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A tool to generate test reports from data input sources such as X-Unit xml reports, miniHIL proprietary formats (for execution and requirements traces) and pregenerated plant uml diagrams (svg). Java was chosen for the generator and data preprocessing since proprietary parts which had to be integrated were already implemented in Java. The Java CLI interface generates data for a self contained React based single page app which can be integrated into existing CI solutions or be viewed in the browser. After generation no backend is required.
The front end built for the PROTOS miniHIL, a small hardware-in-the-loop test rig. It is a React (Next.js) app that lets you watch a test run on the hardware as it happens: live logs, signal traces and execution state, all streamed from the device while the test executes. The harder problem behind the views was the data path and performance. A test run produces a lot of data on an MCU. Additionally, the goal was to allow the user to open multiple browser windows showing different aspects of the test run.
The data comes off the miniHIL hardware itself, an STM32-based MCU system that runs the test cases in real time. The hardware is connected to the PC via USB (1.1 full speed device). A Java backend on the PC owns that USB link, deserializes the low-level protocols, and exposes the result to the GUI over a WebSocket. Inside the browser a single shared worker holds the websocket connection and fans the decoded stream out to every open window.
Full-stack web application for digital workshop facilitation and business strategy development. Features real-time collaborative whiteboard with canvases for SWOT analysis, value proposition design, design thinking workshops, and business model development. Includes guided workshop templates, real-time cursor tracking, user presence indicators, and integrated tools for brainstorming, clustering, and presentation. Built with React frontend and NestJS backend with WebSocket support for realtime team collaboration.
I build this project as part of a 4 people startup team, in which I handled most of the tech work and coordinated one remote developer. The other team members focused on business development, marketing and customer acquisition. Unfortunately we could not acquire enough customers to make the project sustainable in the long run, so we had to discontinue it in 2022.
Collaborative jukebox for Spotify: guests search and vote, and the top‑voted track is auto‑queued a few seconds before the current one ends. QR codes planted around our flat during parties ended the music DJ duties for good. You don't like this track? Search and vote for the next one!
Android app to use an Android smartphone as an SMS gateway for other web applications. The app polled a backend service for outgoing SMS messages and sent them using the Android SMS API. Incoming SMS messages were forwarded to the backend service as needed. The app was build for an early stage startup with the goal to provide small rented solar systems in Africa (Ghana). After payment the user would receive a SMS with a code to unlock the solar system for a certain time period. The app was deployed in Ghana and was successfully used for a short period of time before the startup pivoted to a different field.
Web-based enterprise application for the meat producing industry (Schlachthof). Based on the same self-developed platform used for the courier logistics application, featuring integration of domain-specific import and export interfaces (e.g. EDIFACT) and generation of domain-specific PDF documents to fulfill regulatory requirements applicable to the meat processing industry in Germany. As of 2025, this application is still in active use.
Web-based enterprise application for courier logistics with carrier interfaces for 'derKurier', FedEx and GLS. Features automatic bookkeeping, invoicing, tax calculations, way bill generation and remote printing. Additional interfaces for payment imports using FinTS and exports to Datev, Stotax, Lexware. Built with self-developed backend framework including custom ORM and user rights management with full separation of frontend SPA and backend.