At Spotify, we have historically built services based on our own proprietary messaging protocol and framework. Three years ago we kicked off the daunting multi-year task of migrating everything to gRPC. Migrating over 3000 services to gRPC poses interesting challenges, many of them are not technical in nature - it all boils down to questions of engineering culture and leadership at scale: How do you get 400 autonomous engineering teams to align on something as fundamental and cross-cutting as a new RPC framework? How do you roll-out gRPC at scale with minimal disruption to both the organization and to the end-user? This presentation will address these questions alongside more technical discussions of advanced gRPC concepts such as interceptors, load balancing, and traffic management and how they are essential in large distributed systems.