Kotlin Skills

What is Kotlin?

Kotlin is a statically typed multiplatform programming language that is 100% interoperable with Java and Android. It was designed to address some of the limitations of Java while maintaining seamless interoperability with Java code. In 2017, Kotlin was officially endorsed by Google as a first-class language for Android development, leading to a surge in its adoption in the Android development community.

Kotlin is known for its modern syntax, concise code structure, and extensive set of features, including null safety, extension functions, data classes, and coroutines. It runs on the Java Virtual Machine (JVM), making it compatible with existing Java libraries and frameworks, and it can also be compiled into JavaScript or native code for use in other environments.

Hired platform data named Kotlin as the second most requested skill for Mobile Engineers in 2023.

What to use Kotlin for

Kotlin’s versatility makes it suitable for a wide range of applications and use cases, such as:

Android app development 

Kotlin has become the preferred language for Android app development, offering developers a more concise and expressive alternative to Java. It seamlessly integrates with existing Android APIs and libraries, enabling developers to build robust and feature-rich Android applications with ease.

Server-side development

Kotlin can also be used for server-side development, thanks to frameworks like Ktor and Spring Boot. With Kotlin, developers can build scalable and high-performance backend services, RESTful APIs, and microservices, leveraging Kotlin’s modern syntax and powerful features.

Web development

Kotlin can be compiled to JavaScript, making it suitable for building frontend web applications and backend services using frameworks like React and Node.js. With Kotlin, developers can write frontend and backend code in the same language, improving code consistency and developer productivity.

Desktop development

Kotlin’s compatibility with Java Swing and JavaFX allows developers to build desktop applications using familiar tools and libraries. Kotlin’s modern syntax and features make desktop development more enjoyable and productive, whether it’s building standalone applications or enterprise software.

Multiplatform development

Kotlin Multiplatform allows developers to share code between different platforms, such as Android, iOS, web, and desktop, using a single codebase. This enables faster development cycles, code reuse, and maintenance, making Kotlin an attractive choice for cross-platform development.

Companies of all sizes use Hired to find engineers with Kotlin skills

What is a Kotlin developer?

A Kotlin developer is a skilled software engineer who specializes in using the Kotlin programming language to build a wide range of applications and systems. Beyond just writing code, a Kotlin developer is proficient in understanding Kotlin’s principles, designing elegant and maintainable architectures, and collaborating effectively with other team members.

Here’s what it means to be a Kotlin developer:

1. Proficiency in Kotlin: A Kotlin developer is fluent in the Kotlin programming language, including its syntax, features, and best practices. They understand Kotlin’s modern approach to programming and know how to leverage its features to write clean, concise, and efficient code.
2. Android development skills: Many Kotlin developers specialize in Android app development, with a deep understanding of Android APIs, frameworks, and development tools. They know how to build user-friendly and performant Android applications using Kotlin and Android Studio.
3. Backend development skills: Kotlin developers also have experience in backend development, using frameworks like Ktor, Spring Boot, and Micronaut to build scalable and reliable backend services and APIs. They understand concepts like RESTful architecture, database integration, and cloud deployment.
4. Frontend development skills: Some Kotlin developers are proficient in frontend development, using Kotlin/JS to build web applications and Kotlin/Native to build desktop and mobile applications. They have experience with frontend frameworks like React, Angular, and Vue.js and understand how to integrate Kotlin code with JavaScript and native code.
5. Problem-solving abilities: Kotlin developers are adept at solving complex problems and troubleshooting issues that arise during the development process, whether it’s optimizing performance, fixing bugs, or implementing new features. They understand software design patterns, algorithms, and data structures and know how to apply them effectively in Kotlin.

Most important Kotlin developer skills in 2024

Here are some of the most important skills for Kotlin developers in 2024:

1. Advanced Kotlin features: A deep understanding of Kotlin’s advanced features, such as coroutines, inline classes, sealed classes, and property delegation, is essential for building modern and maintainable applications in Kotlin.
2. Android Jetpack: Kotlin developers should be familiar with Android Jetpack, a set of libraries, tools, and architectural guidance provided by Google for building Android apps. They should understand components like ViewModel, LiveData, Room, and Navigation, and know how to use them effectively in Kotlin.
3. Kotlin Multiplatform: Kotlin developers should have experience with Kotlin Multiplatform, a technology that allows sharing code between different platforms, such as Android, iOS, web, and desktop. They should know how to structure multiplatform projects, share code between platforms, and handle platform-specific concerns.
4. Reactive programming: Kotlin developers should be proficient in reactive programming paradigms and libraries, such as RxJava, Kotlin Flow, and Reactor. They should understand concepts like streams, operators, and observers and know how to apply them to build responsive and scalable applications in Kotlin.
5. Test-driven development (TDD): Kotlin developers should be familiar with test-driven development (TDD) practices and tools, such as JUnit, Mockito, and KotlinTest. They should know how to write unit tests, integration tests, and end-to-end tests to ensure the reliability and maintainability of their code.

Kotlin resources

Check out our resources to continue sharpening your Kotlin skills.

Hired profiles help developers showcase their top tech skills

After passing Hired skills assessments, candidates have the chance to showcase their skills to employers. They can opt to present an ‘Assessments’ badge on their profile. Candidates may take various assessments including Programming Skills, Full Stack, Backend, Frontend, iOS, Android, Debugging, Dev Ops Generalist, and Dev Ops AWS.

Why should you hire Kotlin developers?

If you’re a talent acquisition professional or tech hiring manager seeking software engineers, consider a Kotlin developer to bring these key benefits to the table: 

• Productivity: Kotlin’s modern syntax, concise code structure, and powerful features enable developers to write code quickly and efficiently, reducing time-to-market and accelerating project delivery.
• Interoperability with Java: Kotlin’s seamless interoperability with Java allows developers to leverage existing Java codebases, libraries, and frameworks, making it easier to migrate existing projects to Kotlin or build new projects with Kotlin and Java together.
• Android development: Kotlin is the preferred language for Android app development, offering developers a more modern and enjoyable development experience compared to Java. By hiring Kotlin developers, you can build high-quality and feature-rich Android applications that delight users and drive business success.
• Cross-platform development: Kotlin’s support for multiplatform development enables developers to share code between different platforms, such as Android, iOS, web, and desktop, using a single codebase. By hiring Kotlin developers with multiplatform expertise, you can build cross-platform applications faster and more cost-effectively.
• Community support: Kotlin has a vibrant and supportive community of developers who contribute to open-source projects, share knowledge, and provide assistance through online forums, meetups, and conferences. By hiring Kotlin developers, you gain access to this community and the collective knowledge and expertise it offers

Assess tech candidates for Kotlin skills

Looking for candidates skilled in Kotlin? Technical assessments are a multi-pronged solution. They allow you to streamline the hiring process and reduce bias with tech skill-focused benchmarks. 

Hired Assessments offer a library of hundreds of questions and customizable challenges tailored to technical preferences. See how Mastercard and Axon used Hired Assessments to vet top candidates. 

Hired also provides coding challenges, which give employers exclusive access to candidates who pass custom technical assessments. Learn more about how to accelerate technical hiring with these challenges.