Hire Kotlin Developers: Top Tips to Find the Right Talent for Your Project in 2025

What is Kotlin?

Kotlin is an open-source technology used for the development of native Android or cross-platform mobile applications. Popular platforms like Pinterest, Netflix, Trello, and Coursera are created with Kotlin. This programming language was developed by JetBrains in 2011. This coding language was created with a focus on being interoperable with Java, allowing for seamless app development across different environments and ecosystems that support Java.

What is Kotlin used for?

Although Kotlin is the most used for the development of native Android applications, it is also adaptable for iOS, Linux, and JVM and cross-platform app creation. This language is 100% compatible with Java.

• Android app development: The primary role of Kotlin programming language is the development of applications for the Android ecosystem. The official IDE for Android development, Android Studio, fully integrates support for Kotlin, providing similar code completion and type-checking features seen in Java. Most companies need to have a mobile presence because the majority of individuals now use their mobile phones to access the internet. With Android holding more than 70% of the mobile phone market share, there is a high demand for Kotlin developers, even if Kotlin was solely used for Android development.
• Cross-platform app development: Since Kotlin is interoperable with Java, it is widely used for the development of cross-platform applications for iOS and Android operating systems. The benefit of multi-platform mobile apps is that they use a single code base for both environments, significantly reducing the development cost, timelines, and time to market.
• Back-end web development: Kotlin is used for server-side web development, significantly simplifying the processes. The language's contemporary aspects enable software engineers to create applications that can easily grow on standard hardware. Because Kotlin is compatible with Java, you have the option to transition an application to Kotlin gradually, switching one file at a time while the remaining part of the application continues to utilize Java.
• Kotlin for data science: Data scientists use standard Java libraries but create code using Kotlin. Jupyter and Zeppelin, which are commonly used by Data Scientists for data visualization and exploratory research, support Kotlin.

Why choose Kotlin for business app development

Now that you know what Kotlin is used for, it’s time to see what advantages it can bring to your business application.

• Smooth integration with Android Studio

Currently, Kotlin is seen as the main language for creating Android apps, with the Android OS providing support packages for it. Furthermore, Kotlin reduces the necessity for lengthy coding during app creation.

• Improved speed and efficiency

Kotlin greatly enhances application performance and provides a seamless user experience by utilizing advanced features and code optimizations to reduce runtime errors and improve overall code efficiency.

• Multi-platform compatibility

Kotlin and JavaScript work well together, enabling developers to create cross-platform solutions for various platforms. This implies that the identical Kotlin code can be utilized on multiple platforms like Android, iOS, and the web, without requiring significant modifications.

• Reduced development costs

Thanks to its cross-platform compatibility, Kotlin code can be written once and then reused to launch applications within different operating systems. This not only accelerates time-to-market but also significantly reduces the development costs compared to native app development.

• 100% interoperability with Java

Kotlin smoothly integrates with Java, enabling the insertion of Java code into Kotlin apps and vice versa with no issues. This indicates that developers can make use of the Java libraries, tools, and frameworks already available in Kotlin app development projects.

Check out our recent blog post to discover how custom application development can boost your business.

Where to find dedicated Korlin developers?

Since Google announced Kotlin to be its official language in 2017 and announced first-class support for it on Android, this technology gained a grand popularity, creating huge demand for Kotlin developers. Since then, there has been an increase of 1400% in Kotlin developer jobs.

With so many specialists available all over the world, it becomes challenging to find and hire truly skillful and experienced professionals and not amateurs who have the last word in technology trends. 3 ways of hiring Kotlin mobile app developers are:

1. Full-time in-house employee.
2. Freelance developer.
3. Outsource specialist.

Let’s stop each way in more detail.

In-house developer

Hiring a full-time in-house Kotlin development team is reliable but not always the most cost-effective option. To find candidates, you can explore local job boards, LinkedIn, tech community platforms, and more. Another approach is to post your job opening online and review incoming applications. However, this process can be time-consuming and involves significant investment in recruitment, HR processes, interviews, and other hiring activities.

Freelancer

A freelancer is an independent remote contractor who works on an hourly basis. You can find them on special freelance platforms like Upwork, Feever, and Freelancer. You can post your job offer there as well, enabling you to find specialists with the exact skills needed for your project. Freelance outsourcing might be a great option if you are looking to reduce costs. However, managing freelance workers requires additional management and communication resources and regular check-ins to ensure the work is completed within the deadline. In addition, freelance contractors may juggle multiple clients at once, affecting their availability and focus on specific projects.

Outstaffing developer

Outstaffing is a collaboration model that combines the benefits of an in-house team and the flexibility of outsourcing. When you decide to opt for outstaffing services, you need to search for an external Kotlin development services provider and hire dedicated developers from them. These specialists work remotely on your project but will perform as part of your internal team and follow your workflows and processes and participate in daily meetings or stand-ups as required. Outstaffing gives you full access over to the project implementation putting aside all the hassle connected to HR processes, taxes, perks, insurance, and others, as all of the above is handled by the outstaffing company.

Here at Drupfan, we understand the importance of providing seasoned Kotlin developers for businesses all over the globe. Minding your time zones, we have our hubs strategically located across Canada and Europe, providing both nearshore and offshore outsourcing services for customers worldwide. Hire our top-notch Kotlin developers for your next project!

Tips for Hiring the Best Kotlin Developers

Let’s review the most crucial thing you should do when looking for and hiring Kotlin developers for your app development project.

1. Thoroughly review resume: Analyze the candidate's resume closely to confirm their technical skills, pertinent experience, and project background in order to match the role's needs.
2. Assess dev’s knowledge on the interview: Evaluate the developer's grasp of necessary technologies and problem-solving skills by asking specific technical questions during the interview.
3. Ask to complete a test task: Give a brief test task or coding challenge that mirrors real-life situations to evaluate the applicant's practical skills and problem-solving approach.
4. Ensure technology fit: Make sure the developer has the necessary skills to work with your tech stack by checking if they are familiar with the tools, languages, and frameworks used in your projects. When hiring a Kotlin developer, check the following expertise: Kotlin, Java, Android development, proficiency in Git, familiarity with Gradl or Maven building tools, knowledge of databases (like SQL), understanding how to consume and create RESTful services or GraphQL APIs, experience with CI/CD Tools, and work with cloud services (like AWS).
5. Gather feedback and testimonials: Ask for references or feedback from former employers or clients to confirm the developer's performance, dependability, and contributions in previous positions.
6. Assess soft skills: Evaluate the developer's communication, teamwork, and adaptability in the interview to assess their soft skills, which are essential for effective collaboration within your team.

Top questions to interview Kotlin developer

When interviewing a Kotlin app developer, ask these questions to check his expertise and knowledge:

1. How does Kotlin interact with Java?
2. What benefits does Kotlin offer in comparison to Java?
3. Explain the fundamental syntax variances between Kotlin and Java.
4. Describe the notion of null safety in Kotlin.
5. Specifying variables and constants in Kotlin is essential.
6. Describe the concept of string interpolation in Kotlin.
7. What do range expressions in Kotlin include?
8. Explain Kotlin's approach to managing control flow statements.
9. Explain the concept of functions in Kotlin.
10. What is the representation of lambdas in Kotlin?
11. Provide an explanation of function references in Kotlin.
12. Talk about classes and objects in Kotlin.
13. What does Kotlin define as a primary constructor?
14. Describe the idea of companion objects in Kotlin.
15. What mechanisms does Kotlin provide for performing filtering and mapping tasks on collections?
16. Examine how Kotlin handles the sorting of collections.
17. What does CoroutineScope represent in Kotlin?
18. What do threads represent in Kotlin?
19. Explore Kotlin's strategy for avoiding deadlock.
20. What do checked and unchecked exceptions represent in Kotlin?

Of course, this is only a small part of the questions to check the expertise of a Kotlin developer and can be adjusted based on your project’s focus. In general, these questions cover a wide range of topics and provide a thorough evaluation of a Kotlin developer's abilities and expertise. You could also think about including situation-based or hands-on coding questions to better assess their problem-solving abilities in real-life situations.

Average Salary of Kotlin developers around the world

The hourly rate of Kotlin app developers depends on their level of expertise and location. Below, we review the average salary of middle Kotlin specialists.