• Scaled the technology and process department to support company growth from 60 to 200 people.• Contributed to the development of a major European transportation platform by providing 80–100 talented people belonging to 15 teams, led by 10 architects responsible for 80 microservices and the most critical business functionality.• Turned 20 people from individual contributors into team leaders, architects or chapter leads.• Raised average architect seniority in the company by creating an atmosphere of trust, cooperation and personal growth.• Migrated from proprietary C++ based instant messaging server to ejabberd, which handles 350 messages and 13,000 presence notifications per second.• Increased unit test coverage and taught developers to write valuable unit tests by conducting testing workshops in each development team, extended with a series of follow-ups and conference presentations.• Lowered the deployment and release time by migrating the whole company from SVN to Git and implementing Gitflow.• Improved communication between the company and its primary customer, which helped to reduce unexpected issues.

• Designed the architecture and led the implementation of the achievement module for a 15-million-user social media platform which was being called up to 2,500 times per second and used tens of gigabytes of data, yet its performance impact was negligible.• Allowed the design of new functionality for end users by improving the internal, Redis-like database’s performance.• Improved the integration with mobile applications thanks to the early and continuous release of documented REST API endpoints.

• Developed a social media platform based on geolocation that had 300,000 users and withstood traffic resulting from being featured in prime-time TV news watched by 4 million people.• Implemented Sphinx-based search engine (incl. geospatial search) that returned results in milliseconds and was regularly tested with hundreds of concurrent requests.• Extended the user search engine of an instant messaging platform used by 10 million users in a way that didn’t impact search performance.

• Reduced time required to implement repetitive tasks from by providing a framework for all the developers to use.• Prevented projects from a premature release by introducing a bug tracking system.• Developed web modules that required no further maintenance for years due to their resilient design and extensive testing.