Freelance Senior Full-stack Developer2017 - PRESENTWeatherWorks, LLC (via Toptal)
- Consulted on hardware and software infrastructure and technologies.
- Transformed a given design into a fully functional single page REST-backed web application.
- Implemented all parts of the front end using React and related libraries, including different roles, user, admin, and external developer dashboards.
- Wrote green papers on the infrastructure; opened the API for external developers, performance, and security improvements.
- Set up AWS Linux servers and deployed the back end, front end, and dependencies (including Nginx and firewalls).
- Engaged in problem analysis on the front end, back end, a MongoDB database, and the servers.
- Extended a Node.js back end, improved the codebase, and fixed memory leaks.
Frontend Developer for medical streaming and analysis app2020 - 2021Gepalon Networks Ltd (via Toptal)
Technologies: React, Node.js, MongoDB, PostgreSQL, Jitsi Meet
- Extended the Jitsi Meet platform to integrate artificial intelligence (neural network) generated image inference to highlight body tissue parts in a live video stream.
- Configured and integrated prosody modules of Jitsi Meet platform to allow token based video conference sessions, record join end end times.
- Created Node.js/Express based backend to store session and user information in PostgreSQL database.
- Created user and admin dashboards to handle user meta information in relation to Jitsi Meet sessions.
- Created Node.js backend to run TensorFlow inference as a REST service.
Senior Front-end Engineer2020 - 2020Brightpunch, Ltd. (via Toptal)
- Extended the Jitsi Meet video conferencing platform to allow participants to cooperatively draw with their mouse over the moderator's video stream after being granted permission.
- Added a custom toolbar containing shape, color, line width choosers, and undo, redo, and clear session control buttons.
- Leveraged an internal message passing facility using a custom message format.
Web Developer2017 - 2017Pixelrein
- Created a responsive web page for mobile devices on the basis of a desktop site.
Freelance Senior Java Developer | Freelance Consultant2016 - 2017TradeReplay (via Toptal)
Technologies: Back-end, Play, Git, Web Development, REST APIs, Full-stack, Nginx, Linux, PostgreSQL, Bootstrap, Java, Play Framework
- Consulted with clients on which technologies to use, cloud platforms, and payment providers.
- Created the hardware and software architecture, data model, and overview diagrams for the web-based self-service members' area of a standalone desktop app to provide functionalities for registration, profile change, subscription change as well as the administrative area.
- Developed the members' area based on Play Java with Twirl templates and Ebean ORM to PostgreSQL database.
- Installed a system and documented the setup on a Linux server—integrating WordPress for a third-party-provided public promotional website.
- Communicated with clients regularly, mainly through Asana, but also through email and phone—providing weekly progress reports.
Freelance Architect | Freelance Developer2016 - 2017Freelance Work
Technologies: Back-end, Git, Java, Play Framework, PostgreSQL, React
- Architected and single-handedly developed Trunksta.de, a social-sharing platform for sending items in other people's cars.
- Developed the front end as a single-page application with React/Redux.
- Implemented the back end with the Lightbend Play Java framework with an Nginx reverse proxy/load balancer and PostgreSQL database mapped to Java entities through Ebean-ORM.
- Specified infrastructure requirements and installed the system on Linux servers.
Service Consultant2015 - 2015Cellent AG (Fellbach, Germany)
Technologies: Back-end, Atlassian Confluence, Jira, Apache Struts, Jakarta EE, Java
- Provided second- and third-level support for a complex legacy web-based project-management system in the automotive industry spanning a variety of frameworks and technologies.
- Acted as the main customer contact for a major component.
- Coordinated incident support, maintained systems, performed analysis, and fixed bugs.
- Analyzed error reports and fixed bugs.
- Managed the database data and structures through manual SQL commands.
Software Development Engineer2013 - 2014Dell Inc./Dell SecureWorks (Edinburgh, UK)
Technologies: Back-end, Scrum, Full-stack, OpenGrok, iBATIS, MyBatis, Atlassian Confluence, Jira, FindBugs, Apache Tomcat, Ext JS, Maven, Perl, Bash, Linux, Java
- Extended and maintained complex, robust, and secure business-critical software systems for managed security services and counter-threat units.
- Fixed bugs in a legacy Perl application for manual and automatic device maintenance.
- Documented all parts of the newly built systems.
- Took part in daily scrum sessions.
- Performed user acceptance testing for newly developed features.
- Certified as a GIAC Secure Software Programmer-Java (GSSP-Java).
- Certified as a Cloudera Certified Developer for Apache Hadoop (CCDH).
Software Engineer2006 - 2013TomTom Software Ltd (Edinburgh, UK)
- Supported the maintenance and improvement of the in-house continuous integration system for automated tests.
- Created a tool to visualize a large number of trip logs into global and regional traffic heat maps.
- Supported a navigation device platform development through testing of WebKit, automatic route testing, and embedded testing/debugging.
- Created sample Android apps for current navigation devices to be included in an API toolkit for third parties extending the platform (e.g., Renault R-Link).
- Developed an SVN/Maven repository crawler to check for project health, inconsistencies, missing information, prevent bit rot, ensure buildability, detect dependency cycles, and identify logical build sequences.
- Created a RESTful web back end for a prototype device to store/retrieve data; implemented automatic tests.
- Ported a WebDAV server from C++ to Java.
Professional Systems Engineer2001 - 2005T-Systems GEI GmbH (Bonn, Germany)
Technologies: Back-end, AWT, Swing, PDF, XML, HTML, UML, CSV, Ant, JUnit, JDBC, SQL, Java
- Developed a GIS application to convert a detailed digital street map into an abstract motorway graph, processing highly-complex temporally-changing data structures with graph algorithms.
- Created a GUI program for GIS visualization of road maps.
- Built a back end of a web booking system for toll tickets including PDF creation.
- Supported new and junior team members to get acquainted with software.
- Introduced static metrics (metrics, code coverage, dependency analyses) into the build lifecycle.
- Wrote the end-user documentation for the GUI application.
Unix/Linux Systems Administrator1998 - 2001Tops.net GmbH & Co. KG (Bonn, Germany)
Technologies: LaTeX, Perl, Bash, Unix, Linux
- Supported and extended a Linux-based internet dial-up server for SoHo companies.
- Created the back end of a document management system converting SGML documents into PDF files via LaTeX.
- Managed client servers and networks.
- Set up and installed Linux-based servers.