Microsoft Development Center Estonia, located in Tallinn and Tartu, is at the forefront of building the Intelligent Conversations & Communications Cloud (IC3). This platform powers communication services for millions of Microsoft customers worldwide across products like Skype, Teams, Xbox, Windows, and Azure. The IC3 Media Delivery Network Relay team is seeking a Senior Software Engineer to develop and operate a global fleet of TURN relays. This role involves working with critical infrastructure that directly impacts millions of users daily. The position requires expertise in C++ programming, networking, and distributed systems. You'll be part of a team ensuring high availability, resilience, and optimal performance while meeting strict quality, latency, compliance, and security requirements. Microsoft offers a collaborative environment with a growth mindset, comprehensive benefits, and the opportunity to work on large-scale applications ranging from real-time communications to commerce and anti-fraud systems. This role combines technical challenges with real-world impact, making it ideal for engineers passionate about building reliable, scalable communication infrastructure.