Azure Cosmos Emulator

Developers can run applications that use Azure Cosmos DB against a local environment that emulates the service. This gives them a practical place to build and test database-backed code while examining how the application behaves during local development. The emulator is designed for work that would otherwise begin by creating an Azure subscription, so an Azure Cosmos environment can be exercised before that cloud commitment.

It supports development and testing before an application is connected to an Azure Cosmos account in the cloud. Local testing also lets developers avoid Azure service costs while they refine the application and verify its behavior. After the application works as expected locally, the same development process can continue with an Azure Cosmos account in the cloud.

Azure Cosmos Emulator is a Windows system tool from Microsoft, distributed under a freeware license. Its role is to act as a local counterpart to Azure Cosmos DB rather than provide a separate cloud account, making it useful for developers writing or validating Azure Cosmos DB applications. The current version is 2.14.28.20260915.