Microsoft uses Azure Cosmos DB in the Microsoft e-commerce platforms Windows Store and Xbox Live. Azure Cosmos DB can be used to store product data, search the products, and perform the session, which is very important for e-commerce applications.

Azure Cosmos DB can also be used for event sourcing using its own change feed functionality. Change feed provides the amazing event generation mechanism to handle micro service communication.

You can refer to the following diagram about micro service communication:

Change feed is a concept introduced by RethinkDB; Packt authored a book on this called Mastering RethinkDB.

Let's look at the next use case, which is my favorite one, gaming.