Hire Kotlin Developers

Expert Kotlin developers from Europe and North America. DevTeam.Space is a vetted community of expert Kotlin dev teams supported by an AI-powered agile process. Top companies and startups rely on us to build great Kotlin-powered mobile apps. We can help you too, by enabling you to hire and effortlessly manage expert Kotlin developers.

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Hire Expert Kotlin Developers,
Not Freelancers

Building a great product in today’s world requires expert developers, not freelancers. DevTeam.Space is a vetted community where you can hire senior Kotlin developers with relevant expertise.

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Our expert Kotlin developers deliver supportable and maintainable code. So any new developers you add to the team can onboard and continue working on the code immediately.

Top 10 Expert Kotlin Developers to Hire in 2023

Max | Web / Mobile Developer

 North America

Max has 9 years of experience in web & mobile development. He is committed to achieving the best results to ensure his projects are first-class.

  • AngularJs
  • Django
  • JavaScript
  • Python
  • SQL
  • AngularJs
  • Django
  • + 3 more

Andy | Android Developer


Andy has 8 years of experience in Android development, 2 of which were as a team lead. He is skilful in any part of Android development.

  • Android Kotlin
  • Android Kotlin

John | Android Developer


Android developer with 5 years of experience. The portfolio includes projects covering all aspects of Android's system.

  • Android Kotlin
  • Android Kotlin

Nikita | Android Developer


Nikita has over 5 years of experience as a mobile app developer. He specializes in Android Kotlin.

  • Android
  • Android Kotlin
  • Java
  • Android
  • Android Kotlin
  • + 1 more

Denis | Android Developer


Denis is a senior mobile app developer with 6 years of experience. He has worked in the education, healthcare, and banking industries. He is an expert in Kotlin and Java.

  • Android
  • Android Kotlin
  • Java
  • Android
  • Android Kotlin
  • + 1 more

Dmitry | Android Developer


Dmitry is a senior developer with 6 years of experience in mobile app development. He is an expert in Kotlin, Clean Architecture, and MVVM.

  • Android
  • Android Kotlin
  • Android
  • Android Kotlin

Alexey | Android Developer


Alexey is a senior mobile app developer with over 7 years of experience with Java and Kotlin. He worked on many complex projects, both as a developer and as a team lead.

  • Android
  • Android Kotlin
  • Java
  • Android
  • Android Kotlin
  • + 1 more

Sergey | Android Developer


Sergey has 7 years of experience in Android application development. His primary areas of expertise are Java and Kotlin.

  • Android
  • Android Kotlin
  • Java
  • Android
  • Android Kotlin
  • + 1 more

Roma | Android Developer


Roma is an Android mobile developer with 7 years of experience. He is an expert in numerous technologies including React Native and JavaScript.

  • Android
  • iOS
  • JavaScript
  • Node.js
  • React
  • ReactNative
  • Android
  • iOS
  • + 4 more

Kirill | Android Developer


Kirill has over 6 years of experience as a mobile application developer. The main technologies he works with are Java, Kotlin, Android SDK, AndroidX, and Dagger 2.

  • Android
  • Android Kotlin
  • Java
  • Android
  • Android Kotlin
  • + 1 more

How to Hire Kotlin Developers Through DevTeam.Space

Submit a Hiring Request With Zero Risk

Submit a Hiring Request With Zero Risk

Your dedicated tech account manager will then contact you to assess your needs in detail and share our relevant Kotlin expertise.

Get Top Kotlin Developers

Get Top Kotlin Developers

Kotlin developers with relevant expertise will be presented for your review. Once approved, we set up the process and get started.

Experience World-class Development Process

Experience World-class Development Process

Get supportable and maintainable code, easily communicate, track developers’ performance and payments, and receive daily updates.

Expect the Highest ROI

Expect the Highest ROI

Once satisfied with our exceptional quality and dedication, you can easily hire more Kotlin developers to scale your team.

How to Interview and Hire Kotlin Developers

Kotlin Developers
AI Expert | Developer | Writer | Photographer

Native Android developers love Kotlin, something which has made it one of the world’s top programming languages.

This powerful open-source language grew steadily in popularity after its launch back in 2011, however, it made a gigantic leap in 2018 to become one of the world’s most popular programming languages upon the release of v 1.2, a version that turned it into a multi-platform language.

Its many advantages are why it is so highly sought-after among the most important Android programming languages. To start with, Kotlin supports both object-oriented and functional programming. It’s fully interoperable with Java. It targets Java Virtual Machine (JVM), furthermore, you can have both Kotlin and Java code in the same project.

Kotlin offers both powerful features and great performance. With Kotlin, you can achieve more with less code. You can easily read Kotlin code, and consequently, you can easily maintain Kotlin apps.

Extensive development and testing make Kotlin apps the most reliable out there. The language has a vibrant developers’ community and a bright future.

It is not surprising then that lots of developers are learning Kotlin. However, the demand for Kotlin app development is also growing rapidly. Therefore, hiring Kotlin app developers can be hard. As a bit of a shortcut, you can hire senior Kotlin developers from Europe and North America by submitting a free hiring request to DevTeam.Space.

There are lots of ways to hire expert Kotlin developers. You need to choose the right hiring platform first. Hiring freelance Kotlin developers might be a tempting idea to try to save money. However, professional Kotlin developers outsourced from a dedicated software development company dramatically improve your chances of success when undertaking complex projects.

You will need to understand your desired skill requirements before hiring Kotlin developers. Proficient Kotlin developers need the following skills:

Primary Kotlin development skills

Kotlin app developers need the following primary technical skills:

  • Sound knowledge of Kotlin;
  • Good understanding of the features and capabilities of Kotlin;
  • Extensive experience in developing Android applications;
  • Robust understanding of object-oriented programming (OOP);
  • Good understanding of functional programming;
  • Familiarity with front-end design and development;
  • Experience in working with IDEs (integrated development environments) like Android Studio;
  • Familiarity with testing tools like Espresso;
  • Knowledge of testing and DevOps processes, methods, tools, and practices;
  • Kotlin offers coroutines to handle asynchronous programming. Understanding of how to use coroutines for managing concurrency and background tasks is essential;
  • Strong knowledge of data structures and algorithms is crucial for writing efficient and optimized code, especially when working on performance-critical applications;
  • Proficiency with version control systems like Git is essential for collaboration and code management;
  • Understanding common design patterns such as Singleton, Observer, Factory, etc., helps in writing maintainable and scalable code;
  • Knowledge of clean code principles, SOLID principles, and code refactoring techniques will help you write more maintainable and readable code;
  • Familiarity with dependency injection frameworks like Dagger or Koin can improve the modularity and testability of your code;
  • Understanding the software development lifecycle, agile methodologies, and project management concepts will help you collaborate effectively with all members of the development team.
  • Conceptual understanding of functional requirements and non-functional requirements (NFRs);
  • Knowledge of software architecture and key architectural patterns;
  • Understanding of software development lifecycle and development methodologies like agile.

Other software development skills

Look for the following additional software app development skills when you hire Kotlin app developers:

A. Application security skills

You need to prioritize application security since most industries are highly regulated. If you plan to target these industries with your app, then application security is critical.

You can use various security approaches, however, hiring Kotlin app developers with the right skills is crucial. Look for Kotlin programmers that know how to use the security features of Kotlin effectively.

Kotlin developers need to know about encryption, API security, security testing, compliance testing, etc. They should explore tools like antivirus, firewalls, and digital signatures to enhance application security.

A good understanding of and experience developing the following is also essential:

  • Secure Authentication (2FA – Two-Factor Authentication)
    Secure authentication is essential to ensure that only authorized users can access sensitive parts of an application or perform certain actions. Two-Factor Authentication (2FA) adds an extra layer of security by requiring users to provide a second form of authentication, such as a one-time code sent to their mobile device, in addition to their usual password. This helps protect against unauthorized access even if the password is compromised.
  • Authorization and Access Control
    Authorization and access control are crucial in defining what actions and data a user is allowed to access within the application. Properly implementing authorization prevents unauthorized users from accessing sensitive information and helps enforce security policies.
  • Jailbreak and Root Detection
    Jailbreaking (on iOS) and rooting (on Android) refer to the process of removing device restrictions to gain privileged control. These activities can compromise the security of an application and the device it runs on. Detecting if a device is jailbroken or rooted allows the application to take appropriate measures, such as restricting certain functionalities or denying access altogether.
  • Input Validation
    Input validation is essential to protect against various types of attacks, such as SQL injection, Cross-Site Scripting (XSS), and other forms of injection attacks. By validating and sanitizing user inputs, developers can ensure that the application only accepts legitimate and safe data, reducing the risk of security vulnerabilities.

Implementing these skills in Kotlin development helps build secure and robust applications, safeguarding user data and providing a better user experience. Security is a critical aspect of software development, and by integrating these practices into the development process, developers can mitigate potential risks and ensure their applications are resilient against attacks.

B. Code review

You need experienced developers that can review Kotlin code written by other developers. Code review is important since it enables you to detect defects early in the lifecycle.

Code review requires a structured and systematic approach, and you need expert developers to do it properly. All of our developers at DevTeam.Space have been trained to undertake code reviews. This means those companies that outsource our developers can rely on them to undertake thorough code reviews.

C. Good communication and team skills

Nowadays, it’s impossible to build a great product with just one developer so Kotlin developers need specific additional competencies. We often call them “soft skills”. These competencies are as follows:

  • Communication skills
    Software app development involves abstractions, and communication is key to successfully navigating them. Communication skills are even more important for remote programmers.
  • Teamwork
    Developers need to work effectively in a team. They also need to collaborate with your existing team. Teamwork is important for this.
  • Passion for excellence
    You need to offer the best app to your users since the mobile application market is competitive. Such excellence requires dedication on the part of developers.
  • Empathy
    Successful Kotlin app developers understand the requirements of end-users from their perspective. This requires empathy.

How to find the best Kotlin developer?

You now know the main skills that Kotlin app developers need, therefore, you ought to start the hiring process. Take the following steps to hire Kotlin app developers:

1. Decide what kind of platform to hire Kotlin developers

You need to choose the right platform to hire Kotlin mobile app developers. The reason for this is simple, to ensure the success of your project, you need the best team.

Can your in-house team do the job for you? If it can’t deliver the project due to skill gaps or lack of bandwidth, then you need to hire remote Kotlin developers. Partnering with Kotlin developers with the required skills and competencies will ensure your project is a successful one. On the other hand, hiring incompetent people puts the entire project at risk.

The choice of hiring platform makes a big difference. You might think that hiring low-cost freelancers on an hourly basis will suffice. This approach can work on a hobby project but not on a complex one.

Complex projects need highly knowledgeable developers with extensive experience, however. You might find it hard to hire such developers on freelance platforms.

Firstly, it can be very hard to assess the actual expertise of freelancers. Freelancers also only work part-time on your project. It is often hard to manage part-timers even when they are co-located. It’s even harder with remote workers.

Freelance platforms don’t provide any management support. What if freelancers leave your project mid-way and take your code? You need to hire replacement developers, and that’s entirely your headache.

We recommend you hire dedicated developers from trustworthy software app development companies offering Kotlin development services that include outsourcing their Kotlin developers or Kotlin development teams. DevTeam.Space is one such company. This approach suits medium or high-complexity Android development projects.

What if you need a whole Kotlin development team and not just individual developers?

Companies like ours provide highly skilled, experienced, and motivated developers. We can even develop your project entirely in-house, should you want us to take the hard work off your hands. Our data-driven project management and development processes make it easier for your project manager to follow the project development every step of the way.

Hire the best talent from DevTeam.Space if you plan to deliver first-class medium-to-high complexity Android projects.

2. Interview the shortlisted candidates

Ok, so you have initiated the hiring process. A number of developers have sent you their resumes. You need to interview them. Request help from colleagues or friends if you don’t have sufficient Kotlin skills.

You can also review interview questions on the Internet or get in contact and request one of our experts help you. Note: You won’t need to do such an extensive interview when you outsource developers from a software development company as their developers are all full-time with the company.

Go beyond general theoretical Kotlin expertise. Look for candidates that know the ins and outs of the native Android app development process. Assess how they used the powerful features of Kotlin for developing mobile apps in the past. Ask to see examples.

Describe your project requirements to candidates. Ask them about how they will solve specific project problems. Expect to hear specific or unique ideas, and watch out for candidates using only jargon rather than giving accurate solutions to your questions.

3. Provide detailed information about your application development project

You have selected your Kotlin developers, and you now need to onboard them. Successful project completion requires developers to be productive. Effective onboarding is key to productivity.

Explain your business needs and project requirements to the new developers. Provide them with relevant project documents like requirements, technical solutions, etc. Also, take time to explain your technical solutions and architecture to your new developer or team.

Provide access to the project’s technical environment. New developers need access to the code repository and other tools.

Introduce your new developers or team to your existing team. Explain their roles and responsibilities. Describe your governance model to your new team members.

Take your new developers through your project plan. Describe the milestones, furthermore, explain the deliverables and timelines. Set up a communication process and establish accountability. Start them going and monitor their performance and output.

Interview tips to hire Kotlin developers

We offer the following tips for hiring Kotlin app developers:

A. Look for Kotlin app developers that know the important features of the language

A modern programming language offers a wide range of features. Developers only use the most relevant features though. They don’t need to know every little-known feature offered by a language.

Take the example of Kotlin. You can implement many functionalities in Kotlin by writing less source code compared to other languages. The same code written in an older language can’t achieve the same functionality.

You should look for developers that know about such important capabilities of Kotlin. Don’t expect Kotlin programmers to know every obscure feature offered by the language, but they should know libraries such as SKL, Room, Retrofit, Glide, Anko, and Koin. Android Jetpack and ViewBinding expertise is very important.

If you hire developers who have used these libraries before to build functionalities similar to your desired ones, you should be able to guarantee they will know the required features to make yours a success.

B. Hire Kotlin app developers from flexible service providers

To hire Kotlin developers, choose service providers that offer flexible hiring models. Companies offer different options to clients looking to hire professionals. For example, typical offerings include fixed prices, time and material, etc. Keep in mind that you need to factor in time and cost overruns, etc., before choosing your preferred model.

You need to evaluate these offerings thoroughly. Ask probing questions and don’t rely on the claims made by their sales team. Talk to businesses that have hired from the providers earlier and read as much feedback as possible from sites like Clutch, etc. You can see our DevTeam.Space reviews on Clutch here.

C. Look for a competent team leader if you hire remote developers

Many companies hire remote software developers, and you can do that too. Remote programmers have made a huge impact on the global software development landscape. You get access to a global talent pool by hiring remote developers, meaning you can source the right people for your project.

However, managing remote application developers can be hard. Time zone differences make it harder. A capable and experienced team leader in a remote work team can help though. Such a team leader reduces management overheads. Look for a smart team leader when hiring remote teams.

Note: Companies like DevTeam.Space assign experienced account managers who have technical expertise and have managed similar projects and teams before. They will ensure your project’s success at no additional cost to you when you hire 1 or more developers. Your dedicated account manager will help your project manager in any way they need while also closely monitoring the performance of the outsourced developers.

Examples of coding questions to ask during the interview when hiring Kotlin application developers

Ask questions that help you assess the hands-on skills of developers. The following are a few examples:

1. Asynchronous Programming

You are building a Kotlin application that makes multiple network requests concurrently using Kotlin coroutines. How would you ensure that all the network requests are executed in parallel and collect their results efficiently? Provide an example code snippet that demonstrates the use of Kotlin coroutines for asynchronous network requests.


To ensure that the network requests are executed in parallel and their results are collected efficiently, you can use the async coroutine builder along with awaitAll function. The async builder starts a new coroutine for each network request, and awaitAll suspends the coroutine until all requests are completed.

import kotlinx.coroutines.async;
import kotlinx.coroutines.awaitAll;
import kotlinx.coroutines.runBlocking;

fun main() {
  runBlocking {
    val request1 = async { makeNetworkRequest("https://api.example.com/data1") }
    val request2 = async { makeNetworkRequest("https://api.example.com/data2") }
    val request3 = async { makeNetworkRequest("https://api.example.com/data3") }

    val results = awaitAll(request1, request2, request3)

suspend fun makeNetworkRequest(url: String): String {
  // Simulate network delay
  // Perform the network request and return the result
  return "Result from $url"

2. Compatibility with Java

Explain how Kotlin ensures compatibility with Java code and libraries. What are the key features in Kotlin that facilitate seamless interoperability with Java, and what considerations should developers take into account when using Java libraries in Kotlin projects?


Kotlin is designed to be fully compatible with Java, which means Kotlin code can call Java code and vice versa without any issues. Key features that facilitate compatibility with Java include:

  • Null Safety: Kotlin’s nullable types allow it to differentiate between nullable and non-nullable references, which helps avoid null pointer exceptions when interacting with Java code that might return null.
  • Extension Functions: Kotlin allows defining extension functions on existing Java classes, even those without modifying the original Java code. This enables Kotlin developers to add utility functions to Java classes.
  • Java Interoperability Annotations: Kotlin provides various annotations like @JvmStatic, @JvmOverloads, and @JvmName that help fine-tune the way Kotlin code is compiled to Java bytecode to ensure seamless interoperability.
  • When using Java libraries in Kotlin projects, developers should consider the following:
  • Nullability: Be mindful of null safety when calling Java methods that can return nullable types.
  • SAM Conversions: Kotlin supports SAM (Single Abstract Method) conversions, allowing Kotlin lambdas to be treated as functional interfaces in Java libraries.
  • Platform Types: Some Java libraries might use platform types, which means Kotlin cannot guarantee null safety or type inference for those types. Extra caution is needed when working with platform types.

3. Testing with JUnit 5

You are working on a Kotlin project and need to write unit tests using JUnit 5. Explain how you can use JUnit 5 features such as parameterized tests and nested tests in Kotlin. Provide an example code snippet to demonstrate the implementation of both parameterized and nested tests.


JUnit 5 provides powerful features for writing expressive and organized tests in Kotlin:
Parameterized Tests: In Kotlin, you can use JUnit 5’s @ParameterizedTest annotation to perform parameterized testing. It allows running the same test with different sets of input parameters.
Nested Tests: JUnit 5 allows you to create nested test classes, which helps organize and structure your tests, especially when dealing with complex test scenarios.

import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.ValueSource
import org.junit.jupiter.api.Nested
import org.junit.jupiter.api.Test

class MathUtils {
  fun add(a: Int, b: Int): Int {
    return a + b

class MathUtilsTest {
  private val mathUtils = MathUtils()

  @ValueSource(ints = [1, 2, 3])
  fun `test addition with parameterized values`(value: Int) {
    val result = mathUtils.add(value, 5)
    assertEquals(value + 5, result)

  inner class NestedAdditionTests {
    fun `test addition with positive numbers`() {
      valval result = mathUtils.add(3, 5)
      assertEquals(8, result)

    fun `test addition with negative numbers`() {
      val result = mathUtils.add(-3, -5)
      assertEquals(-8, result)




In the example above, we have a MathUtils class that contains an add method. The MathUtilsTest class demonstrates the use of JUnit 5 parameterized tests with @ParameterizedTest and nested tests with @Nested annotations. The parameterized test runs the same test with different values, while the nested tests organize related tests within inner classes for better readability and maintainability.

Submit a Project With Zero Risk

Despite being one of the most popular languages, Kotlin app development is complex and requires great developers to get it right. Why take the risk of hiring anything but the best Kotlin developers?

DevTeam.Space is a community of field expert software developers experienced in the latest technologies. All of our dedicated Kotlin developers have been vetted and trained in our unique agile software development process.

We match only the most suitable developer or development team to your project specifications. If you would like to learn more, simply fill out our DevTeam.Space product specification form and one of our experienced account managers will get in touch to answer any questions you might have.


First you need to define your unique project requirements so you know the exact skills you will need in your Kotlin developer. Once you have done this, you will need to decide whether you want to go the cheap route and hire freelancers or outsource developers from a professional software development company. We advise the latter. Then you need to post your developer requirements and start interviewing. Note: The interview process is far less comprehensive when hiring from a software development company as they will have already vetted their developers.

DevTeam.Space allows companies to outsource its full-time developers as and when they need them. Clients can hire individual developers, dev teams or outsource their entire project development to DevTeam.Space who will then build the entire project for them. All DevTeam.Space developers are overseen by a dedicated account manager to help take the load off your project manager.

There are a number of good software development companies where you can hire Kotlin developers. However, if you want the best Kotlin developers then the best software development company is DevTeam.Space.

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