Alessandro Pagnin focused on backend development and testing in Go, working on the uber/cosmo repository to enhance the security and reliability of its WebSocket subsystem. He addressed a critical issue where negotiation headers could leak into subgraph WebSocket connections, potentially exposing sensitive information. By strengthening header isolation and ensuring proper management during real-time communication, Alessandro reduced the risk of header exposure without impacting performance. His approach maintained clear traceability through detailed commit messages referencing related issues, supporting future audits. The work demonstrated a deep understanding of secure backend practices and contributed to more robust WebSocket flows within the codebase.