Juraj is available for hire

Juraj Kusnier

Verified Expert in Engineering

Android Developer

Location

Munich, Bavaria, Germany

Toptal 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, 他为大大小小的客户做过重要的项目, banks, 以及政府机构，并为数千万用户提供应用程序. Juraj knows how to deal with large legacy systems and quickly and effectively set up and launch greenfield apps.

Portfolio

Mawdoo3 Ltd

Flutter，跨平台，移动应用程序，实时聊天，Go, Android, iOS...

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...

Experience

Android Development - 10 years Android - 10 years Java - 10 years Kotlin - 6 years Coroutines - 4 years Kotlin移动多平台(KMM) - 2年模型视图意图(MVI) - 2年 Jetpack Compose - 2 years

Availability

Part-time

Preferred Environment

MacOS, IntelliJ IDEA, Android Studio, Git

The most amazing...

...我参与的项目是德国官方的冠状病毒预警应用程序, which helped slow down the spread of COVID-19 infections and most likely saved many lives.

Work Experience

全栈(Flutter/Go)开发人员

2023 - 2023

Mawdoo3 Ltd

带头创造了一个前沿, chat-based, 从头开始的跨平台移动应用, 作为一个健壮的MVP项目的基础.
Orchestrated the development of a comprehensive API framework and successfully integrated it with a dynamic back-end solution, ensuring the seamless connection of mobile clients with a custom AI model and the powerful GPT-4 API.
通过提供抛光，展示了卓越的效率, 在极其苛刻的时间框架内提供生产就绪的解决方案, 展示我在压力下茁壮成长的能力.

Technologies: Flutter，跨平台，移动应用程序，实时聊天，Go, Android, iOS, Google Cloud, Artificial Intelligence (AI), Machine Learning, Microservices, Docker, Minimum Viable Product (MVP), OpenAI GPT-4 API, Single Sign-on (SSO), Google Sign-in, Protobuf, gRPC, SDKs, Agile, PostgreSQL, Full-stack

Senior Android Developer

2022 - 2022

Trade Republic Bank GmbH

实现了简化信用卡处理的关键功能, 促进应用程序的财务效率.
Elevated the mobile app's overall user experience and interface using the latest technologies, such as Jetpack Compose, 以确保一个现代和用户友好的设计.
策略性地执行多个成功的A/B测试, 显著提高应用粘性和用户留存率.

技术:Android开发, 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, Test-driven Development (TDD), 行为驱动发展(BDD), Figma, Databases, RxJava, Networking, Mobile Development, Front-end, CircleCI, Testing, Mobile Applications, Mobile Apps, SDKs, Agile

Senior Android Developer

2021 - 2022

SAP

Developed an app that helps trace infection chains of SARS-CoV-2 (which can cause COVID-19). 使用苹果和谷歌的曝光通知API.
Implemented and maintained critical features according to the requirements of the German government.
使用Firebase创建了一个自动截图管道, 哪个处理多种语言和屏幕配置.
维护一个开源项目，处理公开问题和PR审查.

Technologies: Kotlin, Coroutines, Android Jetpack, Model View ViewModel (MVVM)， Dagger 2, Open Source, Notification Center, 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, Test-driven Development (TDD), 行为驱动发展(BDD), Figma, Databases, RxJava, Networking, Mobile Development, Front-end, CircleCI, Testing, Mobile Applications, Mobile Apps, SDKs, Agile, Barcode Reader

Android Developer

2018 - 2020

Holidu

Developed many challenging features like login, in-app bookings, and a theme-based search. 提高应用粘性和整体应用收益.
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.
将遗留Java代码库迁移到Kotlin并提高了可测试性, app stability, and test coverage.
清理了应用架构，并在项目中引入了依赖注入.

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, Test-driven Development (TDD), 行为驱动发展(BDD), Figma, Databases, RxJava, Networking, Mobile Development, Front-end, CircleCI, Testing, Mobile Applications, Mobile Apps, Maps, SDKs, Google Maps SDK, Google Maps API, Google Maps, Agile, PostgreSQL, ML Kit, Full-stack

Lead Mobile Developer

2015 - 2018

Verusoft

领导一个小的程序员和设计师团队. 开发了多款成功的手机应用和游戏,000,000次下载和积极的用户评价.
作为早期采用者，与Android Instant Apps密切合作. 与Google合作实现此功能.
处理整个软件开发生命周期, 从创意到应用设计, implementation, launch, marketing, and maintenance.

技术:Android开发, 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, Test-driven Development (TDD), 行为驱动发展(BDD), Databases, Audio Streaming, RxJava, Video Streaming, WebSockets, WebRTC, Networking, Mobile Development, Camera2 API, Minimum Viable Product (MVP), Front-end, Testing, Mobile Applications, Mobile Apps, SDKs, Agile, PostgreSQL, Full-stack, FlutterFlow, OpenGL, AI-generated Video

Android Developer

2014 - 2015

Foundation

Worked on an Android client for one of the first B2B file synchronization platforms called Soonr Go, 被Autotask Corporation收购.
Built the front end of an Android app using a synchronization library written in C++.
完成了大型重构，并将遗留c++核心库迁移到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, Test-driven Development (TDD), 行为驱动发展(BDD), Databases, JNI, Networking, Mobile Development, Front-end, Testing, Mobile Applications, Mobile Apps, SDKs

Software Developer

2013 - 2014

西门子融合创作者(Atos)

开发智能电视和网络的多平台服务.
实施数字版权管理，对数字内容的合法访问进行管理.
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 Players, 数字版权管理(DRM), Roku, Widevine, REST APIs, Video on Demand (VOD), Video Streaming, Networking, Web Development, Front-end, Testing, Mobile Apps, Android TV, IPTV, tvOS

Experience

贸易共和国:一个Android手机经纪人应用程序

http://traderepublic.com/

Trade Republic Bank GmbH是一家位于柏林的德国在线经纪商. 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: Android住宿应用

http://www.holidu.com/

Holidu是全球增长最快的旅游科技公司之一, which is based in Munich, Germany, 提供度假租赁元搜索引擎. The app makes millions of travelers happy by helping them book the ideal accommodation for the lowest price.

在公司工作了两年多, I have converted the original Java codebase of the Holidu Android app to Kotlin. I increased test coverage, cleaned the app architecture, 并在项目中引入了依赖注入. 我还开发了许多具有挑战性的功能，比如Google Sign-in, theme-based search, 以及使用机器学习进行图像分类(黑客马拉松项目). In addition, I improved the look and feel of the app by implementing material design components, fancy transitions, and animations.

Corona-Warn-App:一款安卓冠状病毒应用

http://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. 该项目是开源的，可以在GitHub上获得.

I worked on this project as a freelance developer and helped to implement many features, tests, and bug fixes. 尽管这个项目在很多方面都很有挑战性, it was also a great experience as we helped many people and most likely saved some lives.

Nature and Relaxing Sounds

http://github.com/jurajkusnier/relaxing-sounds

The project is an open-source Android app that implements the Media app architecture guidelines. It utilizes the Android MediaPlayer component to enable playback of audio files from the assets folder. 与Android手机兼容, Android Auto, 和安卓汽车操作系统(AAOS), 这款应用提供了多功能的音频播放体验. Its open-source nature invites community contributions and promotes transparency and innovation in its development.

Security Camera App with WebRTC

http://github.com/jurajkusnier/security-camera-demo

The project involves developing a security camera Android app that utilizes WebRTC, Jetpack Compose, and Kotlin. The app's primary purpose is to provide a security camera monitoring solution using local network connectivity without requiring an internet connection.

WebRTC Integration: The app leverages WebRTC technology to establish real-time communication and video streaming between two Android devices. 第一个作为服务器，播放来自摄像机的视频流. The second one works as a client and receives a video signal from the first device. This enables efficient and secure video and audio data transmission over the local network.

Signaling Server with Node.使用Node实现的信令服务器.Js在移动应用之间建立连接，促进通信. This server acts as a mediator, 处理信令消息并促进WebRTC会话的发起.

背景视频在Jetpack撰写-演示项目

http://github.com/jurajkusnier/jetpack-login-screen

The project is an open-source Android app that showcases the usage of background video in Jetpack Compose. The app leverages the ExoPlayer library to seamlessly display an endless video stream as a background element behind other UI components on the login screen.

The project's main focus is to demonstrate how Jetpack Compose can be used to create visually engaging user interfaces where a dynamic video plays in the background, 增强应用程序的整体美学.

通过集成ExoPlayer库, 该应用程序实现了流畅和不间断的视频播放, 为用户提供视觉上身临其境的体验. The endless video stream ensures that the background video remains captivating and engaging without interruptions or noticeable repetitions.

登录屏幕是演示此特性的主要用例, 因为它通常是用户交互的第一个点. 背景视频为登录屏幕增加了视觉上的吸引力, 创造更吸引人、更令人难忘的用户体验.

Education

2008 - 2011

信息技术学士学位

斯洛伐克科技大学-布拉迪斯拉发，斯洛伐克

Skills

Libraries/APIs

RxJava, RxJava 2, REST APIs, Google Maps SDK, Google Maps API, Google Maps, OpenGL, Retrofit 2, Google AdSense, WorkManager API, Protobuf, Camera API, TensorFlow, Android API, Material 2, WebRTC, Camera2 API

Tools

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

Frameworks

Flutter, Android SDK, JNI, Dagger 2, JSON Web Tokens (JWT), AngularJS, Media Players, Mockito, JUnit, Espresso, Spring Boot, Unity3D, gRPC

Paradigms

Dependency Injection, Mobile Development, Testing, Model View Intent (MVI), Model View ViewModel (MVVM), Cross-platform, Test-driven Development (TDD), 行为驱动发展(BDD), Agile, Design Patterns, Android Material Design, REST, App Store Optimization (ASO), Continuous Integration (CI), Continuous Delivery (CD), Unit Testing, Microservices, B2B, Scrum

Languages

Kotlin, Java, Dart, JavaScript, c++， C, CSS, HTML, Go

Platforms

iOS, Android, Mobile, Android TV, FlutterFlow, Firebase, Amazon Web Services (AWS), DigitalOcean, Docker, Android Automotive, tvOS

Storage

Databases, PostgreSQL, Elasticsearch, SQLite, RoomDB, Amazon S3 (AWS S3), JSON, Google Cloud

Industry Expertise

Telecommunications

Other

Android Development, Over-the-top Content (OTT), Mobile App Development, Networking, Front-end, Mobile Applications, Mobile Apps, Jetpack Compose, User Interface (UI), A/B Testing, Coroutines, Subscriptions, Kotlin移动多平台(KMM), APIs, User Experience (UX), HTTP, Authentication, Integration, Android Architecture, Android Animations, VoIP, Audio Streaming, Video Streaming, Minimum Viable Product (MVP), Maps, SDKs, Full-stack, Computer Networking, Informatics, Software Development, Material Design, Open Source, Room, Hilt, Google Play Store, App Store, Google AdMob, In-app Purchases, Java Native Interface (JNI), Smart TV, 数字版权管理(DRM), Exposure Notification System, Machine Learning, CI/CD Pipelines, Push Notifications, Code Review, Source Code Review, Data Encryption, UI Testing, 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, Notification Center, WebSockets, Web Development, Open-source Software (OSS), MVP Design, Videos, Video Players, Live Chat, Artificial Intelligence (AI), OpenAI GPT-4 API, Single Sign-on (SSO), Google Sign-in, Barcode Reader, ML Kit, IPTV, AI-generated Video

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