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Hire Kotlin Developers for Android and Beyond

Engineers who write idiomatic Kotlin for Android apps, shared Kotlin Multiplatform modules and server code, hired monthly with a trial period.

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Kotlin talent for mobile and shared business logic

Kotlin started as the preferred language for Android, but many teams now use it to share business logic between Android and iOS with Kotlin Multiplatform, or to write backend services with Ktor and Spring. Hiring someone who understands coroutines, sealed classes, Flow and Gradle well enough to structure all of that cleanly is harder than finding a general Android developer.

Nexzem shortlists Kotlin developers based on where the language will be used in your stack. A team planning KMP gets developers who have shipped shared modules; a team with a Kotlin backend gets engineers who know Spring or Ktor. Each developer starts on a short trial and works inside your repo and process.

Build a team with Kotlin Developers

Pick roles and seniority, choose what they will work on, then send the brief. We come back with matching profiles.

Kotlin Developers, by seniority
  • Junior Kotlin Developer
    0
  • Mid-level Kotlin Developer
    1
  • Senior Kotlin Developer
    1
Round out the team
  • Android Developer
    0
  • Swift Developer
    0
  • Flutter Developer
    0
What they will work on

What our Kotlin Developers can do for you

Kotlin developers for Android apps, Kotlin Multiplatform and backend services, with a trial period.

  1. 01

    Android apps in Kotlin

    Feature development with Jetpack Compose, ViewModel, Hilt and Room, following clean architecture so features stay testable as the app grows.

  2. 02

    Kotlin Multiplatform modules

    Shared networking, storage and business rules compiled for Android and iOS, with platform-specific UI kept native on each side.

  3. 03

    Coroutines and Flow

    Restructuring callback or RxJava code into coroutines and Flow, with clear scoping and cancellation to avoid leaks and wasted network calls.

  4. 04

    Ktor and Spring backends

    REST and GraphQL services written in Kotlin with Ktor or Spring Boot, including authentication, database access and containerised deployment.

  5. 05

    Gradle and build speed

    Version catalogs, convention plugins, build caching and module splits that shorten build times and keep dependencies consistent across modules.

  6. 06

    Testing and static checks

    Unit tests with JUnit and MockK, UI tests with Compose testing, plus Detekt and ktlint rules wired into CI.

Why hire Kotlin Developers through Nexzem

  • Matched to your Kotlin use

    We screen for the area you need, Android, KMP or backend, rather than sending generic Kotlin profiles.

  • Short trial first

    Start with a trial period on real tickets, and only continue monthly once you are happy with the output.

  • Shared working window

    Developers keep hours that overlap with yours for standups, design reviews and quick unblock calls.

  • Flexible team size

    Add Kotlin engineers for a multiplatform rollout and reduce once the shared layer is stable.

  • IP protected

    NDA on request and 100% ownership of code, build scripts and artifacts for your company.

How to vet a Kotlin developer

Kotlin developers work in different worlds: Android apps, backend services with Spring Boot or Ktor, and shared code through Kotlin Multiplatform. Start by clarifying which you need, then test for idiomatic Kotlin rather than Java written in Kotlin syntax. Strong candidates use null safety deliberately, prefer immutable data classes, write clear extension functions and understand coroutines and flows well enough to explain cancellation and error handling.

For Android work, check experience with Jetpack Compose, lifecycle handling and modern architecture components. For backend work, look for knowledge of Spring or Ktor, database access and testing. In both cases, ask how they migrated or maintained Java code, since most real Kotlin projects still live alongside Java. Our Kotlin vs Java comparison covers the differences candidates should understand.

  • Idiomatic use of null safety, data classes and sealed types.
  • Solid understanding of coroutines, flows and structured concurrency.
  • Experience interoperating with existing Java code.
  • Testing with JUnit, MockK and coroutine test utilities.
  • Clarity on Android, backend or multiplatform focus.
  • Code reviews that show care for readability and naming.

Interview questions we use for Kotlin developers

Our questions check whether a candidate understands Kotlin's design rather than memorized syntax. We ask them to write short snippets, explain the behavior of tricky code and connect answers to projects they have delivered, adjusting the focus for Android, backend or multiplatform roles.

Strong answers mention trade-offs, such as when a sealed hierarchy becomes hard to extend, and draw on real incidents, like a leaked coroutine scope or a nullability bug from Java interop. We value candidates who say what they would check before answering over those who recite definitions confidently.

  • When would you use a sealed class instead of an enum, and why?
  • How does structured concurrency decide what happens when a child coroutine fails?
  • What is the difference between StateFlow and SharedFlow, and when do you use each?
  • How do you call Kotlin code safely from Java, including nullability and default arguments?
  • How would you share business logic between Android and iOS with Kotlin Multiplatform?
  • How do you test code that uses coroutines and timeouts?

In-house vs dedicated Kotlin developer

An in-house Kotlin engineer builds lasting knowledge of your product and team, which matters for long-lived platforms. Hiring takes time, though, and experienced Kotlin developers with both Android and backend depth are in high demand. A dedicated developer can start sooner, bring experience from several projects and be replaced or supplemented without a new recruitment cycle if your needs change.

Many teams use dedicated developers to accelerate specific work, such as a Java to Kotlin migration or a move to Compose, while in-house staff own architecture and long-term direction. Shared code ownership, documentation and pairing make sure knowledge stays in your codebase. For broader Android needs, our Android developers cover the full platform beyond the language itself.

Hiring Kotlin Developers: from first call to first commit

Every stage has an owner and an exit, so you always know where your hire stands.

  1. Stage 1

    Tell us where Kotlin runs

    Share whether the work is Android, KMP, backend or a mix, plus your current libraries and build setup.

  2. Stage 2

    Get relevant profiles

    We shortlist Kotlin developers with matching project history and summarise their strongest areas.

  3. Stage 3

    Assess the candidates

    Interview them, review code they have written, and give an optional short task in your repo.

  4. Stage 4

    Onboard the developer

    After the NDA, they get access to your repo, CI and chat, and run your build locally.

  5. Stage 5

    Begin the trial

    Work starts on trial and moves to a monthly engagement that you can scale as plans change.

Where Kotlin Developers make a difference

  • Java to Kotlin migration

    A company with a large Java Android app adds a Kotlin specialist who converts modules gradually, introduces coroutines in place of callbacks and keeps every release stable while the rest of the team continues shipping features.

  • Kotlin backend with Ktor or Spring

    A startup that already writes Kotlin for Android builds its backend APIs in Kotlin as well, sharing models and validation logic and letting engineers move between mobile and server work without switching languages.

  • Shared logic with Kotlin Multiplatform

    A bank keeps fully native iOS and Android interfaces but shares validation, calculations and networking through Kotlin Multiplatform, with a dedicated developer setting up the shared module, builds and tests for both platforms.

  • Compose migration for an existing app

    A product team moves its Android screens from XML layouts to Jetpack Compose one feature at a time, with a Kotlin developer building the shared design system components and guiding the rest of the team.

Tools our Kotlin Developers work with

Proven, well-supported tools chosen for your scale, budget and team, never for novelty.

  • Kotlin
  • Android
  • Spring Boot
  • Java
  • PostgreSQL
  • Firebase
  • Docker
  • GitHub Actions

Developers who work alongside Kotlin Developers

All 46 developer roles

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Hiring Kotlin Developers: FAQs

Something else on your mind? Ask a consultant and get a reply within one business day.

What decides the cost of hiring a Kotlin developer?

You are billed monthly per developer after a short trial period. Seniority, specialisation such as KMP or backend, and full-time or part-time hours set the rate. We share a fixed monthly quote after a free consultation.

Is Kotlin Multiplatform ready for production apps?

For sharing business logic, networking and storage, yes, many teams use it in production. We usually keep UI native and share the layers below it to limit risk.

Can a Kotlin developer work on our Java code?

Yes. Kotlin and Java interoperate fully, so developers can maintain existing Java and introduce Kotlin in new or refactored areas.

Do you provide Kotlin backend developers too?

Yes. If your services run on Ktor or Spring Boot, we shortlist developers with backend Kotlin experience, database work and deployment skills.

What if the developer is not the right fit?

Tell us during or after the trial. We replace the developer at no extra cost and help with the handover.

Do your Kotlin developers work on both Android and backend?

Some do, and we match profiles to your needs. Many of our Kotlin developers specialize in Android with Jetpack Compose, while others focus on backend services with Spring Boot or Ktor. For mixed roles, we look for candidates with proven experience on both sides.

How do you test a Kotlin developer's coroutine knowledge?

We ask candidates to explain structured concurrency, cancellation, dispatchers and exception handling, then review or write small coroutine-based snippets with them. Real examples from their past projects, such as handling timeouts or parallel network calls, show practical understanding.

We work with clients across the USA, UK, Australia, UAE, New Zealand and India.

Where we work

Tell us who you need on your team.

Share the role, stack and start date. We reply within one business day with matching profiles and next steps.

Book a free consultation+91-7302622997