The landscape of modern software engineering has shifted dramatically from monolithic, stateful applications toward decoupled, event-driven architectures. At the forefront of this evolution is the combination of Azure Functions and Azure Cosmos DB. This powerful duo enables developers to build systems that are massively scalable, cost-effective, and resilient.
In this article, we take a deep dive into the technical intricacies of building end-to-end event-driven systems. We explore the mechanics of the Cosmos DB Change Feed, architectural design patterns such as CQRS and Materialized Views, and practical implementation strategies for production-grade serverless applications.