Hire Expert Kotlin Developers

Are you looking to hire expert Kotlin developers?

This article will answer all the most interesting questions about hiring expert Kotlin engineers, programmers, or development teams.

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

This powerful open-source language grew steadily after its launch 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.

In this article

1. Primary Kotlin development skills
2. Other software development skills for Kotlin developers
3. How to find the best Kotlin developer?
4. Interview tips to hire Kotlin developers
5. Examples of coding questions to ask during the interview when hiring Kotlin application developers

Kotlin's many advantages are why it is so highly sought-after among the most important programming languages for Android, the world's most targeted mobile OS. To start with, Kotlin supports both object-oriented and functional programming. It’s fully interoperable with Java. It targets the 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. The language has a vibrant developer community and a bright future.

It is not surprising, then, that lots of mobile app 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 will dramatically improve your chances of success when undertaking complex projects.

Before hiring Kotlin developers, you must understand your desired skill requirements. Since your requirements will be unique to your project, we can only provide a general idea of the exact skills that you need. If you need more help, get in touch.

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 knowledge of object-oriented programming (OOP);
• Good knowledge 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 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, and Factory helps write 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 for Kotlin developers

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, as most industries are highly regulated, and your application must comply with these regulations. If you plan to target these industries with your app, application security becomes critical.

You can use various security approaches; however, hiring Kotlin app developers with the right skills for your project is vital. Look for Kotlin programmers who know how to use the security features of Kotlin effectively and can tell you how they would secure your app.

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

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

• Secure Authentication (2FA - Two-Factor Authentication) Secure authentication is essential in ensuring 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, thereby reducing the risk of security vulnerabilities.

Implementing these safeguards during 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 who can review Kotlin code written by other developers. Code review is important since it enables you to detect defects early in the development 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, or can even outsource them specifically to review their code. Get in touch if you need help.

C. Good communication and team skills

Nowadays, it’s impossible to build a great product with just one developer, so Kotlin engineers 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. Good 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 essential for this.
• Passion for excellence Since the mobile application market is competitive, you need to offer your users the best app. Developers must be dedicated to such excellence.
• 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. To reiterate a point we made earlier, you will only be able to define the exact skills that you need from your developers by reviewing your project requirements.

Once you have done this, take the following steps to hire Kotlin app developers:

1. Which 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, 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 who can give your project the required dedication. 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 your freelancers leave your project mid-way? You need to hire replacement developers, and that’s entirely your headache. Worse still, what if they steal your code?

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.

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

Companies like ours provide highly skilled, experienced, and motivated web and mobile app 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, and all of our developers work for our platform on a full-time basis.

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

2. Interview the shortlisted candidates

Ok, so you have initiated the hiring process. Several developers have sent you their resumes. You now 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 to 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 will work full-time with the company.

Go beyond general theoretical Kotlin expertise. Look for candidates who 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 we advise having an expert on hand who can really grill them on their answers. This will help you get the best developers.

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 from the outset. Effective onboarding is key to high levels of productivity.

Explain your business needs and project requirements to your 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 throughout the project.

Interview tips for hiring Kotlin developers

We offer the following tips for hiring Kotlin app developers:

A. Look for Kotlin app developers who know the essential features of the language

You can implement many functionalities in Kotlin by writing less source code than in other languages. The same code in an older language can’t achieve the same functionality.

You should look for developers who know about Kotlin's essential capabilities. Don’t expect Kotlin programmers to know every obscure feature the language offers, but they should know libraries such as SKL, Room, Retrofit, Glide, Anko, and Koin. Android Jetpack and ViewBinding expertise are 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.

Top Tip: Quiz your candidates on the technologies you will need to use in your project. Start by asking them to recommend solutions before quizzing them deeper on each one to find out why they are suitable.

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 suit as many different project requirements as possible. For example, typical offerings include fixed prices, time and materials, 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. Review their past projects carefully and read as much feedback as possible from sites like Clutch, etc.

You can see DevTeam.Space's reviews on Clutch here.

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

You get access to a vast 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 more complicated. A capable and experienced team leader with experience managing a remote work team can help, though. Such a team leader reduces management overheads. Look for an innovative team leader when hiring remote teams.

Note: Companies like DevTeam.Space assigns experienced account managers with technical expertise and have previously managed similar projects. Your dedicated account manager will help your project manager in any way they need while also closely monitoring the performance of our 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.

Answer 

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 the awaitAll function. The async builder starts a new coroutine for each network request, and awaitAll suspends the coroutine until all requests are completed.

<i>kotlin</i>
<i>import kotlinx.coroutines.async;</i>
<i>import kotlinx.coroutines.awaitAll;</i>
<i>import kotlinx.coroutines.runBlocking;</i>
<i>fun main() {</i>
 <i>runBlocking {</i>
 <i>val request1 = async { makeNetworkRequest("https://api.example.com/data1") }</i>
 <i>val request2 = async { makeNetworkRequest("https://api.example.com/data2") }</i>
 <i>val request3 = async { makeNetworkRequest("https://api.example.com/data3") }</i>
 <i>val results = awaitAll(request1, request2, request3)</i>
 <i>println(results)</i>
 <i>}</i>
<i>}</i>
<i>suspend fun makeNetworkRequest(url: String): String {</i>
 <i>// Simulate network delay</i>
 <i>kotlinx.coroutines.delay(1000)</i>
 <i>// Perform the network request and return the result</i>
 <i>return "Result from $url"</i>
<i>}</i>

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?

Answer

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 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.

Answer 

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.

<i>kotlin</i>
<i>import org.junit.jupiter.api.Assertions.assertEquals</i>
<i>import org.junit.jupiter.params.ParameterizedTest</i>
<i>import org.junit.jupiter.params.provider.ValueSource</i>
<i>import org.junit.jupiter.api.Nested</i>
<i>import org.junit.jupiter.api.Test</i>
<i>class MathUtils {</i>
 <i>fun add(a: Int, b: Int): Int {</i>
 <i>return a + b</i>
 <i>}</i>
<i>}</i>
<i>class MathUtilsTest {</i>
 <i>private val mathUtils = MathUtils()</i>
 <i>@ParameterizedTest</i>
 <i>@ValueSource(ints = [1, 2, 3])</i>
 <i>fun `test addition with parameterized values`(value: Int) {</i>
 <i>val result = mathUtils.add(value, 5)</i>
 <i>assertEquals(value + 5, result)</i>
 <i>}</i>
 <i>@Nested</i>
 <i>inner class NestedAdditionTests {</i>
 <i>@Test</i>
 <i>fun `test addition with positive numbers`() {</i>
 <i>valval result = mathUtils.add(3, 5)</i>
 <i>assertEquals(8, result)</i>
 <i>}</i>
 <i>@Test</i>
 <i>fun `test addition with negative numbers`() {</i>
 <i>val result = mathUtils.add(-3, -5)</i>
 <i>assertEquals(-8, result)</i>
 <i>}</i>
 <i>}</i>
<i>}</i>
<i>}</i>
 <i>@Nested</i>
 <i>}</i>
 <i>}</i>
<i>}</i>

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 Kotlin 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.

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