Juraj Kusnier, Android Developer in Munich, Bavaria, Germany
Juraj Kusnier

Android Developer in Munich, Bavaria, Germany

Member since November 9, 2022
Juraj is an experienced senior software engineer and Android app developer focusing on products and a high-quality user experience. In the last 10+ years, he worked on critical projects for small and large clients, banks, and government agencies and shipped apps for tens of millions of users. Juraj knows how to deal with large legacy systems and quickly and effectively set up and launch greenfield apps.
Juraj is now available for hire

Portfolio

  • Trade Republic Bank GmbH
    Android Development, Jetpack Compose, Model View Intent (MVI), RxJava 2...
  • SAP
    Kotlin, Coroutines, Android Jetpack, Model View Viewmodel (MVVM), Dagger 2...
  • Holidu
    Java, Kotlin, Model View Viewmodel (MVVM), Firebase, Hilt...

Experience

  • Android 10 years
  • Java 10 years
  • Android Development 10 years
  • Kotlin 5 years
  • Coroutines 4 years
  • Jetpack Compose 2 years
  • Kotlin Multiplatform Mobile (KMM) 2 years
  • Model View Intent (MVI) 2 years

Location

Munich, Bavaria, Germany

Availability

Full-time

Preferred Environment

MacOS, IntelliJ, Android Studio, Git

The most amazing...

...project I’ve worked on is the official Corona-Warn-App for Germany, which helped slow down the spread of COVID-19 infections and most likely saved many lives.

Employment

  • Senior Android Developer

    2022 - 2022
    Trade Republic Bank GmbH
    • Implemented critical features for credit card processing.
    • Improved the overall UI and UX of a mobile app using the latest technologies, such as Android Jetpack.
    • Implemented multiple successful A/B tests. Increased app engagement and user retention.
    Technologies: Android Development, Jetpack Compose, Model View Intent (MVI), RxJava 2, Firebase, Material Design, Kotlin, Android Material Design, User Interface (UI), Model View Viewmodel (MVVM), GitHub, Dagger 2, Dependency Injection, A/B Testing, Android, CI/CD Pipelines, Continuous Integration (CI), Continuous Delivery (CD), SonarQube, Code Review, Source Code Review, Gradle, Git, Unit Testing, Mockito, Android Jetpack, Android Studio, User Experience (UX), Mobile App Development, Mobile, REST APIs
  • Senior Android Developer

    2021 - 2022
    SAP
    • Developed an app that helps trace infection chains of SARS-CoV-2 (which can cause COVID-19). Used the exposure notification API from Apple and Google.
    • Implemented and maintained critical features according to the requirements of the German government.
    • Created an automated screenshots pipeline using Firebase, which handled multiple languages and screen configurations.
    • Maintained an open-source project and took care of open issues and PR reviews.
    Technologies: Kotlin, Coroutines, Android Jetpack, Model View Viewmodel (MVVM), Dagger 2, Open Source, exposure notification api, Room, Retrofit 2, JSON Web Tokens (JWT), GitHub, RoomDB, Gradle, Material Design, Android Material Design, WorkManager API, Data Encryption, Continuous Delivery (CD), Continuous Integration (CI), CI/CD Pipelines, Git, Unit Testing, UI Testing, JUnit, Mockito, Espresso, Android Studio, IntelliJ IDEA, REST, APIs, User Experience (UX), Protobuf, Camera API, QR Codes, Bluetooth, Fastlane, Mobile App Development, Mobile, REST APIs
  • Android Developer

    2018 - 2020
    Holidu
    • Developed many challenging features like login, in-app bookings, and a theme-based search. Increased app engagement and overall app revenue.
    • Implemented image classification using machine learning running on mobile devices during the company hackathon.
    • Designed and implemented multiple REST APIs endpoints and microservices using the Spring Boot framework.
    • Migrated the legacy Java code base to Kotlin and increased testability, app stability, and test coverage.
    • Cleaned the app architecture and introduced dependency injection to the project.
    Technologies: Java, Kotlin, Model View Viewmodel (MVVM), Firebase, Hilt, Dependency Injection, Retrofit 2, REST, Elasticsearch, Grafana, Kibana, A/B Testing, Android, Android Development, Android Jetpack, Android Material Design, Android Studio, APIs, API Design, Back-end, Back-end Development, Amazon Web Services (AWS), Amazon S3 (AWS S3), Spring Boot, IntelliJ IDEA, JSON, Git, GitHub, Gradle, Machine Learning, Image Recognition, TensorFlow, User Experience (UX), Unit Testing, Integration Testing, Microservices, Scrum, Mobile App Development, Mobile, REST APIs, Android Animations
  • Lead Mobile Developer

    2015 - 2018
    Verusoft
    • Led a small team of programmers and designers. Built multiple successful mobile apps and games with more than 3,000,000 downloads and positive user reviews.
    • Worked closely with the Android Instant Apps as an early adopter. Worked with Google on implementing this feature.
    • Handled the entire software development life cycle, from the idea to the app design, implementation, launch, marketing, and maintenance.
    Technologies: Android Development, iOS, Unity SDK, Java, JavaScript, Google Play Store, App Store, App Store Optimization (ASO), Google AdSense, Google AdMob, In-app Purchases, Subscriptions, Flutter, Dart, Cross-platform, Cross-platform App Development, APK, Firebase, Crashlytics, Unit Testing, User Interface (UI), Android, Android SDK, Android API, Android Studio, Gradle, Game Design, Game Development, Team Leadership, Unity3D, DigitalOcean, A/B Testing, Mobile App Development, Mobile, REST APIs, Android Animations
  • Android Developer

    2014 - 2015
    Foundation
    • Worked on an Android client for one of the first B2B file synchronization platforms called Soonr Go, Acquired by Autotask Corporation.
    • Built the front end of an Android app using a synchronization library written in C++.
    • Accomplished big refactoring and a migrated legacy C++ core library to Java.
    Technologies: Java, Android NDK, Java Native Interface (JNI), C++, Subversion (SVN), Git, SQLite, C, Android SDK, Android Studio, Unit Testing, JUnit, Jenkins, Encryption, Data Encryption, Cross-platform, Cross-platform Libraries, Cross-platform App Development, File Sharing, CI/CD Pipelines, Continuous Integration (CI), Continuous Delivery (CD), B2B, Mobile App Development, Mobile, REST APIs
  • Software Developer

    2013 - 2014
    Siemens Convergence Creators (Atos)
    • Developed a multi-platform service for smart TV and web.
    • Implemented digital rights management to manage legal access to digital content.
    • Led the migration of a multi-media streaming service from the web to various smart TV devices.
    Technologies: JavaScript, CSS, HTML, AngularJS, Smart TV, Over-the-top Content (OTT), Media Player, Digital Rights Management (DRM), Roku, Widevine, REST APIs, Video on Demand (VOD)

Experience

  • Trade Republic: an Android Mobile Broker App
    https://traderepublic.com/

    Trade Republic Bank GmbH is a German online broker in Berlin. It allows shares, derivatives, and cryptocurrencies to be traded on its mobile app.

    I worked for Trade Republic as a freelance mobile developer together with a big team of internal developers. I implemented multiple successful experiments and improved the overall UI and UX of the mobile app using the latest technologies, such as Jetpack Compose.

  • Holidu: an Android Accommodation App
    https://www.holidu.com/

    Holidu is one of the fastest-growing travel tech companies worldwide. It's based in Munich, Germany, and provides a vacation rental meta-search engine. The app makes millions of travelers happy by helping them book the ideal accommodation for the lowest price.

    During more than two years in the company, I have converted the original Java codebase of the Holidu Android app to Kotlin. I increased test coverage, cleaned the app architecture, and introduced dependency injection to the project. I also developed many challenging features like Google Sign-in, theme-based search, and image classification using machine learning (hackathon project). In addition, I improved the look and feel of the app by implementing material design components, fancy transitions, and animations.

  • Corona-Warn-App: an Android Coronavirus App
    https://www.coronawarn.app/en/

    The Corona-Warn-App is an app that helps trace infection chains of SARS-CoV-2 (which can cause COVID-19) in Germany. The app is based on technologies with a decentralized approach and notifies users if they have been exposed to SARS-CoV-2. It is the main corona app for Germany, which is interconnected with the national health care system. Great emphasis is placed on data protection and transparency since the mobile app handles the sensitive health data of users. The project is open-source and available on GitHub.

    I worked on this project as a freelance developer and helped to implement many features, tests, and bug fixes. Even though the project was challenging in many ways, it was also a great experience as we helped many people and most likely saved some lives.

  • Nature and Relaxing Sounds
    https://github.com/jurajkusnier/relaxing-sounds

    The project follows media app architecture guidelines. It uses Android MediaPlayer to play audio files saved in the assets folder. Playback is available on Android phones, Android Auto, and the new Android Automotive OS (AAOS).

Skills

  • Languages

    Kotlin, Java, JavaScript, Dart, C++, C, CSS, HTML
  • Platforms

    Android, Mobile, Firebase, iOS, Amazon Web Services (AWS), DigitalOcean
  • Other

    Android Development, Mobile App Development, Jetpack Compose, User Interface (UI), Coroutines, Subscriptions, Kotlin Multiplatform Mobile (KMM), APIs, User Experience (UX), HTTP, Authentication, Integration, Android Architecture, Android Animations, Computer Networking, Informatics, Software Development, Material Design, A/B Testing, Open Source, exposure notification api, Room, Hilt, Google Play Store, App Store, Google AdMob, In-app Purchases, Java Native Interface (JNI), Smart TV, Over-the-top Content (OTT), Digital Rights Management (DRM), Exposure Notification System, Machine Learning, CI/CD Pipelines, Push Notifications, Code Review, Source Code Review, Data Encryption, UI Testing, Espresso, QR Codes, Bluetooth, API Design, Back-end, Back-end Development, Image Recognition, Integration Testing, Cross-platform App Development, APK, Game Design, Game Development, Team Leadership, Encryption, Cross-platform Libraries, File Sharing, Roku, Widevine, QA Testing, OAuth, SSL, SSL Certificates, Video on Demand (VOD), Audio
  • Frameworks

    Android SDK, Dagger 2, JSON Web Tokens (JWT), Flutter, AngularJS, Media Player, Mockito, JUnit, Spring Boot, Unity3D
  • Libraries/APIs

    RxJava 2, REST APIs, Retrofit 2, Google AdSense, WorkManager API, Protobuf, Camera API, TensorFlow, Android API, Material 2
  • Paradigms

    Model View Intent (MVI), Model View Viewmodel (MVVM), Design Patterns, Android Material Design, Dependency Injection, REST, App Store Optimization (ASO), Continuous Integration (CI), Continuous Delivery (CD), Unit Testing, Microservices, Cross-platform, B2B, Scrum
  • Tools

    Android Studio, Git, GitHub, Android Jetpack, Grafana, Kibana, Unity SDK, Android NDK, Subversion (SVN), Jenkins, SonarQube, Gradle, IntelliJ IDEA, Fastlane, Crashlytics, Android Auto
  • Storage

    Elasticsearch, SQLite, RoomDB, Amazon S3 (AWS S3), JSON

Education

  • Bachelor's Degree in Information Technology
    2008 - 2011
    Slovak University of Technology - Bratislava, Slovakia

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