The Azure Cosmos DB Linux emulator provides a local environment that emulates the Azure Cosmos DB service for development purposes on Linux and macOS. Currently, the Linux emulator only supports the Core (SQL) API. Using the emulator, you can develop and test your application locally, without creating an Azure subscription or incurring any costs. When you are satisfied with how your application is working in the Azure Cosmos DB emulator, you can switch to using an Azure Cosmos DB account in the cloud.
Learn more about Azure Cosmos DB Linux emulator.