Contributed to Firefox DevTools and other parts of the Firefox codebase. Worked with various Mozilla teams, DevTools module peer. Landed over 200 patches and reviewed many others. Learning about the browser internals and the standards process. Participated at the Mozilla All Hands meeting in 2016. Implemented several complex high-value features that required understanding of both C++ and JavaScript parts of the codebase:
Inspecting Map/Set entries in object inspector (JS engine internals, debugger API, security considerations for trusted/untrusted code).
Showing XHR request stack traces in Netmonitor (networking stack, multiprocess architecture, service workers, JS engine internals).
WebSocket support for debugger server (WebSockets implementation, remote debugging protocol).
Refactoring Netmonitor frontend to React (React, Redux, Immutable.js, optimizing very performance-sensitive code).
Worked on video stream analysis server. Massively parallel download of video streams, applying fingerprinting and computer vision algorithms. Microservices architecture. Node.js, Python, Ansible, Docker.
Integrated the stream analysis into a custom video search engine based on Hadoop. Java, Python, GCE and AWS. Several open source contributions to Hadoop and FFmpeg (bugfixes in Java and C code)
Leading a team of developers that created Samepage, a collaboration server for small businesses. Creating a new product from scratch. Introducing new technologies into the company - Java, distributed version control, modern JavaScript frontend. Java-based server backend, rich Javascript UI (Ext JS and Sencha Touch). Participating in setting the product roadmap and strategy. Delivering regular updates with new features and improvements.
Started improving a trivial SMTP/POP3 server in Winroute Pro, then the company's flagship product. Expanded it into full email server package with IMAP, SMTP routing, antivirus/antispam filter, Webmail access and Qt-based administration console. Multiplatform C++: Windows, Linux, OS X.
In 2002, scaled the solution to run on a distributed cluster of servers, deployed at Atlas.cz, major Czech portal at the time, serving 100k+ active mailboxes.
Led the growing team while it was still small. Later handed over the project management responsibility, working as a product architect and senior developer.
In 2006-2007, worked on a storage backend for Kerio Outlook Connector, the first and only offline MAPI Message Store Provider developed outside Microsoft. Reverse engineering poorly documented APIs, optimizing an embedded Firebird SQL server.