Hire Top Kotlin developers with Ultragenius

Ultragenius is a marketplace for top software developers, engineers, programmers, coders, architects, and consultants. Top start-ups and companies choose developers from Ultragenius platform for their critical software projects. Hire from Ultragenius network & scale your engineering team in a matter of few days. 

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Kotlin developer

Rishabh is a software engineer having 7+ years of experience developing Android and server-side applications using Kotlin.

Expert in






10 Years


Full Time


Kotlin developer

Mahesh is a software engineer having 3+ years of experience in developing multi-platform mobile applications using Kotlin and Java.

Expert in






10 Years


Full Time


Part-time Kotlin developers

John is a software engineer having 10+ years of experience developing modern Android, front-end web applications using Kotlin and Javascript.

Expert in






10 Years


Full Time

Hire top talented Kotlin developers with Ultragenius

Kotlin is a robust, cross-platform, statically typed, general purpose programming language designed initially for Java Virtual Machine (JVM), but is now used for web development, web front-end, Android, and multi-mobile platforms. Kotlin is a “pragmatic”  language which integrates the features of object-oriented programming with functional programming. The applications developed using Kotlin are lightweight, faster in compilation, and do not increase in size. Any part of code written in Kotlin is much smaller in size as compared to Java. Kotlin makes the code less verbose as compared to Java.

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Want to hire Kotlin developers on your own? Here are the skills you must look for while hiring a Kotlin developer

Hiring Kotlin developers might be a complicated task for you if you are a non-technical manager. Kotlin is one of the most demanding programming languages of today’s growing IT sector. Kotlin first developed for Android application development, now also used for front-end web development, server-side web applications development, and more. Kotlin supports cross-platform compatibility and combines the characteristics of object-oriented programming with functional programming. But, hiring the Kotlin developers among thousands of Kotlin developers is a challenging task for anyone even when one is an expertise in technical field. So, Ultragenius is here to assist you while hiring the top talented developers on your own. 

The following skills you must ensure while hiring a Kotlin developer – 

Knowledge of Android Software Development Kit

Android Software Development Kit (SDK) consists of tools and libraries required for Android application development. Since Kotlin is majorly used in Android application development field and can be easily integrated with Android Studio, the Kotlin developer must know about the debugger, gradle, emulator, Android OS, and several Android libraires which is provided by Android SDK.  

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Proficient using Android User Interface Layout

Kotlin developers must be proficient in using User Interface. Check if the Kotlin developer considers cross-device compatibility while developing an Android application. If your application is functioning well but lacks the usage of modern UIs then it won’t be used by your customers in the long run. The Android developers must know about  – 

  • Constraint Layout – It is used to design complex layouts, use appropriate menus, use vector drawables in place of raster graphics apply various kinds of animations to enhance user experience.
  • Linear Layout – It is the most basic layout that arranges the program elements either vertically or horizontally.
  • Relative Layout – Relative Layout is used to eliminate the use of nested view groups and keep the view hierarchy clear. Instead of using multiple Linear Layouts, you can replace them all with a single Relative Layout.
  • Frame Layout – Frame Layout is used to display a single item on the screen by blocking out an area. 
  • Grid Layout  – Grid Layout lays out views in a series of multiple rows and columns. Grid Layout is very flexible and can be used to design simpler layouts and remove or reduce the complex nesting which is required to design beautiful, catchy UIs.

Knowledge of mobile app architecture and design

Mobile app architecture represents a mobile application’s presentation logic and defines how the app will look in the users’ hand.Mobile app architecture helps Kotlin developers design a most appropriate mobile application by defining specific set of rules about designing a mobile app, its design patterns and techniques to build well-structured mobile apps. The knowledge of mobile app design reduces the risk involved with the mobile applciation development. 

Familiarity with Kotlin syntax and ability to write code

The Kotlin developer should be able to code in Kotlin. The Kotlin developer you are hiring must know about the Kotlin variables, data-types, and functions, where to use immutable and mutable variables. The programmer must know about getter and setter methods, Spinner and Dynamic Spinner, Kotlin Array, String, Functions, Default and Named argument, Recursion, and Tail Recursion in Kotlin. 

Experienced working with code versioning tools like Git, SVN, TFS

Kotlin developers need to know how to use version control systems, like Git, SVN, TFS or Mercurial. They mostly use Git for their work as it helps the team in cooperating and organizing your code. It also assists with reviewing old codes and comparing them with new ones. Along with this a Kotlin developer must know how to make changes on the repository; add commits when necessary; push commits into other repositories if necessary; pull latest commit from another repository onto theirs. 

Additionally they should understand branching which allows developers of different fields (e.g., business logic) can work independently without any interference at all time since these branches are separate from one another until its needed (merging).

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Knowledge of Android architecture

Android consists of a stack of software components which is categorized into four main layers and  five different sub-sections –

  • Android Runtime
  • Applications
  • Application Framework 
  • Libraries
  • Linux Kernel
  • Android Runtime – Android Runtime is used for compiling bytecode into native instructions that are executed later by the device’s runtime environment. It provides the core component Dalvik Virtual Machine, which is a type of Java Virtual Machine that runs apps and android devicesDalvik VM makes every Android application run on its own and executes files in .dex format.
  • Applications – Applications are placed at the top layer in Android architecture. The Kotlin developer writes the application and installs it on the Applications layer. For example, Phone, Contacts, Books, Calendar, and other services, each having a different role in the overall application development.
  • Application Framework – Application Framework layer comes up with high-level services such as package manager, resource manager, views system, windows manager, and many more. The Kotlin developers use these services while designing an Android application.
  • Android Libraries – Android Jetpack, Square/Moshi, Retrofit, Room, Dager, ButterKnife, MyLittleCanvas, and many more libraries in Android help Kotlin developers to run the code smoothly.
  • Linux Kernel – Linux Kernel provides the architectural model for Android that handles the core functionality like memory management, multi-threading, security, and networking.

Familiarity with eXtensible Markup Language

XML stands for eXtensible Markup Language which is used to design formats for data which is used to encode documentation information, information about database records and transactions, and many more. A Kotlin developer must know about XML, which is used to design layouts in Android. Kotlin developers must know about different types of layouts such as LinearLayout, Relative Layout, Table Layout, Frame Layout, Text View, List View, and Grid View. The XML layout file is linked with the main business logic file written in Java/Kotlin.

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Knowledge of REST APIs for backend services

Application Programming Interface (API) is a set of programs which establishes communication between an end-user and applications. When an end-user requests some data, the APIs act as an intermediary that execute instructions and get the data from the server and take the response back to the client or end-user. Representation State Transfer APIs provide a great flexibility for handling multiple types of calls, returning different data formats, and can even change their structure with the correct hypermedia implementation. The Kotlin developers must be aware of these popularly used APIs – Gmail API, Google Analytics API, Google Maps, Weather App API, Kinvey, AppAccelerator, and many more.

Firm understanding of State Management

State Management is a technique of handling knowledge about a mobile application’s inputs across various related data flows. It provides the developers knowledge of where exactly is application’s data at a given point of time. With the help of state management, the developer can store a mobile app’s state until the user session ends. It centralizes and makes the code maintenance very easy, thereby streamlining Android app development process.

Knowledge of Android app lifecycle

The lifecycle of an app is the amount of time it acts in the system from creating it to destroying it is called the lifecycle of that application. There are total six callbacks to navigate between states of an activity in Android –

  • onCreate()
  • onStart()
  • onResume()
  • onPause()
  • onStop()
  • onDestroy(). 

The Kotlin developers must know how to manage lifecycles with lifecycle-aware components and saving UI states. 

Good grasp on Functional Programming concepts

Kotlin combines functional programming with object-oriented programming for development. Functional programming is a paradigm of building software by composing pure functions without mutating state and data. Functional Programming enhances the productivity of the program. It provides immutable data structures that are not faced with race conditions and  thereby employs safe multi-threading. Functional programming comes under the “Declarative Paradigm” in which the program logic is written without explicitly describing the flow control.

Knowledge of Object Oriented Programming concepts

Kotlin is used in-place of Java for developing Android applications.  Therefore, the Kotlin developer must know about the four pillars of OOPS including Encapsulation, Inheritance, Abstraction, and Polymorphism.
Encapsulation – Encapsulation bundles the data along with member functions that operate on the data. It binds the data into a single unit.
Inheritance – Inheritance is the mechanism by which a class can extend the functionality of another class. Inheritance gives the Kotlin developer an advantage to reuse the same code.
Abstraction – Abstraction enables data-hiding by showing the user only the necessary details and hiding the implementation details. 
Polymorphism –
Polymorphism is the ability of a function to take many forms. Polymorphism is of two types – Compile-time Polymorphism and Run-time Polymorphism. In Compile-time Polymorphism, the invoking method is decided by the type or number of arguments if there are multiple methods present with the same name. Run-time Polymorphism is achieved through Method Overriding. The child class provides the specific implementation of the parent class and the method invoked is decided at the run-time.

Bottom Navigation Bar in Android

Android Jetpack library provides the Navigation component which lets Android developers  use navigation from designing button clicks to complex patterns. Navigation is extremely important to know for Kotlin developers because it allows the users to navigate across the different pages of your application. Users might want to share data to some other application, navigate back-and-forth across the application, or launch completely a new activity. These actions can be implemented using Intents in AndroidCheck the developers’ knowledge about Implicit and Explicit intents. The basic application bar is Toolbar, which helps developers add menu icons, a popup menu, and a navigation drawer iconAnother is BottomNavigationView, whthe developer ch allows ato switch between various fragments in the same activity.

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Problem-Solving Mindset with strong communication skills

The Kotlin developer must have a strong problem solving skill because it helps developers to utilize existing solutions for the projects more efficiently, thinking abstractly, and enables them to write pseudocode for their project. The developer must know how to debug the code as well. Also, check if the Kotlin developer is able to write clean and concise code and can fluently communicate with other team members while explaining the code.

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Kotlin is a “pragmatic” language which integrates the features of object-oriented programming with functional programming. The applications developed using Kotlin are lightweight, faster in compilation, and do not increase in size. Any part of code written in Kotlin is much smaller in size as compared to Java. Kotlin makes the code less verbose as compared to Java. But hiring the best Kotlin developers is not an easy task when a large no. of Kotlin developers are competing to grab the job opportunities. 

Top Interview Questions to ask while hiring a Kotlin developer

Frequently Asked Questions

Ultragenius is one of the leading platforms for hiring remote talent and connecting developer and part-time developers with Silicon Valley businesses. We focus on finding the best talents who will perform extremely well and will be easily integrated into your teams. We filter out only the top 1% most skilled developers among the 20K+ developers who have applied on our platform. Candidates have to prove their self-reported experience by giving Ultragenius’ s skill tests.

Ultragenius first tests the developer’s skill set by conducting a two and half hour hiring test. Our hiring test judges a candidate on all aspects like aptitude, case study analysis, verbal and reasoning, coding questions based on data structures and algorithms, software engineering, system design, and more. Then, there is another round for the candidates who are selected from this round called “Higher-level Assessment Skill Test”, which is a video round that deeply analyzes developers’ major skills and asks questions about the projects they have worked upon.

Fill up the form which is on every hiring developer’s page and we will inform you once we select the top 1% Kotlin developers matching your job requirements.  After analyzing the candidates based on their resumes and two assessment tests, we provide you the feedback quickly. And if the developers selected by our team are fit for your job role, then we also provide the onboarding.

Ultragenius offers you only the most skilled developers who are top 1% among the 20K+ developers who have applied on our platform. After a rigorous selection and testing process, we sort out only the top candidates for you. You can check out Ultragenius’ s selection process for hiring Kotlin developers on https://www.ultragenius.club/hire-kotlin-freelancer/.

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