Juraj Kusnier

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 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.

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.

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. With compatibility across Android phones, Android Auto, and Android Automotive OS (AAOS), the app offers a versatile audio playback experience. Its open-source nature invites community contributions and promotes transparency and innovation in its development.

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. The first one works as a server and broadcasts the video stream from the camera. 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.js: A signaling server implemented using Node.js establishes connections and facilitates communication between mobile apps. This server acts as a mediator, handling signaling messages and facilitating the initiation of WebRTC sessions.

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, enhancing the overall aesthetics of the app.

By integrating the ExoPlayer library, the app achieves smooth and uninterrupted video playback, providing a visually immersive experience to users. The endless video stream ensures that the background video remains captivating and engaging without interruptions or noticeable repetitions.

The login screen is a primary use case for demonstrating this feature, as it is often the first point of interaction for users. The background video adds a visually appealing touch to the login screen, creating a more captivating and memorable user experience.