Hiring Kotlin Developers | A Simple Guide

by | Jul 28, 2023 | Tips & How-To's | 0 comments

Photo by Elijah Mears on Unsplash

The following is a compact guide that covers what we consider to be the most important points about hiring Kotlin developers. Whether you are a fast growing startup or a stable SME, with this guide you will be a step further in being able to hire the right candidate.


Let’s dive right in!


What is Kotlin?

Kotlin, a modern, open-source, cross-platform programming language released in 2016, offers numerous features that make it widely accessible and appealing to developers.

Being open-source and cross-platform, Kotlin provides developers the flexibility to work on any major platform, including Windows, Linux, or Mac. Its open-source licensing also allows for easy modification of the project.

Features of the Kotlin programming language

Noteworthy features of Kotlin include static typing and type inference, both contributing to its status as a strongly typed language. Static typing performs type checking at compile time, detecting errors early in development. Type inference automatically detects data types at compile time, reducing the need for explicit type declarations.

Furthermore, Kotlin’s intentional interoperability with Java makes it compatible with existing Java codebases. Developers can seamlessly integrate Kotlin into Java projects and vice versa.

Kotlin’s compatibility with the Java Virtual Machine (JVM) has solidified its position in mobile app development, particularly for Android applications. With Kotlin now favored over Java for Android development, its popularity in the mobile app development community continues to grow.

|đź’ˇKey Differences between Software Developers – Junior/Middle/Senior & Lead 

Kotlin use cases today


Kotlin, which is mostly used for Android app development, has many applications in other areas as well:


  • server-side development: Kotlin complements Java for back-end web app development and supports Java class libraries.

  • data science: Kotlin is valuable for data pipelines and machine learning models supported by tools like Jupyter and Zeppelin.


  • multiplatform mobile development: Kotlin is used not only for Android, but also for iOS, watchOS, and Linux platforms.


  • full-stack web development: translating Kotlin to JavaScript allows the same code to be used on the front-end and back-end.




What began in 2017 as an alternative to Java, set forward in 2019. The Google company announced the next big step: : Kotin first. Android development will increasingly be based on Kotlin. Many new Jetpack APIs and features will be offered in Kotlin first. This meant nothing other than:  When a new project is started, it should be written in Kotlin. According to google, “Code written in Kotlin often means a lot less code for you – less code to type, test, and maintain.”




The Meta Group uses over 10 million lines of code written in Kotlin in its Android codebase. The details about the switch from Java to Kotlin and the experience of the developers as well as the corporation with this migration are presented in its development blog. The switch appears to be a complete success for both the developers and the group as a whole. That means Facebook, Instagram, instant messaging apps like WhatsApp and Facebook Messenger are now largely based on Kotlin and Java.


|đź’ˇGuide for Scaling your Tech Startup Successfully in 2023


What Kotlin brings your project


Benefits of Kotlin:


  • Interoperability: Kotlin works seamlessly with Java, making it easy to migrate Java applications. It can be compiled into JavaScript or an LLVM encoder, which ensures smooth code integration with other programs.


  • Security: Kotlin includes null security features to prevent common programming errors such as null pointer exceptions, increasing code reliability and security.


  • Community support: Although Kotlin is a newer language compared to Java, there is a growing community of developers dedicated to improving the language and providing valuable documentation


  • Tooling support: Kotlin enjoys excellent Android tooling support, including Android Studio, Android KTX, and Android SDK, making it an optimal choice for Android development.


  • Clearness: by eliminating redundancies in base syntax, Kotlin provides more concise code that saves developers time and increases productivity.


|đź’ˇHow to hire tech talent in 2023 | A brief guide

Project requirements

Being clear about your own project requirements is sometimes not as obvious as it sounds! To make the search for a Kotlin developer as effective as possible, you should be very clear beforehand what the project requirements are, what the developer should and must accomplish, and what the details are: Project timeframe, cost, etc.  

Then it is easier to search for a Kotlin developer, look for specific qualities and skills that fit your project requirements, determine a from-to limit in which the qualities of your developer can lie.

To create a working project plan, we have a guide for you: here


|đź’ˇThe Role of AI in a Tech Company

Talent search

Internal sources

  • check employers for kotlin knowledge 
  • training of employees

External sources

Matchmaking service

A matchmaking service company like codecombinator, offers a comprehensive two-level matchmaking process to ensure the alignment of tech stack and talent for your product. Our approach facilitates collaborative work environments within developer hubs, enabling seamless collaboration among your tech talent, embedded teams, and peers.

Key Features:

  • Two-Level Matchmaking: We match developers based on both the hub’s requirements and the specific tech talent needed, ensuring the best fit.

  • Flat Fee Model: Our pricing covers fringe benefits, office space, and equipment costs at the hubs, providing cost-effective solutions.

  • Global Talent Pool: Benefit from our extensive worldwide network of developer hubs, accessing a diverse pool of skilled professionals.

Moreover, our pricing is significantly more competitive, charging up to 40% less than equivalent domestic talent.



Developer-on-demand agencies offer access to a database of skilled candidates, allowing swift candidate selection. However, it can be challenging to identify high-quality providers and ensure alignment of the tech stack from the start.

Freelancer Marketplaces 

While these marketplaces offer quality services, freelancers may leave for more lucrative projects, leading to time-consuming onboarding processes and reduced output. Additionally, the added fees on these platforms can be costly, impacting the freelancer’s profit margin.


|đź’ˇThe Right Guide for your Software Development Project in 2023

Screening and selection process

Screening process

What’s essential to you aka. must have requirements:

These are critical criteria that candidates must meet, such as having legal work authorization in the country where the role is located or possessing basic coding skills for a website backend position.

Preferred or additional qualifications:

Set up the basic requirements to identify qualitative attributes that could enhance the candidate’s suitability for the role. Other additional qualifications strengthen the candidate’s profile, enabling them to excel in the position. For instance, prior experience in the same industry would be a valuable advantage for a good candidate. 

Interview your Kotlin Developer

Hard skills

The developer’s proficiency in the following areas is essential:

  • Syntax and Structure: Understanding the unique syntax and structure of Kotlin is vital. Differentiating Kotlin from Java is essential to ensure code is written appropriately for each language.

  • Programming Fundamentals: Mobile development requires adherence to programming fundamentals, such as code reuse, the single responsibility principle, and reusable classes.

  • Kotlin Features: Being proficient in Kotlin’s powerful and expressive features, like handling null safety and type systems, is essential.

  • Writing Stand-Alone Functions and Classes: The ability to write independent functions and classes is important for creating modular and maintainable code.

  • Deep Understanding of Kotlin’s Type System: Demonstrating a thorough understanding of Kotlin’s type system ensures accurate and efficient coding.

  • Proper Use of Variables and Data Types: Skillfully using variables and data types to achieve desired results is a crucial aspect of Kotlin development.

  • Utilization of Kotlin Extension Functions: Proficiency in knowing when and how to use Kotlin extension functions enhances code readability and reusability.

Other areas of interest:

  • Knowledge of the Android Jetpack libraries

  • Experience with Android Studio

  • Knowledge of how to create, package, and sign an app

  • Compliance with industry standard architectural patterns

Soft skills

We name them in the majority of our posts, simply because these are so important:

  • Effective Communication: the ability to communicate clearly and concisely is critical to interacting with the team, customers, and stakeholders and ensures successful message delivery.

  • Problem Solving Skills: good problem solving skills are essential for programmers. Finding solutions independently, including using resources such as Stack Overflow, adds value to the development process.

  • Ability to collaborate: successful teamwork fosters a conducive environment for delivering quality work and achieving common goals.

  • Paying attention to detail: carefully identifying and fixing bugs while maintaining clean and well-documented code is of utmost importance.


Interview questions 

Here are some interview questions you could ask your Kotlin Developer during the interview:

  • What makes Kotlin so strong as a language?
  • Define Kotlin and its significance as a programming language

  • Kotlin’s role in Android development
  • Describe how Kotlin is used in Android app development and its benefits

  • Reasons for switching to Kotlin from Java
  • Explore the motivations behind adopting Kotlin over Java and the appeal to developers

  • Primary constructor in Kotlin
  • Explain the concept of a primary constructor in Kotlin and its usage

  • Understanding Null safety in Kotlin
  • Elaborate on Null safety in Kotlin, ensuring variables are protected from null values

  • Data class in Kotlin
  • Define what a data class is in Kotlin and its purpose in simplifying data modeling

  • Difference between var and val in variable declaration
  • Explain the distinction between using ‘var’ and ‘val’ when declaring variables in Kotlin

Average salary of a Kotlin Developer

According to the data of Glassdoor.com the average salary is around $96k p.a. with extra payments included (bonus and profit sharing options). Without that it is around $89k.  

Image of the average salary of Kotlin Developers: According to the data of Glassdoor.com the average salary is around $96k p.a. with extra payments included (bonus and profit sharing options). Without that it is around $89k.

Spare yourself the additional costs like office costs and other expenses while choosing codecombinator. Our Kotlin Developers are already employed, utilities are covered by our hubs. 


|đź’ˇHow to use the current Crises as an Opportunity for your Startup Growth

Hiring Guides for the top programming languages

We also have hiring guides for different programming languages, maybe the one you are looking for as well can be found here.


Do you have any other questions about our service? Please see our FAQ to get a quick answer. 

Follow us on social media