounts, and where any Kotlin Multiplatform experience shows up in real code. Comparing Kotlin development companies on these four answers filters out most of the noise.

Should you use a Kotlin agency, a freelancer or an in-house hire?

A freelancer suits a small, well-bounded task. An in-house hire suits a product you will build for years. An agency suits a product that needs design, engineering, testing and release together. Our pages on app development outsourcing and software development outsourcing weigh the trade-offs.

How we deliver a Kotlin app

Four things shape a Kotlin project here, and each is described on our other pages in the same words: a written recommendation before the estimate, sprints that end in an installable build, testing on emulators and real devices, and a managed release.

A written recommendation before the estimate

On a choice such as native or shared code, you receive the recommendation in writing before any estimate, so the price is for a decision you understand. The same habit appears on our cross-platform app development page.

Sprints that end in an installable build

Every sprint ends with a build you can install, so progress is something you hold in your hand rather than a status line.

• A written recommendation before any estimate
• A build you can install at the end of every sprint
• Testing on emulators and real devices
• Play Console setup, data safety form, listing, closed testing and release

Testing on emulators, real devices and Firebase Test Lab

Apps are tested on emulators and on real phones that match what your customers carry. Cloud device labs add range; Firebase Test Lab is one, and its documentation now announces that the service is deprecated and will shut down on September 30, 2027, pointing to the Developer Device Platform on Google Cloud. The method stays the same whichever lab is used.

Play Console setup, closed testing and release

We handle Play Console setup, the data safety form, the store listing, closed testing and release. Requirements for new personal accounts are on Google’s testing requirements page: accounts created after November 13, 2023 need a closed test with at least 12 testers opted in continuously for 14 days before applying for production access. Our Google Play publishing requirements section keeps the wider list.

Who owns the code, signing keys and Play Console?

You do. The code, data and accounts belong to the client, and the accounts are set up in your company’s name so a change of vendor never leaves the app stranded.

Code and repository

You own the code. Keep the repository in your own organization from the first commit, because that is what makes a handover or a second opinion straightforward.

App signing keys and Play App Signing

Play App Signing is a Google service in which Google holds the key that signs the app delivered to users. You keep an upload key to sign what you send. Google’s Play App Signing help says you can let Google generate the app signing key or provide your own, and that a key you manage yourself cannot be reset if you lose it. Decide who holds what at the start.

Accounts in your company’s name

The Google Play Console account and the other accounts the app depends on belong to you. When a vendor or one engineer holds them instead, a change of vendor or a locked account can strand the app, so ask every vendor where each account lives.

Kotlin on the server: when the app needs a backend

Many apps need a server, and Kotlin can run there too. This section is education, not a service claim: it explains the choice so you can decide the API language separately from the app.

Choosing the API language separately from the app

Ktor, from JetBrains, is a framework for building asynchronous servers and clients in Kotlin, and Spring Boot documents Kotlin support in its Kotlin guide. A Kotlin server lets mobile and backend developers share a language, but a team can just as sensibly keep Java, Node.js or Python. Our Kotlin on the server note and backend development page cover the options.

APIs the app depends on

An app is only as dependable as the interface behind it: versioned endpoints, clear error responses and a way to retire old app versions gracefully. See our API development page for how that is built.

How AI assistants answer Kotlin and KMP questions

Buyers ask ChatGPT, Claude, Perplexity, Gemini, Copilot and Google’s AI Overviews which Kotlin app development company to trust and whether Kotlin Multiplatform is ready. Assistants repeat what pages state plainly, which is why dated, specific pages beat vague ones.

Answers that go stale: KMP and Compose status

Stability labels move. An answer that said web was experimental a year ago may be wrong today. Check the date of any answer, then check the JetBrains and Android pages directly before you decide.

Checking a vendor’s Kotlin claims

Ask for released apps you can install from Google Play, public code samples and case pages with dates. A claim you can open and test is worth more than a count of developers. Our custom software development page shows the written-scope habit we apply.

How much does Kotlin app development cost, and why is it scoped first?

Progression quotes Kotlin work after a written scope and publishes no figure for it here. The same Kotlin app development company can quote a small migration or a new product, and the difference is entirely in what the scope contains.

Why we quote after a written scope

The price follows the number of screens, the integrations, the offline needs, the devices to support and the markets for the release. A written scope lists those so the quote, and the change process after it, refer to the same page.

• Every screen and the flow between screens
• The services and data the app connects to
• What must work without a connection
• The Android versions and devices to support
• The markets and Google Play requirements for release
• What happens to the app after launch

Cost drivers specific to Kotlin projects

Existing Java code and its test coverage, the state of the design system, whether the backend is ready, and whether the app is to share code with iOS are the largest drivers. Kotlin app development cost moves up when any of them is unknown.

Market figures, labeled

Our app development cost guide holds published US price bands (market figures, not a Progression rate card). Use them for context only. To price your own app, ask for a free proposal.

More app development services

These pages cover the work that sits beside Kotlin app development.

• Native app development: Swift and Kotlin
• React Native development
• Flutter app development
• iOS app development
• Hire app developers
• App development agency
• MVP development for a first release
• Progressive web apps
• Cloud apps
• CI and DevOps
• Agile delivery
• Software consulting
• Healthcare apps
• Delivery apps
• App development tools

Frequently asked questions