The most prominent shift we've observed in the field of distributed systems over the last decade is probably the transition from traditional synchronous integrated systems to message-driven means. This change is a logical response to the high demands for scalability, elasticity, and resilience within today's software systems. Regardless of how overwhelming the array of message-based options may seem, Azure Cosmos DB serves as an incredible solid backbone for most of them, whether utilized as a transactional outbox or a fully-fledged event store in the context of event-sourcing. By diving deeper into real-world experiences, we will discover the mechanics of how Cosmos DB can guarantee nearly infinite scalability if you follow a few basic principles and patterns to efficiently model your data. While Cosmos DB should not be considered as another silver bullet, this talk will teach you why you should certainly keep it as a prominent tool in your toolkit when it comes to building event-driven systems at scale.