- Microsoft Azure Stack allows developers to build and test applications locally that are consistent with Azure. It provides a subset of Azure services and APIs on an on-premises software stack running on a physical server. - The Azure Stack Development Kit is a free tool that allows users to prototype applications locally in an environment that is consistent with the Azure public cloud. It has some limitations due to its small hardware footprint but provides a simple way to get started with Azure Stack development. - With Azure Stack, developers can build applications once and deploy them to any Azure cloud, including an on-premises Azure Stack environment. This provides a unified development and deployment experience across public and private clouds.