Hire Kotlin developers

Kotlin is a statically-typed programming language that runs on the Java Virtual Machine and also can be compiled to JavaScript source code.

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D.Y.
    Senior Mobile Developer
Mobile Developer - iOS/Android, VR/AR, React Native, Flutter

Looking to commit to a long term and challenging project requiring extensive programming skills in Mobile Application Development. I have a solid background in creating complex mobile applications for iOS/Android platforms and more, including implementing virtual and augmented reality using Unity and ARkit/ARcore frameworks.

Skills & Technicals Expertise:

  • Development of cross-platform hybrid and/or native mobile applications targeting iOS, Android and Mobile Web;
  • Object Oriented techniques, including common OO and web/mobile application design patterns;
  • Java, Objective-C and/or Swift, and in-depth knowledge of the iOS/Android SDK;
  • cross platform mobile development with ReactNative or Flutter;
  • AR/VR, Google Daydream, Google Cardboard, Oculus Rift, HTC Vive
  • Core Data, SQL Server, PostgreSQL, and other relational database programming and design;
  • jQuery, jQuery Mobile, Twitter Bootstrap, Angular, React and Knockout;
  • Geo-location/mapping/Postgres GIS/Web services (SOAP, REST);

Additionally:

  • Understanding of offline storage, threading, and performance tuning of mobile applications;
  • Push notification services;
  • Application/Web Servers: Tomcat; Jboss; Apache; LAMP ;
  • Cloud services: Amazon AWS (EC2, RDS, S3), Parse;

Passionate about the mobile marketing, have extensive knowledge about it and constantly develop my mobile programming career with strong desire to innovate.

  • USD 42.00 / hr
  • USD 5400.00 / mo.
  • Ukraine

A.A.
    Lead Architect
System Architect - Web & Mobile (Java / Javascript / Flutter / React Native)

15+ yrs of Software Development. Master of Science in IT (MSIT). Working for large Fin-tech corporations, various agencies, and startups. My strong points: Quality and Focus on the result. Looking for long-term collaboration

  • Programming languages: Java, Kotlin, ES6, Dart, Typescript, C/C++, Solidity
  • Fronted/Mobile: Flutter, Angular, RiotJS, React Native
  • Java: Hibernate, Apache Cayenne, Spring Data
  • Databases: PostgreSQL, MySQL, DB2
  • NoSQL: Google Firebase, MongoDB, Redis, Dynamodb, EJDB
  • Other: Ethereum, Spring Boot, Google Guice, Jenkins
  • Teaching the CS course: Java performance tuning at NSU

  • USD 65.00 / hr
  • USD 7700.00 / mo.
  • Russia

D.V.
    Lead Fullstack Developer
Lead/Senior Fullstack Developer

I have great experience in Software Engineering (over 11 years) and a great desire to make things better! Worked with different well-known companies (like Cisco, Spirent, Ezhome) on projects of different types, sizes, and complexity levels. Programming language polyglot. Keen to study new technologies and methodologies.

During my career time, I've never been encountered with the situation when something is undoable. Every approach has its own benefits and trade-offs but I'm 99.9%-sure that you can figure out what-why-when to choose in each situation. That's the main point, an impulse in my life that helps me to solve any issue that meets me on my way (not only in my career).

Mostly proficient in the following languages:

  • Javascript (from ES6 to babel:stage-0 + Typescript) (React, Redux, Flux, Apollo, GraphQL, Webpack and a lot more)
  • Java (Spring, Hibernate)
  • Golang
  • Python (Django, Celery)
  • Kotlin

  • USD 84.00 / hr
  • USD 10800.00 / mo.
  • Russia

N.Z.
    Lead Mobile Developer
Android / IOS Senior Mobile Developer / Architect

I'm a high-quality native iOS and Android apps wizard. I'm Oracle Certified Java developer with Master's degree in CS with 12 years of experience in developing not only Android and IOS projects, but also different projects that made me a great architect, complex issue solver and UX/Features improver in all aspects with experience in huge amount of libraries and frameworks such as Firebase, Parse, Spring and much much more. I'm the best in Android and iOS app development as I'm up to date with new technologies, features, and tricks that Google team or Apple team announce. I have led all projects from scratch up to release with a full understanding of OOP, SOLID, optimization, analysis and user experience. I'm proud of apps I made: GuruShots, LiftDay, LiveMaster, and others, so thanks to my clients that trusted me and gave me that opportunity. NOTE: Please do not be surprised by the large number of described technologies, that's even not all. 13 years is more than enough to be able to work with so many technologies!

  • JAVA: Android(all), JSE, JEE, Kotlin, Groovy.

  • Mobile: Android, IOS.

  • Swift 1/2/3/4: IOS 8/9/10/11.

  • Backend: Spring Boot, Grails/Groovy, XML, JSON, REST, XSL/XSLT.

  • DB: SQLite, Oracle, MySQL, DB2, PL/SQL, XMLDB, PostgreSQL.

  • Severs: Jetty, Tomcat, Apache, IBM Websphere, Parse server.

  • Libraries and Frameworks: Firebase, Gradle, Spring-Android, RoboSpice, Retrofit, ORMLite, Google Services SDK, iOS Extensions, Square libraries, CocoaPods, Parse SDK, Backendless, Layer SDK, AfNetworking, Alamofire, Hearst-DD/ObjectMapper, Facebook SDK, Twitter SDK, Instagram Kit, Flurry SDK, GoogleAppIndexing, Grails, Spring, Struts/Struts2, JPA, Jespa, Hibernate, Ant, Web Services, JMS, JUnit, pi4j(Raspberry Pi, Orange Pi), FFMPEG, DexProtector.

-Tools: Git, SVN, Intellij Idea, xCode 7/8/9, Android Studio, Jira, YouTrack, Zeplin.

-Methodologies: Scrum, Kanban.

  • Experienced in apps that included: Social, Chat, IM Messaging, Map, Filtering, Search, E-commerce, In-app billing/purchases, Store, Fitness, Photos, Event, Backup, Image, Contacts, Calendar, Share, Push, Interactive, Notifications Content/Service extension, Deep link, Navigation, Animation, Crop, File, Upload, JSON, REST, API, Library/Gallery, Paging, Storyboard, Support multiple screen sizes, Full stack, Best practice code, Convention, OOP, Play Store, Itunesconnect, TestFlight.

  • USD 52.00 / hr
  • USD 6600.00 / mo.
  • Russia

V.D.
    Senior Fullstack Developer
Fullstack Java developer | Kotlin | Node.js | Kafka | GraphQL | REST

I'm Full stack Java developer and system architect with significant technical and analytical skills. I have been team-leading for desktop, web and mobile application, backend and frontend development for corporative and individual clients in financial, fintech & IoT and other areas for the last 10 years.

BACKEND:

  • Java, Node.js, Multithreading, Spring, Spring IOC, Spring Security, Spring MVC, Kotlin, JPA (1,2), REST, Hibernate, Kundera, JMS, IBM MQ, WebServices, JDBC, JSP, AspectJ AOP, JavaMail, Ehcache, JUnit, Akka, Kafka, Struts 2, Vaadin, ActiveMQ, RabbitMQ, JAXB, Hazelcast, Vert.x, Hadoop, Ignite, Redis, GraphQL, Elasticsearch.

FRONTEND:

  • Javascript, AngularJS, Angular (2,4,5,6), Ionic, Knockout.js, jQuery, JS templates, HTML5+CSS, Twitter Bootstrap

DATABASES:

  • Oracle, MySQL, MSSQL ,DB2
  • NoSQL: Apache Cassandra

SECURITY:

  • Spring Security, JAAS, Apache Shiro

OTHERS:

  • Distributed interaction: Apache ZooKeeper
  • Data Processing: Akka, Apache Kafka, Apache Spark.
  • Full-text search: Solr
  • Version control: SVN, Mercurial, Git
  • Web frameworks: Spring MVC
  • Web/app. servers: Jetty, Tomcat, JBoss
  • Infrastructure: Docker
  • Build tools: Docker, Maven, Grunt, Yarn
  • Operating systems: Unix\Linux, Windows

I'm passionate about delivery software and not only writing code. My main focus is high-performance web applications are written in Java, relational and NoSQL databases, and web technologies. Followed both Agile and waterfall methodologies participated in all the project lifecycle stages – from requirements gathering till support and tuning in Production. Have a strong passion for a high-quality solution with good architecture.

  • USD 48.00 / hr
  • USD 6100.00 / mo.
  • Ukraine

A.N.
    Senior Mobile Developer
java/Kotlin developer

Experienced Java/Kotlin Developer.

Summary:

  • Over 8 years of software and webapps development;
  • Took part of lots of enterprise projects (portfolio with the selected products can be found below);
  • Fluent in Spring Boot and many related frameworks and technologies;
  • Striving for the SOLID design, but not forgetting about pragmatic approach;
  • High self-organization and discipline.

Technologies:

Java, Kotlin, Javascript, HTML, CSS, Sptring Boot, Spring Framework, RESTful services, Git, PostrgeSQL, MySQL, Hibernate, JPA, JUnit, TestNG, Mockito, Selenium Webdriver, Selenide, Jenkins, Bamboo, Azure DevOps, Docker, and many, many more.

  • USD 35.00 / hr
  • USD 5600.00 / mo.
  • Russia

M.C.
    Senior Mobile Developer
iPhone, iPad, Android solutions

I am a highly-qualified professional with a five-years experience in developing mobile applications for Android, iPhone, iPad. I have successfully launched over 50 projects in various domains and technologies, ranging from simple apps to complicated projects.

My main objective is a process-oriented approach that combines experience and creativity to find the most productive solutions and succeeding results. I am proficient enough in working in close collaborations with offshore clients as well. Flexibility and keeping ahead with technologies are my strengths, so I can guarantee the high quality of the work done.

Experience with iOS technologies:

  • Xcode, Objective-C
  • databases: CoreData( MagicalRecords including), SQLite
  • internet and server side interactions(AFNetworking library): REST API, SOAP, JSON, Parse, Google API
  • maps: iOS MapKit Framework, Google Maps API, Yandex SDK
  • social networks: Twitter API, Facebook SDK, VK SDK
  • storage: local storage, cloud storage (icloud, dropbox)
  • multimedia (photo, video, audio)
  • tools: Redmine, Git, SVN, SoapUI, DBMS (database management systems), Crashlytics
  • notification/reminders: Local Notifications / APNS,EventKitUI
  • in-app purchases
  • iAd

Experience with Android technologies:

  • Android studio, Java
  • Google Play Services and Patterns
  • Android libraries: Android Support Design Library, Android Support Library (v4, v7 appcompat, v7 cardview, v7 recyclerview), ActiveAndroid, RxJava, Retrofit, Picasso, UIL, ButterKnife, EventBus, Amazon
  • databases: Amazon DynamoDB, SQLite, Couchbase Lite Android
  • storage: local storage, cloud storage (Amazon S3, Couchbase Lite Android, dropbox)
  • multimedia (photo, video, audio)
  • tools: - Redmine, Git, SVN, SoapUI, DBMS (database management systems), Crashlytics
  • internet and server side interactions(AFNetworking library): REST API, SOAP, JSON, Parse, Local/Push-Notifications, Google API, GSON, GeoJson, Amazon SES
  • MVP
  • Google Android Maps Utils
  • in-app purchases

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Ukraine

M.T.
    Middle Mobile Developer
Full Mobile Development, iOS, Android, Cross-Platform (Flutter)

As an expert developer with 6+ years of experience in mobile application development, one of my most-respected qualities is the ability to find solutions to any problem. In addition, I am committed to open and ongoing communication with my clients, as this is key to every successful project.

All of my projects have contributed to the growth and development of my clients’ businesses and significant increases in their profits.

My expertise includes Blockchain Technologies, Client-Server Architectures and Application Publishing.

iOS Skills: Swift 5, Objective C, RxSwift, Alamofire, Eureka, Core Data, Realm, SwiftyJSON, SwiftLint.

Android Skills: Kotlin, Java, RxJava, Dagger2, ButterKnife, LiveData, DataBinding, Room, OKHttp, Retrofit, Volley.

My advantages: • World-class quality and experience • 24/7 support • Bug-free guarantee through comprehensive testing • Timely delivery • Scalable and clean architecture • 100% money-back guarantee

  • USD 35.00 / hr
  • USD 5600.00 / mo.
  • Russia

Y.S.
    Senior Mobile Developer
Expert Native iOS, Android developer/Augmented Reality (ARKit, ARCore)

Ambitious and results-oriented Mobile Application (iOS/Android) Developer with extensive knowledge, solid technical expertise and an “always get my job done” credo. Passionate about the mobile marketing and constantly striving to learn new technologies with strong desire to innovate.

Looking to get committed and make significant contributions into a large software development company that mainly focus on creating complex and challenging mobile application solutions.

Technical Skills & Expertise:

  • iPhone iOS SDK: UI, Fragments API, Location and Sensors API, SQLite, AsyncTask, Activity Lifecycle, Services, Maps, Material Design;

  • Object-Oriented design pattern and implementation in Swift and Objective C;

  • Cocoa/Cocoa Touch, Three20, Cocos2d, Sparrow, JDK, C Standard Library;

  • Geo-location/mapping/Postgres GIS

  • Web services (REST, SOAP);

  • Java Core: io, multi-threading, collections, generics, etc

  • Android SDK: activity lifecycle, fragments api, location and sensors, content providers, services, material design, etc

Crossplatform framework: Flutter

Databases: MySQL, SQLite

Cloud services: Amazon AWS (EC2, RDS, S3), Parse

Preferred workflow: Trello/Basecamp + Git + Slack

I am easy to communicate with and can work either independently or inside a team.

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Ukraine

R.G.
    Middle Mobile Developer
Android Developer with more then 2 years of commercial experience

A forward thinking developer offering more than two years of experience designing, implementing, integrating, testing and supporting Android applications for mobile and tablet devices on the Android platform.

Skills: Tools and Technologies: GraphQL, RxJava, Android SDK, Android Studio, Retrofit2, Glide, Gson, Dagger2, OSM, WebSockets, BLE, Hibernate, JPA, FlyWay, Coroutines Patterns: MVP, MVC, MVVM Languages: Java, Kotlin, C++ Frameworks: Spring, TensorFlow Data storing: MySQL, PostgreSQL, SQLite, Realm, Room Data languages: JSON, GraphQL APIs: Google APIs, Firebase, UploadCare, Youtube Soft Skills: Communications, teamwork, organization Miscellaneous: RESTful Web Services, HTML, CSS, Bootstrap

Highlights:

  • Created a lot of user-friendly, aesthetically pleasing and fully functional applications for Android
  • Proficient in object-oriented design, data structures, problem solving, complexity analysis, and debugging
  • Developing strong backend side which can be used for all mobile platforms
  • Have strong understanding of material guidelines, client - server architecture principles, mobile development life-cycle
  • Always using Android best practices and adding multiple screen dimensions support

My purpose is to help you realize your ideas and bring your vision to the mobile market. Also it involves building an app from scratch or updating existing apps, building strong restful apis, adding multiple screen support, etc.

  • USD 35.00 / hr
  • USD 5600.00 / mo.
  • Ukraine

A.M.
    Senior Mobile Developer
Android developer

Within 4 years I'm involved in Android development. One of my main skills is to create professional, responsive, intuitive mobile applications for Android.

I know how to create quality android apps. I am responsible and always in touch with my clients. These stories when a freelancer hasn't communicated with a customer for several days are not about me. Also, I complete tasks on time because I understand that it is important for you.

I am a responsible worker. I do my work with the full dedication and strive for excellent quality. From my side, I guarantee high-quality work while doing it as fast as possible. I am available to start work immediately and up to 40 hours per week.

Technical Skill Set:

  • Good understanding of Core Java, Kotlin concepts (oops, collections and multithreading)
  • Experience working with different versions of Android, and how to deal with different screen sizes
  • Familiarity with RESTful APIs to connect Android applications to back-end services (Retrofit, OkHttp, Websockets)
  • Experience with offline database storage (Sqlite, Realm)
  • Knowledge of the open-source Android ecosystem and the libraries available for common tasks. Android SDK (Fragment API, Bluetooth/BLE API, Camera API, Service API, BroadcastReceiver, Job Scheduler API)
  • Android Testing (Robolectric, Mockito, Espresso, UI Automator, Junit, Hamcrest)
  • Image processing (Picasso, Glide, Fresco)
  • Google Play Services (Maps/Places, Location, GCM, AdMob/DFP, Drive, Face Detection)
  • Firebase (Auth, Database, Notifications, Analytics, Cloud Functions, Crash Reporting etc.)
  • Social networks (Facebook SDK, Twitter SDK, Instagram SDK, Vkontakte SDK)
  • Proficient understanding of code versioning tools, such as Git
  • Strong knowledge of Android UI design principles, patterns, and best practices (Support libraries, Custom views, Custom themes/styles)
  • Ability to understand business requirements and translate them into technical requirements.

Looking forward to work with you!

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Belarus

A.S.
    Senior Mobile Developer
Senior Android Developer

I develop mobile apps since 2014, which you can see in the portfolio below.

My projects vary from GPS fitness tracking apps to accounting platforms, and also include popular titles like Los Angeles Film Festival client app.

I either use design assets from an in-house designer or create them myself using mobile design guidelines.

Usually, the collaboration starts with a video call, where we can discuss project details and their implementation, after which a client can request an estimate and receive daily updates about the progress.

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Ukraine

O.K.
    Senior Mobile Developer
iOS and Android native, Flash/Flex/AIR developer

I believe my strong points are responsibility and creativity. And this gives me an ability to make things done. Being working on project I think not only about code but also how it will look for the end-user and always do proposals how to improve the target applications. My main goal is always meet your needs and deadlines. I'm honest and fair. Since 2012, I was programmer for rich web and desktop application projects involving wide range or technologies such as video streaming and composing, rich client-server technologies. From the 2016 year started developing for iOS mobile. Thank you in advance for your time and consideration. I look forward to working with you soon. Listed below are my experience and skills. — iOS: Swift, Objective-C, CocoaTouch, XCode; — Core web: XML, JSON, HTML/CSS, JavaScript; — ActionScript3/Flex/AIR: Core, Sockets, AES-crypto, Stage3D, OSMF, Flexunit, etc; — Frameworks: JQuery, Bootstrap, AngularJS, Meteor, Away3D, GreenSock, Robotlegs, etc; — IDE: FlashBuilder, FlashDevelop, Eclipse, IDEA, XCode etc; — OS: Windows, MacOS; — VCS: Git, SVN; — Issue trackers: Jira, Redmine, Trello; — Other expertises: MySQL, SQLite, Firebase SDK, ffmpeg.

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Ukraine

O.H.
    Middle Mobile Developer
Quality-Focused iOS/Android Developer

I started out in IT as a QA specialist working on various web and mobile projects. Later on I learned and got hands on experience in Java and Objective-C. At first I use those primary for testing automation, but then I realized that I want to move forward and become a mobile developer.

During the years of my professional career I studied a lot about software quality and most common mistakes that developers usually do. This allows me to produce more accurate estimates for new similar tasks, and leverage my own solutions to make those best suited for end customers.

I have 2+ years of programming experience and took part in dozens of projects as a full stack mobile developer.

My tech stack includes:

  • Android development (Kotlin/Java)
  • iOS platform development (Swift/Objective-C)
  • creating cross-platform apps with Flutter
  • Cocoa/CocoaTouch, CoreData, UIKit, CoreAnimation, CoreGraphics, CoreLocation, Security framework, etc
  • Apple Watch apps, Augmented reality (ARKit/ARCore)
  • moderate experience in HTML5/CSS3, JavaScript
  • 3rd party services integration (RESTful, Websockets)
  • FireBase, Parse, AWS
  • Git, Trello, Asana, Jira, Slack, etc

  • USD 37.00 / hr
  • USD 5900.00 / mo.
  • Ukraine

K.B.
    Senior Mobile Developer
Mobile Developer | Web Developer | iOS Android | Full Stack

I’m an active 🍎🤖 Mobile, Web Developer, technical co-founder of 👾 Locorbi Team. I’m a motivated team leader and developer who won't quit work until it's done, and the client is satisfied.

My expert area is native Mobile development. I've been developing for iOS since iOS 7.0. Over the last four years, I’ve worked on different native iOS and Android apps including iBeacon, Bluetooth integration, OpenWebRTC, WebSocket and other cool technologies. I am a swift learner and so far have not come across any app that has stopped me.

Our Locorbi Team could realise any your ideas 💡and solutions 🧰

Skill set: ○ Native Mobile: 📱 ••• iOS (Swift, Objective-C); ••• Android (Java, Kotlin)

○ Web JS stack: 💻🚀 ••• React; ••• Redux; ••• Reselect, ••• Recompose ••• Next ••• Angular2+ ••• Ngrx; ••• Vue.js; ••• Underscore; ••• etc🙂;

○ Technologies: 🏰 ••• .Net; ••• Java(EE, Hybernite, Spring, Spark); ••• Node.js;

○ Device: 🕹 ••• Bluetooth Low Energy (BLE), iBeacon;

○ Graphic Designing: 🌆 ••• Sketch, Photoshop;

○ Database: 🗄 ••• Postgres, PostGIS​, MySQL, CoreData, ActiveRecord, Realm;

○ API's: 🐼 ••• Facebook API, Instagram API, Uber API;

○ Purchases: 💵 ••• In-App Purchase, Stripe;

○ Ads, Maps, Clouds, Testing & Crashes, Frameworks: 📰🗺⛅️🐞🎸 ••• iAd, AdMob; ••• Google Map, Apple Map; ••• Firebase, iCloud; ••• Flurry, Testflight, Crashlithics; ••• ReactiveCocoa, Vuforia, OpenWebRTC, AFNetworking, Alamofire, CoreLocation;

○ Git: 🌲 ••• Github, BitBucket, GitLab;

Experiences 💣: ○ Social Networking with Maps, Chat, Event, Comment, Media Sharing; ○ Bluetooth LE data synchronizing; ○ Augmented Reality with Vuforia; ○ Control Device via WebSocket​ and getting Video by OpenWebRTC Protocol (Ericsson); ○ Photo/Video Editing & Sharing with Social, Effect, Filter;

  • USD 40.00 / hr
  • USD 6400.00 / mo.
  • Ukraine

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